@article{taussig_ghasemi_han_kwansa_li_keene_woodward_yingling_malliaras_gomez_et al._2024, title={Electrostatic self-assembly yields a structurally stabilized PEDOT:PSS with efficient mixed transport and high-performance OECTs}, volume={7}, ISSN={["2590-2385"]}, DOI={10.1016/j.matt.2023.12.021}, number={3}, journal={MATTER}, author={Taussig, Laine and Ghasemi, Masoud and Han, Sanggil and Kwansa, Albert L. and Li, Ruipeng and Keene, Scott T. and Woodward, Nathan and Yingling, Yaroslava G. and Malliaras, George G. and Gomez, Enrique D. and et al.}, year={2024}, month={Mar} }
 @article{marina_dyson_rodriguez-martinez_reid_li_rumbles_smilgies_amassian_campoy-quiles_stingelin_et al._2024, title={Using spatial confinement to decipher polymorphism in the organic semiconductor p-DTS(FBTTh<sub>2</sub>)<sub>2</sub>}, ISSN={["2050-7534"]}, url={https://doi.org/10.1039/D3TC03640E}, DOI={10.1039/D3TC03640E}, abstractNote={Spatial confinement at the nanoscale is exploited to achieve specific polymorphs in the organic semiconductor p-DTS(FBTTh2)2. A new polymorph exhibiting higher charge-carrier mobility compared to previously reported crystal form is found.}, journal={JOURNAL OF MATERIALS CHEMISTRY C}, author={Marina, Sara and Dyson, Matthew and Rodriguez-Martinez, Xabier and Reid, Obadiah G. and Li, Ruipeng and Rumbles, Garry and Smilgies, Detlef and Amassian, Aram and Campoy-Quiles, Mariano and Stingelin, Natalie and et al.}, year={2024}, month={Jan} }
 @article{guo_chauhan_woodward_mcandrews_thapa_lefler_li_wang_darabi_mcgehee_et al._2023, title={<i>In situ</i> Stress Monitoring Reveals Tension and Wrinkling Evolutions during Halide Perovskite Film Formation}, volume={9}, ISSN={["2380-8195"]}, DOI={10.1021/acsenergylett.3c02079}, abstractNote={Metal halide perovskites (MHPs) are promising candidates for next-generation thin film photovoltaics and high-performance tandems. Solution-processed MHP films are susceptible to residual stress that can induce undesirable surface wrinkles. However, the origins and evolution of stress during solution processing remain elusive. In this work, we utilize multimodal in situ characterizations, including substrate curvature, reflectance, absorbance, and photoluminescence, to monitor stress and morphology evolution during MHP film formation. A film formation model emerges, consisting of a perovskite top crust on a semirigid sol with the ability to transfer mechanical forces. The phase transformation induces tension in the MHP crust, while shrinkage of the sol causes additional compression and surface wrinkles. Wrinkle-free films are formed through dynamically balancing forces between the crust and the sol. This study provides a powerful toolkit for the fast-growing area of stress engineering in MHP photovoltaics to achieve dynamic control of film stress and surface morphology.}, number={1}, journal={ACS ENERGY LETTERS}, author={Guo, Boyu and Chauhan, Mihirsinh and Woodward, Nathaniel R. and McAndrews, Gabriel R. and Thapa, Gaurab J. and Lefler, Benjamin M. and Li, Ruipeng and Wang, Tonghui and Darabi, Kasra and McGehee, Michael D. and et al.}, year={2023}, month={Dec}, pages={75–84} }
 @article{ghasemi_guo_darabi_wang_wang_huang_lefler_taussig_chauhan_baucom_et al._2023, title={A multiscale ion diffusion framework sheds light on the diffusion-stability-hysteresis nexus in metal halide perovskites}, ISSN={["1476-4660"]}, DOI={10.1038/s41563-023-01488-2}, abstractNote={Stability and current-voltage hysteresis stand as major obstacles to the commercialization of metal halide perovskites. Both phenomena have been associated with ion migration, with anecdotal evidence that stable devices yield low hysteresis. However, the underlying mechanisms of the complex stability-hysteresis link remain elusive. Here we present a multiscale diffusion framework that describes vacancy-mediated halide diffusion in polycrystalline metal halide perovskites, differentiating fast grain boundary diffusivity from volume diffusivity that is two to four orders of magnitude slower. Our results reveal an inverse relationship between the activation energies of grain boundary and volume diffusions, such that stable metal halide perovskites exhibiting smaller volume diffusivities are associated with larger grain boundary diffusivities and reduced hysteresis. The elucidation of multiscale halide diffusion in metal halide perovskites reveals complex inner couplings between ion migration in the volume of grains versus grain boundaries, which in turn can predict the stability and hysteresis of metal halide perovskites, providing a clearer path to addressing the outstanding challenges of the field.}, journal={NATURE MATERIALS}, author={Ghasemi, Masoud and Guo, Boyu and Darabi, Kasra and Wang, Tonghui and Wang, Kai and Huang, Chiung-Wei and Lefler, Benjamin M. and Taussig, Laine and Chauhan, Mihirsinh and Baucom, Garrett and et al.}, year={2023}, month={Feb} }
 @article{park_wei_xu_atapattu_eickemeyer_darabi_grater_yang_liu_teale_et al._2023, title={Engineering ligand reactivity enables high-temperature operation of stable perovskite solar cells}, volume={381}, ISSN={["1095-9203"]}, DOI={10.1126/science.adi4107}, abstractNote={
            Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically. We found that fluorinated aniliniums offer interfacial passivation and simultaneously minimize reactivity with perovskites. Using this approach, we report a certified quasi–steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. In an encapsulated device operating at 85°C and 50% relative humidity, we document a 1560-hour
            T
            85
            at maximum power point under 1-sun illumination.
          }, number={6654}, journal={SCIENCE}, author={Park, So Min and Wei, Mingyang and Xu, Jian and Atapattu, Harindi R. and Eickemeyer, Felix T. and Darabi, Kasra and Grater, Luke and Yang, Yi and Liu, Cheng and Teale, Sam and et al.}, year={2023}, month={Jul}, pages={209–215} }
 @article{mcandrews_guo_morales_amassian_mcgehee_2023, title={How the dynamics of attachment to the substrate influence stress in metal halide perovskites}, url={https://doi.org/10.1063/5.0177697}, DOI={10.1063/5.0177697}, abstractNote={Metal halide perovskites have the potential to contribute to renewable energy needs as a high efficiency, low-cost alternative for photovoltaics. Initial power conversion efficiencies are superb, but improvements to the operational stability of perovskites are needed to enable extensive deployment. Mechanical stress is an important, but often misunderstood factor impacting chemical degradation and reliability during thermal cycling of perovskites. In this manuscript, we find that a commonly used equation based on the coefficient of thermal expansion (CTE) mismatch between perovskite and substrate fails to accurately predict residual stress following solution-based film formation. For example, despite similar CTEs there is a 60 MPa stress difference between narrow bandgap “SnPb perovskite” Cs0.25FA0.75Sn0.5Pb0.5I3 and “triple cation perovskite” Cs0.05MA0.16FA0.79Pb(I0.83Br0.17)3. A combination of in situ absorbance and substrate curvature measurements are used to demonstrate that partial attachment prior to the anneal can reduce residual stress and explain wide stress variations in perovskites.}, journal={APL Energy}, author={McAndrews, Gabriel R. and Guo, Boyu and Morales, Daniel A. and Amassian, Aram and McGehee, Michael D.}, year={2023}, month={Dec} }
 @article{comstock_chou_wang_wang_song_sklenar_amassian_zhang_lu_liu_et al._2023, title={Hybrid magnonics in hybrid perovskite antiferromagnets}, volume={14}, ISSN={["2041-1723"]}, url={https://doi.org/10.1038/s41467-023-37505-w}, DOI={10.1038/s41467-023-37505-w}, abstractNote={Abstract}, number={1}, journal={NATURE COMMUNICATIONS}, author={Comstock, Andrew H. and Chou, Chung-Tao and Wang, Zhiyu and Wang, Tonghui and Song, Ruyi and Sklenar, Joseph and Amassian, Aram and Zhang, Wei and Lu, Haipeng and Liu, Luqiao and et al.}, year={2023}, month={Apr} }
 @article{li_wang_amassian_forrest_2023, title={Instability of Non-fullerene Acceptors Used in Organic Solar Cells}, ISSN={["0160-8371"]}, DOI={10.1109/PVSC48320.2023.10359724}, abstractNote={Inspired by the recent progress of acceptor-donor-acceptor (A-D-A) type non-fullerene acceptors (NFAs) with easily tunable molecular structures and strong near-infrared (NIR) absorption, the Organic photovoltaic (OPV) cells achieved great progress in power conversion efficiencies (PCEs), especially ternary OPVs. The ternary OPVs with two different NFAs and a polymer donor have resulted in a record efficiency for a single-junction opaque OPV cell with PCE of 19.6% and a semitransparent cell with PCE of 11.4% and 47% visible transparency. Unfortunately, their ability to withstand use in adverse environments over long periods is, as yet largely unproven, and the causes of instability are not well understood. In addition, high reproducibility of ternary solar cells has yet to be achieved in the ternary NFA-based cells. In this work, we find that almost all the non-fullerene acceptors (NFAs) used in high efficiency ternary organic photovoltaic cells undergo reactions during blending that create a plethora of reaction products. Briefly, if two NFAs are blended in a solution at elevated temperature, the acceptor end groups exchange between the molecules, creating at times up to 6 different NFA molecules within the bulk heterojunction mixture. These reaction products are dipolar, leading to a decrease in charge extraction efficiency, changes in film morphology and in the photogeneration dynamics. This unanticipated result has significant impacts on ternary OPV performance, reliability and reproducibility.}, journal={2023 IEEE 50TH PHOTOVOLTAIC SPECIALISTS CONFERENCE, PVSC}, author={Li, Yongxi and Wang, Tonghui and Amassian, Aram and Forrest, Stephen}, year={2023} }
 @article{li_huang_mencke_kandappa_wang_ding_jiang_amassian_liao_thompson_et al._2023, title={Interactions between nonfullerene acceptors lead to unstable ternary organic photovoltaic cells}, volume={120}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.2301118120}, abstractNote={For organic photovoltaic (OPV) devices to achieve consistent performance and long operational lifetimes, organic semiconductors must be processed with precise control over their purity, composition, and structure. This is particularly important for high volume solar cell manufacturing where control of materials quality has a direct impact on yield and cost. Ternary-blend OPVs containing two acceptor–donor–acceptor (A–D–A)-type nonfullerene acceptors (NFAs) and a donor have proven to be an effective strategy to improve solar spectral coverage and reduce energy losses beyond that of binary-blend OPVs. Here, we show that the purity of such a ternary is compromised during blending to form a homogeneously mixed bulk heterojunction thin film. We find that the impurities originate from end-capping C=C/C=C exchange reactions of A–D–A-type NFAs, and that their presence influences both device reproducibility and long-term reliability. The end-capping exchange results in generation of up to four impurity constituents with strong dipolar character that interfere with the photoinduced charge transfer process, leading to reduced charge generation efficiency, morphological instabilities, and an increased vulnerability to photodegradation. As a consequence, the OPV efficiency falls to less than 65% of its initial value within 265 h when exposed to up to 10 suns intensity illumination. We propose potential molecular design strategies critical to enhancing the reproducibility as well as reliability of ternary OPVs by avoiding end-capping reactions.}, number={23}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Li, Yongxi and Huang, Xinjing and Mencke, Austin R. and Kandappa, Sunil Kumar and Wang, Tonghui and Ding, Kan and Jiang, Zuo-Quan and Amassian, Aram and Liao, Liang-Sheng and Thompson, Mark E. and et al.}, year={2023}, month={Jun} }
 @article{park_wei_lempesis_yu_hossain_agosta_carnevali_atapattu_serles_eickemeyer_et al._2023, title={Low-loss contacts on textured substrates for inverted perovskite solar cells}, ISSN={["1476-4687"]}, DOI={10.1038/s41586-023-06745-7}, journal={NATURE}, author={Park, So Min and Wei, Mingyang and Lempesis, Nikolaos and Yu, Wenjin and Hossain, Tareq and Agosta, Lorenzo and Carnevali, Virginia and Atapattu, Harindi R. and Serles, Peter and Eickemeyer, Felix T. and et al.}, year={2023}, month={Oct} }
 @article{wang_li_ardekani_serrano-lujan_wang_ramezani_wilmington_chauhan_epps_darabi_et al._2023, title={Sustainable materials acceleration platform reveals stable and efficient wide-bandgap metal halide perovskite alloys}, volume={6}, ISSN={["2590-2385"]}, DOI={10.1016/j.matt.2023.06.040}, abstractNote={The vast chemical space of emerging semiconductors, like metal halide perovskites, and their varied requirements for semiconductor applications have rendered trial-and-error environmentally unsustainable. In this work, we demonstrate RoboMapper, a materials acceleration platform (MAP), that achieves 10-fold research acceleration by formulating and palletizing semiconductors on a chip, thereby allowing high-throughput (HT) measurements to generate quantitative structure-property relationships (QSPRs) considerably more efficiently and sustainably. We leverage the RoboMapper to construct QSPR maps for the mixed ion FA1−yCsyPb(I1−xBrx)3 halide perovskite in terms of structure, bandgap, and photostability with respect to its composition. We identify wide-bandgap alloys suitable for perovskite-Si hybrid tandem solar cells exhibiting a pure cubic perovskite phase with favorable defect chemistry while achieving superior stability at the target bandgap of ∼1.7 eV. RoboMapper’s palletization strategy reduces environmental impacts of data generation in materials research by more than an order of magnitude, paving the way for sustainable data-driven materials research.}, number={9}, journal={MATTER}, author={Wang, Tonghui and Li, Ruipeng and Ardekani, Hossein and Serrano-Lujan, Lucia and Wang, Jiantao and Ramezani, Mahdi and Wilmington, Ryan and Chauhan, Mihirsinh and Epps, Robert W. and Darabi, Kasra and et al.}, year={2023}, month={Sep}, pages={2963–2986} }
 @article{corzo_wang_gedda_yengel_khan_li_niazi_huang_kim_baran_et al._2022, title={A Universal Cosolvent Evaporation Strategy Enables Direct Printing of Perovskite Single Crystals for Optoelectronic Device Applications}, volume={34}, ISSN={0935-9648 1521-4095}, url={http://dx.doi.org/10.1002/adma.202109862}, DOI={10.1002/adma.202109862}, abstractNote={Abstract}, number={9}, journal={Advanced Materials}, publisher={Wiley}, author={Corzo, Daniel and Wang, Tonghui and Gedda, Murali and Yengel, Emre and Khan, Jafar I and Li, Ruipeng and Niazi, Muhammad Rizwan and Huang, Zhengjie and Kim, Taesoo and Baran, Derya and et al.}, year={2022}, month={Jan}, pages={2109862} }
 @article{zhang_darabi_nia_krishna_ahlawat_guo_almalki_su_ren_bolnykh_et al._2022, title={A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics}, volume={13}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/s41467-021-27740-4}, DOI={10.1038/s41467-021-27740-4}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Zhang, Hong and Darabi, Kasra and Nia, Narges Yaghoobi and Krishna, Anurag and Ahlawat, Paramvir and Guo, Boyu and Almalki, Masaud Hassan S. and Su, Tzu-Sen and Ren, Dan and Bolnykh, Viacheslav and et al.}, year={2022}, month={Jan} }
 @article{dong_fu_seyitliyev_darabi_mendes_lei_chen_chang_amassian_gundogdu_et al._2022, title={Cavity Engineering of Perovskite Distributed Feedback Lasers}, volume={9}, ISSN={2330-4022 2330-4022}, url={http://dx.doi.org/10.1021/acsphotonics.2c00917}, DOI={10.1021/acsphotonics.2c00917}, number={9}, journal={ACS Photonics}, publisher={American Chemical Society (ACS)}, author={Dong, Qi and Fu, Xiangyu and Seyitliyev, Dovletgeldi and Darabi, Kasra and Mendes, Juliana and Lei, Lei and Chen, Yi-An and Chang, Chih-Hao and Amassian, Aram and Gundogdu, Kenan and et al.}, year={2022}, month={Aug}, pages={3124–3133} }
 @inproceedings{darabi_seyitliyev_guo_bateni_wang_ghasemi_taussig_abolhasani_gundogdu_amassian_2022, title={Colloidal nanostructures control the formation and orientation of quantum wells in layered hybrid perovskites (Conference Presentation)}, url={http://dx.doi.org/10.1117/12.2633675}, DOI={10.1117/12.2633675}, abstractNote={Controlling the formation, size distribution and orientation of quantum wells (QWs) in layered hybrid perovskite (LHP) thin films is foundational to their optoelectronic device applications. These applications require exquisite control of energy and charge transport which tend to be highly anisotropic in low-dimensional phases in LHP thin films. Here, we combine a powerful suite of multimodal in situ characterizations to elucidate the precise solution-to-solid conversion of the sol into the LHP thin film. We identify, for the first time, the presence of oriented colloidal transient nanostructures during spin coating well before the onset of crystallization of phases.}, booktitle={Organic and Hybrid Light Emitting Materials and Devices XXVI}, publisher={SPIE}, author={Darabi, Kasra and Seyitliyev, Dovletgeldi and Guo, Boyu and Bateni, Fazel and Wang, Tonghui and Ghasemi, Masoud and Taussig, Laine and Abolhasani, Milad and Gundogdu, Kenan and Amassian, Aram}, editor={Lee, Tae-Woo and So, Franky and Adachi, ChihayaEditors}, year={2022}, month={Oct} }
 @article{zhong_kirmani_lan_carpenter_rong-hui chew_awartani_yu_niazi_voznyy_hu_et al._2022, title={Conjugated polymers with controllable interfacial order and energetics enable tunable heterojunctions in organic and colloidal quantum dot photovoltaics}, volume={10}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/D1TA09544G}, DOI={10.1039/D1TA09544G}, abstractNote={Top and bottom surfaces of polymer films are used to construct interfaces in heterojunction based devices, affecting device figure of merit significantly with their different aggregation states.}, number={4}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={Zhong, Yufei and Kirmani, Ahmad R. and Lan, Xinzheng and Carpenter, Joshua and Rong-Hui Chew, Annabel and Awartani, Omar and Yu, Liyang and Niazi, Muhammad R. and Voznyy, Oleksandr and Hu, Hanlin and et al.}, year={2022}, pages={1788–1801} }
 @inproceedings{taussig_ghasemi_han_proksch_li_gomez_kwansa_yingling_malliaras_amassian_2022, title={Multi-scale ordering of PEDOT and PSS in the presence of ionic salts enables water-stable 2D/3D printable conductors and devices (Conference Presentation)}, url={http://dx.doi.org/10.1117/12.2633568}, DOI={10.1117/12.2633568}, abstractNote={Recent advancements in the field of organic electronics and bioelectronics have focused on the processing of PEDOT:PSS with ionic additives to promote high electrical conductivity and device performance. The combination of excellent electrical properties and tunable structure are increasingly attractive, however, the mechanism responsible for these properties, specifically from a solution-phase self-assembly perspective, is unknown. Herein, we reveal how solution-phase self-assembly of PEDOT:PSS with ionic additives leads to multiscale ordering which influences thin film microstructure, electronic properties, enables new additive manufacturing modalities, and applications in aqueous environments.}, booktitle={Organic and Hybrid Field-Effect Transistors XXI}, publisher={SPIE}, author={Taussig, Laine and Ghasemi, Masoud and Han, Sanggil and Proksch, Tatiana and Li, Ruipeng and Gomez, Enrique and Kwansa, Albert and Yingling, Yaroslava and Malliaras, George and Amassian, Aram}, editor={Jurchescu, Oana D. and McCulloch, IainEditors}, year={2022}, month={Oct} }
 @inproceedings{ghasemi_guo_huang_baucom_darabi_taussig_wang_kim_atkin_amassian_2022, title={Quantitative multiscale diffusion framework for metal halide perovskites}, url={http://dx.doi.org/10.1117/12.2633471}, DOI={10.1117/12.2633471}, abstractNote={Anomalous properties such as operational instability and photocurrent hysteresis in perovskite-based devices present a major obstacle to their future commercialization. Halide ion/defect migration has been widely accepted as one of the main mechanisms behind these limiting properties, but a definitive explanation of this relationship has remained elusive. Here, we present a quantitative multi-scale diffusion framework that fully describes halide diffusion in polycrystalline metal halide perovskites (MHPs). By using time-of-flight secondary ion mass spectroscopy (ToF-SIMS) technique we could simultaneously monitor both the fast grain boundary (GB) diffusivity and three to four orders of magnitude slower volume/bulk diffusivity. Our framework reveals an inverse relationship between the activation energies of GB (EGB) and volume (EV) diffusions, such that MHPs (such as MAPbI3) with a larger EV also possess a smaller EGB. Importantly, this relationship explains some of the most conflicting observations in the literature, namely that MHPs with improved stability typically exhibit reduced hysteresis, thanks to the simultaneous existence of small volume and large GB halide diffusivities, respectively, pointing us to propose a model of grain boundary “strength”. This nontrivial relation between volume and GB halide diffusivities is derived from a wide range of MHP systems, including MA- and FA-based iodide and bromide perovskites. Even when GB passivation approaches are used, GB diffusivity increases reducing hysteresis at the expense of volume diffusion, which enhances stability. The quantitative elucidation of multiscale halide diffusion in polycrystalline MHPs provides an important path toward addressing these outstanding issues.}, booktitle={Organic, Hybrid, and Perovskite Photovoltaics XXIII}, publisher={SPIE}, author={Ghasemi, Masoud and Guo, Boyu and Huang, Chiung-Wei and Baucom, Garrett and Darabi, Kasra and Taussig, Laine and Wang, Tonghui and Kim, Taesoo and Atkin, Joanna M. and Amassian, Aram}, editor={Li, Gang and Nguyen, Thuc-Quyen and Nogueira, Ana Flávia and Rand, Barry P. and Moons, Ellen and Stingelin, NatalieEditors}, year={2022}, month={Oct} }
 @article{dauzon_sallenave_plesse_goubard_amassian_anthopoulos_2022, title={Versatile methods for improving the mechanical properties of fullerene and non-fullerene bulk heterojunction layers to enable stretchable organic solar cells}, volume={10}, ISSN={2050-7526 2050-7534}, url={http://dx.doi.org/10.1039/D1TC05263B}, DOI={10.1039/D1TC05263B}, abstractNote={A cross-linker and an elastomer are used to increase the mechanical compliance of the active layer in organic solar cells based on fullerene and non-fullerene acceptors without compromising their performance.}, number={9}, journal={Journal of Materials Chemistry C}, publisher={Royal Society of Chemistry (RSC)}, author={Dauzon, Emilie and Sallenave, Xavier and Plesse, Cedric and Goubard, Fabrice and Amassian, Aram and Anthopoulos, Thomas D.}, year={2022}, pages={3375–3386} }
 @article{ghasemi_balar_peng_hu_qin_kim_rech_bidwell_mask_mcculloch_et al._2021, title={A molecular interaction-diffusion framework for predicting organic solar cell stability}, volume={20}, ISSN={["1476-4660"]}, DOI={10.1038/s41563-020-00872-6}, abstractNote={Rapid increase in the power conversion efficiency of organic solar cells (OSCs) has been achieved with the development of non-fullerene small-molecule acceptors (NF-SMAs). Although the morphological stability of these NF-SMA devices critically affects their intrinsic lifetime, their fundamental intermolecular interactions and how they govern property-function relations and morphological stability of OSCs remain elusive. Here, we discover that the diffusion of an NF-SMA into the donor polymer exhibits Arrhenius behaviour and that the activation energy E a  scales linearly with the enthalpic interaction parameters χ H  between the polymer and the NF-SMA. Consequently, the thermodynamically most unstable, hypo-miscible systems (high χ) are the most kinetically stabilized. We relate the differences in E a  to measured and selectively simulated molecular self-interaction properties of the constituent materials and develop quantitative property-function relations that link thermal and mechanical characteristics of the NF-SMA and polymer to predict relative diffusion properties and thus morphological stability.}, number={4}, journal={NATURE MATERIALS}, author={Ghasemi, Masoud and Balar, Nrup and Peng, Zhengxing and Hu, Huawei and Qin, Yunpeng and Kim, Taesoo and Rech, Jeromy J. and Bidwell, Matthew and Mask, Walker and McCulloch, Iain and et al.}, year={2021}, month={Apr}, pages={525-+} }
 @inproceedings{amassian_2021, title={Accelerating hybrid perovskite research through robotic micro-experimentation}, url={http://dx.doi.org/10.1117/12.2602797}, DOI={10.1117/12.2602797}, abstractNote={The vast chemical and processing universe of emerging halide perovskite materials can be overwhelming to traditional research practices. The sheer scale of the design problem and the emergent nature of many phenomena, including highly nonequilibrium thin film processing, complex solution-to-solid phase transformation can be overwhelming for traditional trial-and-error investigations. Solving such a complex problem would benefit from a robot-in-the-loop strategy that can accelerate many of the manual tasks as well as reduce cost and waste generation and support implementation of artificial intelligence. We present the RoboMapper, our recent effort to leverage robotic automation towards accelerating parameter space exploration and establishment of formulation-structure-property relationships with orders of magnitude enhancement in research efficiency. We will demonstrate formulation, printing and characterization of halide perovskites towards the aim of accelerating research workflows.}, booktitle={Organic and Hybrid Light Emitting Materials and Devices XXV}, publisher={SPIE}, author={Amassian, Aram}, editor={Lee, Tae-Woo and So, Franky and Adachi, ChihayaEditors}, year={2021}, month={Aug} }
 @article{ravishankar_charles_xiong_henry_swift_rech_calero_cho_booth_kim_et al._2021, title={Balancing crop production and energy harvesting in organic solar-powered greenhouses}, volume={2}, ISSN={["2666-3864"]}, DOI={10.1016/j.xcrp.2021.100381}, abstractNote={Adding semitransparent organic solar cells (ST-OSCs) to a greenhouse structure enables simultaneous plant cultivation and electricity generation, thereby reducing the greenhouse energy demand. However, there is a need to establish the impact of such systems on plant growth and indoor climate and to optimize system tradeoffs. In this work, we consider plant growth under OSCs and system-relevant design. We evaluate the growth of red leaf lettuce under ST-OSC filters and compare the impact of three different OSC active layers that have unique transmittance. We find no significant differences in the fresh weight and chlorophyll content of the lettuce grown under these OSC filters. In addition, OSCs provide an opportunity for further light and thermal management of the greenhouse through device design and optical coatings. The OSCs can thus affect plant growth, power generation, and thermal load of the greenhouse, and this design trade space is reviewed and exemplified.}, number={3}, journal={CELL REPORTS PHYSICAL SCIENCE}, publisher={Elsevier BV}, author={Ravishankar, Eshwar and Charles, Melodi and Xiong, Yuan and Henry, Reece and Swift, Jennifer and Rech, Jeromy and Calero, John and Cho, Sam and Booth, Ronald E. and Kim, Taesoo and et al.}, year={2021}, month={Mar} }
 @article{yu_pavlica_li_zhong_silva_bratina_müller_amassian_stingelin_2021, title={Conjugated Polymer Mesocrystals with Structural and Optoelectronic Coherence and Anisotropy in Three Dimensions}, volume={34}, ISSN={0935-9648 1521-4095}, url={http://dx.doi.org/10.1002/adma.202103002}, DOI={10.1002/adma.202103002}, abstractNote={Abstract}, number={1}, journal={Advanced Materials}, publisher={Wiley}, author={Yu, Liyang and Pavlica, Egon and Li, Ruipeng and Zhong, Yufei and Silva, Carlos and Bratina, Gvido and Müller, Christian and Amassian, Aram and Stingelin, Natalie}, year={2021}, month={Nov}, pages={2103002} }
 @article{giuri_munir_listorti_esposito corcione_gigli_rizzo_amassian_colella_2021, title={Implication of polymeric template agent on the formation process of hybrid halide perovskite films}, volume={32}, ISSN={0957-4484 1361-6528}, url={http://dx.doi.org/10.1088/1361-6528/abed72}, DOI={10.1088/1361-6528/abed72}, abstractNote={Abstract}, number={26}, journal={Nanotechnology}, publisher={IOP Publishing}, author={Giuri, Antonella and Munir, Rahim and Listorti, Andrea and Esposito Corcione, Carola and Gigli, Giuseppe and Rizzo, Aurora and Amassian, Aram and Colella, Silvia}, year={2021}, month={Apr}, pages={265707} }
 @article{huang_vardeny_wang_ahmad_chanana_vetter_yang_liu_galli_amassian_et al._2021, title={Observation of spatially resolved Rashba states on the surface of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> single crystals}, volume={8}, ISSN={1931-9401}, url={http://dx.doi.org/10.1063/5.0053884}, DOI={10.1063/5.0053884}, abstractNote={Hybrid organic-inorganic perovskites (HOIPs) are prime candidates for studying Rashba effects due to the heavy metal and halogen atoms in their crystal structure coupled with predicted inversion symmetry breaking. Nevertheless, observation of the Rashba effect in cubic CH3NH3PbBr3 single crystals that possess bulk inversion symmetry is the subject of extensive debate due to the lack of conclusive experiments and theoretical explanations. Here, we provide experimental evidence that Rashba state in cubic CH3NH3PbBr3 single crystals at room temperature occurs exclusively on the crystal surface and depends on specific surface termination that results in local symmetry breaking. We demonstrate this using a suite of spatially resolved and depth-sensitive techniques, including circular photogalvanic effect, inverse spin Hall effect, and multiphoton microscopy, that are supported by first principle calculations. Our work suggests using surface Rashba states in these materials for spintronic applications.}, number={3}, journal={Applied Physics Reviews}, publisher={AIP Publishing}, author={Huang, Zhengjie and Vardeny, Shai R. and Wang, Tonghui and Ahmad, Zeeshan and Chanana, Ashish and Vetter, Eric and Yang, Shijia and Liu, Xiaojie and Galli, Giulia and Amassian, Aram and et al.}, year={2021}, month={Sep}, pages={031408} }
 @article{chang_fan_zhao_fang_liu_tang_barrit_smilgies_li_lu_et al._2021, title={Perovskite Solar Cells toward Eco-Friendly Printing}, volume={2021}, ISSN={["2639-5274"]}, DOI={10.34133/2021/9671892}, abstractNote={
            Eco-friendly printing is important for mass manufacturing of thin-film photovoltaic (PV) devices to preserve human safety and the environment and to reduce energy consumption and capital expense. However, it is challenging for perovskite PVs due to the lack of eco-friendly solvents for ambient fast printing. In this study, we demonstrate for the first time an eco-friendly printing concept for high-performance perovskite solar cells. Both the perovskite and charge transport layers were fabricated from eco-friendly solvents
            via
            scalable fast blade coating under ambient conditions. The perovskite dynamic crystallization during blade coating investigated using
            in situ
            grazing incidence wide-angle X-ray scattering (GIWAXS) reveals a long sol-gel window prior to phase transformation and a strong interaction between the precursors and the eco-friendly solvents. The insights enable the achievement of high quality coatings for both the perovskite and charge transport layers by controlling film formation during scalable coating. The excellent optoelectronic properties of these coatings translate to a power conversion efficiency of 18.26% for eco-friendly printed solar cells, which is on par with the conventional devices fabricated
            via
            spin coating from toxic solvents under inert atmosphere. The eco-friendly printing paradigm presented in this work paves the way for future green and high-throughput fabrication on an industrial scale for perovskite PVs.
          }, journal={RESEARCH}, author={Chang, Xiaoming and Fan, Yuanyuan and Zhao, Kui and Fang, Junjie and Liu, Dongle and Tang, Ming-Chun and Barrit, Dounya and Smilgies, Detlef-M and Li, Ruipeng and Lu, Jing and et al.}, year={2021}, month={Feb} }
 @article{dauzon_sallenave_plesse_goubard_amassian_anthopoulos_2021, title={Pushing the Limits of Flexibility and Stretchability of Solar Cells: A Review}, volume={33}, ISSN={0935-9648 1521-4095}, url={http://dx.doi.org/10.1002/adma.202101469}, DOI={10.1002/adma.202101469}, abstractNote={Abstract}, number={36}, journal={Advanced Materials}, publisher={Wiley}, author={Dauzon, Emilie and Sallenave, Xavier and Plesse, Cedric and Goubard, Fabrice and Amassian, Aram and Anthopoulos, Thomas D.}, year={2021}, month={Jul}, pages={2101469} }
 @article{tang_dang_lee_barrit_munir_wang_li_smilgies_de wolf_kim_et al._2021, title={Wide and Tunable Bandgap MAPbBr
            <sub>
              3−
              <i>x
            
            Cl
            <sub>
              <i>x
            
            Hybrid Perovskites with Enhanced Phase Stability: In Situ Investigation and Photovoltaic Devices}, volume={5}, ISSN={2367-198X 2367-198X}, url={http://dx.doi.org/10.1002/solr.202000718}, DOI={10.1002/solr.202000718}, abstractNote={The current understanding of the crystallization, morphology evolution, and phase stability of wide‐bandgap hybrid perovskite thin films is very limited, as much of the community's focus is on lower bandgap systems. Herein, the crystallization behavior and film formation of a wide and tunable bandgap MAPbBr3−xClx system are investigated, and its formation and phase stability are contrasted to the classical MAPbI3−xBrx case. A multiprobe in situ characterization approach consisting of synchrotron‐based grazing incidence wide‐angle X‐ray scattering and laboratory‐based time‐resolved UV–Vis absorbance measurements is utilized to show that all wide‐bandgap perovskite compositions of MAPbBr3−xClx studied (0 < x < 3) crystallize the same way: the perovskite phase forms directly from the colloidal sol state and forms a solid film in the cubic structure. This results in significantly improved alloying and phase stability of these compounds compared with MAPbI3−xBrx systems. The phase transformation pathway is direct and excludes solvated phases, in contrast to methylammonium lead iodide (MAPbI3). The films benefit from antisolvent dripping to overcome the formation of discontinuous layers and enable device integration. Pin‐hole‐free MAPbBr3−xClx hybrid perovskite thin films with a tunable bandgap are, thus, integrated into working single‐junction solar cell devices and achieve a tunable open‐circuit voltage as high as 1.6 V.}, number={4}, journal={Solar RRL}, publisher={Wiley}, author={Tang, Ming-Chun and Dang, Hoang X. and Lee, Sehyun and Barrit, Dounya and Munir, Rahim and Wang, Kai and Li, Ruipeng and Smilgies, Detlef-M. and De Wolf, Stefaan and Kim, Dong-Yu and et al.}, year={2021}, month={Mar}, pages={2000718} }
 @article{tang_fan_barrit_chang_dang_li_wang_smilgies_liu_de wolf_et al._2020, title={Ambient blade coating of mixed cation, mixed halide perovskites without dripping: in situ investigation and highly efficient solar cells}, volume={8}, ISSN={["2050-7496"]}, DOI={10.1039/c9ta12890e}, abstractNote={Blade coating of mixed cation, mixed halide perovskite films is investigated using in situ X-ray scattering to investigate the role of formulations and processing routes and eliminate the need for anti-solvent dripping.}, number={3}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Tang, Ming-Chun and Fan, Yuanyuan and Barrit, Dounya and Chang, Xiaoming and Dang, Hoang X. and Li, Ruipeng and Wang, Kai and Smilgies, Detlef-M. and Liu, Shengzhong and De Wolf, Stefaan and et al.}, year={2020}, month={Jan}, pages={1095–1104} }
 @article{kirmani_eisner_mansour_firdaus_chaturvedi_seitkhan_nugraha_yarali_arquer_sargent_et al._2020, title={Colloidal Quantum Dot Photovoltaics Using Ultrathin, Solution-Processed Bilayer In2O3/ZnO Electron Transport Layers with Improved Stability}, volume={3}, ISBN={2574-0962}, DOI={10.1021/acsaem.0c00831}, abstractNote={Solution-processed colloidal quantum dot (CQD) photovoltaics (PVs) continue to mature with improvements in device architectures and ligand exchange strategies. Carrier selective contacts extract ph...}, number={6}, journal={ACS APPLIED ENERGY MATERIALS}, author={Kirmani, Ahmad R. and Eisner, Flurin and Mansour, Ahmed E. and Firdaus, Yuliar and Chaturvedi, Neha and Seitkhan, Akmaral and Nugraha, Mohamad I and Yarali, Emre and Arquer, F. Pelayo Garcia and Sargent, Edward H. and et al.}, year={2020}, pages={5135–5141} }
 @article{kirmani_luther_abolhasani_amassian_2020, title={Colloidal Quantum Dot Photovoltaics: Current Progress and Path to Gigawatt Scale Enabled by Smart Manufacturing}, volume={5}, url={https://doi.org/10.1021/acsenergylett.0c01453}, DOI={10.1021/acsenergylett.0c01453}, abstractNote={Colloidal quantum dots (QDs) have lately been pursued with intense vigor for optoelectronic applications such as photovoltaics (PV), flexible electronics, displays, mid-infrared photodetectors, las...}, number={9}, journal={ACS Energy Letters}, publisher={American Chemical Society (ACS)}, author={Kirmani, Ahmad R. and Luther, Joseph M. and Abolhasani, Milad and Amassian, Aram}, year={2020}, month={Sep}, pages={3069–3100} }
 @article{yi_peng_xu_seyitliyev_ho_danilov_kim_reynolds_amassian_gundogdu_et al._2020, title={Critical Role of Polymer Aggregation and Miscibility in Nonfullerene-Based Organic Photovoltaics}, volume={10}, ISSN={["1614-6840"]}, url={http://dx.doi.org/10.1002/aenm.201902430}, DOI={10.1002/aenm.201902430}, abstractNote={Abstract}, number={8}, journal={ADVANCED ENERGY MATERIALS}, author={Yi, Xueping and Peng, Zhengxing and Xu, Bing and Seyitliyev, Dovletgeldi and Ho, Carr Hoi Yi and Danilov, Evgeny O. and Kim, Taesoo and Reynolds, John R. and Amassian, Aram and Gundogdu, Kenan and et al.}, year={2020}, month={Feb} }
 @article{tang_fan_barrit_li_dang_zhang_magnanelli_nguyen_heilweil_hacker_et al._2020, title={Efficient Hybrid Mixed-Ion Perovskite Photovoltaics: In Situ Diagnostics of the Roles of Cesium and Potassium Alkali Cation Addition}, volume={4}, ISSN={["2367-198X"]}, DOI={10.1002/solr.202000272}, abstractNote={Perovskite photovoltaics have made extraordinary progress in power conversion efficiency (PCE) and stability due to process and formulation development. Perovskite cell performance benefits from the addition of alkali metal cations, such as cesium (Cs+) and potassium (K+) in mixed‐ion systems, but the underlying reasons are not fully understood. Herein, the solidification of perovskite layers is studied, incorporating 5%, 10%, to 20% of Cs+ and K+ using in situ grazing incidence wide‐angle X‐ray scattering. It is found that K+‐doped solutions yield nonperovskite 4H phase rather than the 3C perovskite phase. For Cs+‐doped formulations, both 4H and 3C phases are present at 5% Cs+, whereas the 3C perovskite phase is formed in 10% Cs+‐doped formulations, with undesirable halide segregation occurring at 20% Cs+. Postdeposition thermal annealing converts the intermediate 4H phase to the desirable 3C perovskite phase. Importantly, perovskite layers containing 5% of Cs+ or K+ exhibit a reduced concentration of trap states and enhanced carrier mobility and lifetime. By carefully adjusting Cs+ or K+ concentration to 5%, perovskite cells are demonstrated with a ≈5% higher‐average PCE than cells utilizing higher cation concentrations. Herein, unique insights into the crystallization pathways toward perovskite phase engineering and improved cell performance are provided.}, number={9}, journal={SOLAR RRL}, author={Tang, Ming-Chun and Fan, Yuanyuan and Barrit, Dounya and Li, Ruipeng and Dang, Hoang X. and Zhang, Siyuan and Magnanelli, Timothy J. and Nguyen, Nhan V. and Heilweil, Edwin J. and Hacker, Christina A. and et al.}, year={2020}, month={Sep} }
 @article{gao_quan_arquer_zhao_munir_proppe_quintero-bermudez_zou_yang_saidaminov_et al._2020, title={Efficient near-infrared light-emitting diodes based on quantum dots in layered perovskite (vol 13, pg 158, 2020)}, volume={14}, ISSN={["1749-4893"]}, DOI={10.1038/s41566-020-0635-8}, abstractNote={An amendment to this paper has been published and can be accessed via a link at the top of the paper.}, number={7}, journal={NATURE PHOTONICS}, author={Gao, Liang and Quan, Li Na and Arquer, F. Pelayo and Zhao, Yongbiao and Munir, Rahim and Proppe, Andrew and Quintero-Bermudez, Rafael and Zou, Chengqin and Yang, Zhenyu and Saidaminov, Makhsud I. and et al.}, year={2020}, month={Jul}, pages={459–459} }
 @article{islam_liu_boyd_zhong_nahid_henry_taussig_ko_nguyen_myers_et al._2020, title={Enhanced mid-wavelength infrared refractive index of organically modified chalcogenide (ORMOCHALC) polymer nanocomposites with thermomechanical stability}, volume={108}, ISSN={["1873-1252"]}, url={http://dx.doi.org/10.1016/j.optmat.2020.110197}, DOI={10.1016/j.optmat.2020.110197}, abstractNote={Abstract Organically modified chalcogenide (ORMOCHALC) polymers have proven to be alternatives to the conventional inorganic materials for mid-wavelength infrared (MWIR, λ = 3–5 μm) optical components. While the refractive index of ORMOCHALC can be reinforced by the content of chalcogenides such as sulfur (S) and selenium (Se), the increased portion of the S or Se deteriorate the thermomechanical stabilities. As a remedy, this study utilizes ZnS nanoparticles to reinforce both optical and thermomechanical properties of the sulfur-based ORMOCHALC polymer, poly(S-random-1,3-diisopropenylbenzene). The refractive index n and extinction coefficient k of the nanocomposites were characterized by Infrared Variable Angle Spectroscopic Ellipsometry (IR-VASE). The results show a significant increment in the refractive index of Δn = 6.58% at the wavelength of 4 μm by adding 20 wt% ZnS (or 7.29 vol%) in the ORMOCHALC polymer. The low extinction coefficient of the nanocomposites (}, journal={OPTICAL MATERIALS}, author={Islam, Md Didarul and Liu, Sipan and Boyd, Darryl A. and Zhong, Yaxu and Nahid, Masrur Morshed and Henry, Reece and Taussig, Laine and Ko, Yeongun and Nguyen, Vinh Q. and Myers, Jason D. and et al.}, year={2020}, month={Oct} }
 @article{kirmani_mansour_yang_munir_el-zohry_mohammed_amassian_2020, title={Facile and noninvasive passivation, doping and chemical tuning of macroscopic hybrid perovskite crystals}, volume={15}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0230540}, abstractNote={Halide vacancies and associated metallic lead (Pb°) observed at the surface and deep inside macroscopic organolead trihalide perovskite crystals is removed through a facile and noninvasive treatment. Indeed, Br2 vapor is shown to passivate Br-vacancies and associated Pb° in the bulk of macroscopic crystals. Controlling the exposure time can markedly improve the overall stoichiometry for moderate exposures or introduce excessive bromide for long exposures, resulting in p-doping of the crystals. In the low dose passivation regime, Hall effect measurements reveal a ca. 3-fold increase in carrier mobility to ca. 15 cm2V-1s-1, while the p-doping increases the electrical conductivity ca. 10000-fold, including a 50-fold increase in carrier mobility to ca. 150 cm2V-1s-1. The ease of diffusion of Br2 vapor into macroscopic crystals is ascribed to the porosity allowed in rapidly grown crystals through aggregative processes of the colloidal sol during growth of films and macroscopic crystals. This process is believed to form significant growth defects, including open voids, which may be remnants of the escaping solvent at the solidification front. These results suggest that due to the sol-gel-like nature of the growth process, macroscopic perovskite crystals reported in this study are far from perfect and point to possible pathways to improving the optoelectronic properties of these materials. Nevertheless, the ability of the vapor-phase approach to access and tune the bulk chemistry and properties of nominally macroscopic perovskite crystals provides interesting new opportunities to precisely manipulate and functionalize the bulk properties of hybrid perovskite crystals in a noninvasive manner.}, number={3}, journal={PLOS ONE}, author={Kirmani, Ahmad R. and Mansour, Ahmed E. and Yang, Chen and Munir, Rahim and El-Zohry, Ahmed M. and Mohammed, Omar F. and Amassian, Aram}, year={2020}, month={Mar} }
 @article{ho_kim_xiong_firdaus_yi_dong_rech_gadisa_booth_brendan t. o'connor_et al._2020, title={High-Performance Tandem Organic Solar Cells Using HSolar as the Interconnecting Layer}, volume={10}, ISSN={["1614-6840"]}, url={https://doi.org/10.1002/aenm.202000823}, DOI={10.1002/aenm.202000823}, abstractNote={Abstract}, number={25}, journal={ADVANCED ENERGY MATERIALS}, publisher={Wiley}, author={Ho, Carr Hoi Yi and Kim, Taesoo and Xiong, Yuan and Firdaus, Yuliar and Yi, Xueping and Dong, Qi and Rech, Jeromy J. and Gadisa, Abay and Booth, Ronald and Brendan T. O'Connor and et al.}, year={2020}, month={Jul} }
 @article{scaccabarozzi_basham_yu_westacott_zhang_amassian_mcculloch_caironi_gundlach_stingelin_2020, title={High-density polyethylene—an inert additive with stabilizing effects on organic field-effect transistors}, url={https://doi.org/10.1039/D0TC03173A}, DOI={10.1039/D0TC03173A}, abstractNote={The employment of binary blends comprising the insulating polymer HDPE in combination with hole- and electron-transporting organic semiconductors enables fabrication of OTFTs of notably improved device stability and performance.}, journal={Journal of Materials Chemistry C}, publisher={Royal Society of Chemistry (RSC)}, author={Scaccabarozzi, Alberto D. and Basham, James I. and Yu, Liyang and Westacott, Paul and Zhang, Weimin and Amassian, Aram and McCulloch, Iain and Caironi, Mario and Gundlach, David J. and Stingelin, Natalie}, year={2020} }
 @article{khan_sheikh_alamoudi_barrit_ugur_laquai_amassian_2020, title={Impact of Residual Lead Iodide on Photophysical Properties of Lead Triiodide Perovskite Solar Cells}, volume={8}, ISSN={["2194-4296"]}, DOI={10.1002/ente.201900627}, abstractNote={The role of residual lead iodide on the photophysical properties of methylammonium lead iodide is still unclear and contradictory views exist about its impact. Herein, it is reported that there is a critical amount of residual lead iodide, which is beneficial for the solar cell performance. Transient absorption spectroscopy is used to investigate the charge carrier recombination dynamics in perovskite solar cells and to address the role of different amounts of residual lead iodide. The amount of lead iodide is varied through the perovskite thin film preparation protocol upon a modified two‐step fabrication process. Slower carrier dynamics are observed at the perovskite/titanium dioxide interface in the presence of residual lead iodide when exciting the perovskite at the perovskite/titanium interface, which correlates with improved solar cell device performance. Excitation from the perovskite side indicates that the effect of residual lead iodide is primarily at the titanium dioxide interface. Increasing the lead iodide content does not further alter the carrier recombination; on the contrary, it results in lower device performance. This study confirms that the presence of lead iodide can have a beneficial effect, as it reduces charge carrier recombination at the perovskite/titanium dioxide interface.}, number={3}, journal={ENERGY TECHNOLOGY}, author={Khan, Jafar I and Sheikh, Arif D. and Alamoudi, Maha A. and Barrit, Dounya and Ugur, Esma and Laquai, Frederic and Amassian, Aram}, year={2020}, month={Mar} }
 @article{lee_tang_munir_barrit_kim_kang_yun_smilgies_amassian_kim_2020, title={In situ study of the film formation mechanism of organic-inorganic hybrid perovskite solar cells: controlling the solvate phase using an additive system}, volume={8}, ISSN={["2050-7496"]}, DOI={10.1039/d0ta00048e}, abstractNote={The role of the additive and solvate phases in the direct formation of perovskite crystals was revealed by in situ analysis during spin-coating condition.}, number={16}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Lee, Sehyun and Tang, Ming-Chung and Munir, Rahim and Barrit, Dounya and Kim, Yeon-Ju and Kang, Rira and Yun, Jin-Mun and Smilgies, Detlef-M. and Amassian, Aram and Kim, Dong-Yu}, year={2020}, month={Apr}, pages={7695–7703} }
 @article{kirmani_walters_kim_sargent_amassian_2020, title={Optimizing Solid-State Ligand Exchange for Colloidal Quantum Dot Optoelectronics: How Much Is Enough?}, volume={3}, url={https://doi.org/10.1021/acsaem.0c00389}, DOI={10.1021/acsaem.0c00389}, abstractNote={Progress in chalcogenide and perovskite CQD optoelectronics has relied to a significant extent on solid-state ligand exchanges (SSEs): the replacement of initial insulating ligands with shorter con...}, number={6}, journal={ACS Applied Energy Materials}, publisher={American Chemical Society (ACS)}, author={Kirmani, Ahmad R. and Walters, Grant and Kim, Taesoo and Sargent, Edward H. and Amassian, Aram}, year={2020}, month={Jun}, pages={5385–5392} }
 @article{barrit_cheng_darabi_tang_smilgies_liu_anthopoulos_zhao_amassian_2020, title={Room‐Temperature Partial Conversion of α‐FAPbI3 Perovskite Phase via PbI2 Solvation Enables High‐Performance Solar Cells}, url={https://doi.org/10.1002/adfm.201907442}, DOI={10.1002/adfm.201907442}, abstractNote={Abstract}, journal={Advanced Functional Materials}, author={Barrit, Dounya and Cheng, Peirui and Darabi, Kasra and Tang, Ming‐Chun and Smilgies, Detlef‐M. and Liu, Shengzhong and Anthopoulos, Thomas D. and Zhao, Kui and Amassian, Aram}, year={2020}, month={Mar} }
 @article{dauzon_lin_faber_yengel_sallenave_plesse_goubard_amassian_anthopoulos_2020, title={Stretchable and Transparent Conductive PEDOT:PSS-Based Electrodes for Organic Photovoltaics and Strain Sensors Applications}, volume={30}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.202001251}, abstractNote={Abstract}, number={28}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Dauzon, Emilie and Lin, Yuanbao and Faber, Hendrik and Yengel, Emre and Sallenave, Xavier and Plesse, Cedric and Goubard, Fabrice and Amassian, Aram and Anthopoulos, Thomas D.}, year={2020}, month={Jul} }
 @article{kim_lee_niazi_hwang_tang_lim_kang_smilgies_amassian_kim_2020, title={Systematic Study on the Morphological Development of Blade-Coated Conjugated Polymer Thin Films via In Situ Measurements}, volume={12}, url={https://doi.org/10.1021/acsami.0c07385}, DOI={10.1021/acsami.0c07385}, abstractNote={The morphology of conjugated polymer thin films, determined by the kinetics of film drying, is closely correlated with their electrical properties. Herein, we focused on dramatic changes in thin film morphology of blade-coated poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} caused by the effect of solvent and coating temperature. Through in situ measurements the evolution of polymer aggregates and crystallites, which plays a decisive role in the formation of the charge transporting pathway, was observed in real-time. By combining in situ ultraviolet-visible spectroscopy and in situ grazing-incidence wide-angle X-ray scattering analysis, we could identify five distinct stages during the blade-coating process; these stages were observed irrespective of the solvent and coating temperature used. The five stages are described in detail with a proposed model of film formation. This insight is an important step in understanding the relationship between the morphology of thin polymer films and their charge-transport properties as well as optimizing the structural evolution of thin films.}, number={32}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Kim, Yeon-Ju and Lee, Sehyun and Niazi, Muhammad. R. and Hwang, Kyoungtae and Tang, Ming-Chun and Lim, Dae-Hee and Kang, Ji-Sue and Smilgies, Detlef-M. and Amassian, Aram and Kim, Dong-Yu}, year={2020}, month={Aug}, pages={36417–36427} }
 @article{angunawela_nahid_ghasemi_amassian_ade_gadisa_2020, title={The Critical Role of Materials’ Interaction in Realizing Organic Field-Effect Transistors Via High-Dilution Blending with Insulating Polymers}, volume={12}, url={https://doi.org/10.1021/acsami.0c04208}, DOI={10.1021/acsami.0c04208}, abstractNote={High-performance low bandgap polymer semiconductors are visibly colored, making them unsuitable for transparent and imperceptible electronics without reducing film thickness to the nanoscale range. Herein, we demonstrate polymer/insulator blends exhibiting favorable miscibility that improves the transparency and carrier transport in an organic field-effect transistor (OFET) device. The mesoscale structures leading to more efficient charge transport in ultrathin films relevant to the realization of transparent and flexible electronic applications are explored based on thermodynamic material interaction principles, in conjunction with optical and morphological studies. By blending the commodity polymer polystyrene (PS) with two high-performing polymers, PDPP3T and P(NDI2OD-T2) (known as N2200), a drastic difference in morphology and fiber network are observed due to considerable differences in the degree of thermodynamic interaction between the conjugated polymers and PS. Intrinsic material interaction behavior establishes a long-range intermolecular interaction in the PDPP3T polymer fibrillar network dispersed in the majority (80%) PS matrix resulting in a ca. 3-fold increased transistor hole mobility of 1.15 cm2V-1s-1 (highest = 1.5 cm2V-1s-1) as compared to the pristine material, while PS barely affects the electron mobility in N2200. These basic findings provide important guidelines to achieve high mobility in transparent OFETs.}, number={23}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Angunawela, Indunil and Nahid, Masrur M. and Ghasemi, Masoud and Amassian, Aram and Ade, Harald and Gadisa, Abay}, year={2020}, month={Jun}, pages={26239–26249} }
 @article{tang_barrit_munir_li_barbé_smilgies_gobbo_anthopoulos_amassian_2019, title={Bismuth‐Based Perovskite‐Inspired Solar Cells: In Situ Diagnostics Reveal Similarities and Differences in the Film Formation of Bismuth‐ and Lead‐Based Films}, url={https://doi.org/10.1002/solr.201800305}, DOI={10.1002/solr.201800305}, abstractNote={Organic–inorganic lead‐based halide perovskite compounds currently yield thin film solar cells with a power conversion efficiency (PCE) of >23%. However, replacing the lead with less‐toxic elements while maintaining a high PCE remains a challenge. For this reason, there has been significant effort to develop Pb‐free compounds, including methylammonium bismuth iodide (MA3Bi2I9), but such systems severely underperform when compared with the prototypical Pb‐based methylammonium lead iodide (MAPbI3). For the latter, it is known that lead complexes with polar solvents, such as dimethyl sulfoxide (DMSO) and dimethylformamide (DMF), to form iodoplumbates which can co‐crystallize into solvated phases. Herein, the solidification and growth behaviors of Bi‐ and Pb‐based films is investigated using multi‐probe in situ characterization methods. It is shown that the Bi‐based compound crystallizes directly and rapidly into a textured polycrystalline microstructure from a precursor solution without evolving through intermediate crystalline solvated phases, in contrast to MAPbI3. This solidification process produces isolated crystals and challenges the growth of continuous and crystalline films required for solar cells. It is revealed that solvent engineering with antisolvent dripping is crucial to enable the formation of continuous polycrystalline films of MA3Bi2I9 and functional solar cells thereof.}, journal={Solar RRL}, author={Tang, Ming-Chun and Barrit, Dounya and Munir, Rahim and Li, Ruipeng and Barbé, Jérémy M. and Smilgies, Detlef-M. and Gobbo, Silvano Del and Anthopoulos, Thomas D. and Amassian, Aram}, year={2019}, month={Jul} }
 @article{dauzon_mansour_niazi_munir_smilgies_sallenave_plesse_goubard_amassian_2019, title={Conducting and Stretchable PEDOT:PSS Electrodes: Role of Additives on Self-Assembly, Morphology, and Transport}, volume={11}, url={https://doi.org/10.1021/acsami.9b00934}, DOI={10.1021/acsami.9b00934}, abstractNote={The addition of dimethylsulfoxide and Zonyl into poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) can be combined to achieve excellent electrical, optical, and mechanical properties. We demonstrate that it is possible to produce highly transparent conducting electrodes (FoM > 35) with low Young's modulus and high carrier density. We investigated the relationship between the transport properties of PEDOT:PSS and the morphology and microstructure of these films by performing Hall effect measurement, atomic force microscopy, and grazing incidence wide-angle X-ray scattering (GIWAXS). Our analysis reveals the distinctive impact of the two additives on the PEDOT and PSS components in the solid-state PEDOT:PSS films. Both additives induce fibrillar formation in the film, and the combination of the two additives only enhances the fibrillary nature and the aggregations of both PEDOT and PSS components of the film. In situ GIWAXS allows to time-resolve the morphology evolution. Our analysis reveals the influence of additives on the aggregation and self-assembly behaviors of the PEDOT and PSS components. Aggregation occurs during the transition from wet to dry film, which is observed exclusively during the thermal annealing step of the as-cast hydrated film. These results indicate that the additives directly influence the self-assembly behaviors of PEDOT and PSS during the ink-to-solid phase transformation of the hydrated film, which occurs primarily during the initial seconds of post-deposition thermal annealing.}, number={19}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Dauzon, Emilie and Mansour, Ahmed E. and Niazi, Muhammad R. and Munir, Rahim and Smilgies, Detlef-M. and Sallenave, Xavier and Plesse, Cedric and Goubard, Fabrice and Amassian, Aram}, year={2019}, month={May}, pages={17570–17582} }
 @article{serrano-luján_víctor-román_toledo_sanahuja-parejo_mansour_abad_amassian_benito_maser_urbina_2019, title={Environmental impact of the production of graphene oxide and reduced graphene oxide}, volume={1}, url={https://doi.org/10.1007/s42452-019-0193-1}, DOI={10.1007/s42452-019-0193-1}, abstractNote={Reduced graphene oxide (rGO) is widely seen as the most promising route for the low-cost mass production of graphene for many applications ranging from ultrathin electrodes to structural nanocomposites. The Hummers and Marcano methods are the two most successful approaches for producing high-performance rGO, but have been criticized for producing toxic emissions. We have applied life cycle assessment methodology to evaluate the environmental impacts of both production routes for GO and rGO in the context of applications requiring bulk materials or thin coatings. We find no current obstacle to the industrial scale production of graphene arising from its environmental impact. The cumulative energy demand is found to have a cap value between 20.7 and 68.5 GJ/Kg, a relatively high value; impact in other categories (such as human toxicity or resource depletion) is lower, and materials inventory does not include critical/strategic materials other than graphite itself. Our study proposes 1 kg of graphene as functional unit, and an application-specific functional unit normalized by conductivity which show that Hummers production method is far more suitable for bulk applications of graphene, with lower embedded energy per kg of graphene production, while Marcano’s production method is better suited for thin film electronic applications.}, number={2}, journal={SN Applied Sciences}, publisher={Springer Science and Business Media LLC}, author={Serrano-Luján, L. and Víctor-Román, S. and Toledo, C. and Sanahuja-Parejo, O. and Mansour, A. E. and Abad, J. and Amassian, A. and Benito, A. M. and Maser, W. K. and Urbina, A.}, year={2019}, month={Feb} }
 @article{barrit_cheng_tang_wang_dang_smilgies_liu_anthopoulos_zhao_amassian_2019, title={Impact of the Solvation State of Lead Iodide on Its Two‐Step Conversion to MAPbI3: An In Situ Investigation}, url={https://doi.org/10.1002/adfm.201807544}, DOI={10.1002/adfm.201807544}, abstractNote={Abstract}, journal={Advanced Functional Materials}, author={Barrit, Dounya and Cheng, Peirui and Tang, Ming‐Chun and Wang, Kai and Dang, Hoang and Smilgies, Detlef‐M. and Liu, Shengzhong and Anthopoulos, Thomas D. and Zhao, Kui and Amassian, Aram}, year={2019}, month={Nov} }
 @article{niu_lu_jia_xu_tang_barrit_yuan_ding_zhang_fan_et al._2019, title={Interfacial Engineering at the 2D/3D Heterojunction for High-Performance Perovskite Solar Cells}, volume={19}, ISSN={["1530-6992"]}, DOI={10.1021/acs.nanolett.9b02781}, abstractNote={Perovskite solar cells based on two-dimensional/three-dimensional (2D/3D) hierarchical structure have attracted significant attention in recent years due to their promising photovoltaic performance and stability. But to obtain a detailed understanding of interfacial mechanism at the 2D/3D heterojunction, e.g. the ligand-chemistry dependent nature of the 2D/3D heterojunction and its influence on charge collection and the final photovoltaic outcome, is not yet fully developed. Here we demonstrate that the underlying 3D phase templates growth of quantum wells (QWs) within 2D capping layer, which is further influenced by the fluorination of spacers and compositional engineering in terms of thickness distribution and orientation. Better QW alignment and faster dynamics of charge transfer at the 2D/3D heterojunction result in higher charge mobility and lower charge recombination loss, largely explaining the significant improvements in charge collection and open-circuit voltage (VOC) in complete solar cells. As a result, 2D/3D solar cells with power-conversion efficiency (PCE) of 21.15% were achieved, significantly higher than the 3D counterpart (19.02%). This work provides key missing information on how interfacial engineering influences the desirable electronic properties of the 2D/3D hierarchical films and device performance via ligand chemistry and compositional engineering in QW layer.}, number={10}, journal={NANO LETTERS}, author={Niu, Tianqi and Lu, Jing and Jia, Xuguang and Xu, Zhuo and Tang, Ming-Chun and Barrit, Dounya and Yuan, Ningyi and Ding, Jianning and Zhang, Xu and Fan, Yuanyuan and et al.}, year={2019}, month={Oct}, pages={7181–7190} }
 @article{wang_tang_dang_munir_barrit_bastiani_aydin_smilgies_wolf_amassian_2019, title={Kinetic Stabilization of the Sol–Gel State in Perovskites Enables Facile Processing of High‐Efficiency Solar Cells}, url={https://doi.org/10.1002/adma.201808357}, DOI={10.1002/adma.201808357}, abstractNote={Abstract}, journal={Advanced Materials}, author={Wang, Kai and Tang, Ming‐Chun and Dang, Hoang X. and Munir, Rahim and Barrit, Dounya and Bastiani, Michele De and Aydin, Erkan and Smilgies, Detlef‐M. and Wolf, Stefaan De and Amassian, Aram}, year={2019}, month={Aug} }
 @article{liu_chen_tan_quintero-bermudez_proppe_munir_tan_voznyy_scheffel_walters_et al._2019, title={Lattice anchoring stabilizes solution-processed semiconductors}, volume={570}, ISSN={["1476-4687"]}, DOI={10.1038/s41586-019-1239-7}, abstractNote={The stability of solution-processed semiconductors remains an important area for improvement on their path to wider deployment. Inorganic caesium lead halide perovskites have a bandgap well suited to tandem solar cells 1  but suffer from an undesired phase transition near room temperature 2 . Colloidal quantum dots (CQDs) are structurally robust materials prized for their size-tunable bandgap 3 ; however, they also require further advances in stability because they are prone to aggregation and surface oxidization at high temperatures as a consequence of incomplete surface passivation 4,5 . Here we report 'lattice-anchored' hybrid materials that combine caesium lead halide perovskites with lead chalcogenide CQDs, in which lattice matching between the two materials contributes to a stability exceeding that of the constituents. We find that CQDs keep the perovskite in its desired cubic phase, suppressing the transition to the undesired lattice-mismatched phases. The stability of the CQD-anchored perovskite in air is enhanced by an order of magnitude compared with pristine perovskite, and the material remains stable for more than six months at ambient conditions (25 degrees Celsius and about 30 per cent humidity) and more than five hours at 200 degrees Celsius. The perovskite prevents oxidation of the CQD surfaces and reduces the agglomeration of the nanoparticles at 100 degrees Celsius by a factor of five compared with CQD controls. The matrix-protected CQDs show a photoluminescence quantum efficiency of 30 per cent for a CQD solid emitting at infrared wavelengths. The lattice-anchored CQD:perovskite solid exhibits a doubling in charge carrier mobility as a result of a reduced energy barrier for carrier hopping compared with the pure CQD solid. These benefits have potential uses in solution-processed optoelectronic devices.}, number={7759}, journal={NATURE}, author={Liu, Mengxia and Chen, Yuelang and Tan, Chih-Shan and Quintero-Bermudez, Rafael and Proppe, Andrew H. and Munir, Rahim and Tan, Hairen and Voznyy, Oleksandr and Scheffel, Benjamin and Walters, Grant and et al.}, year={2019}, month={Jun}, pages={96-+} }
 @article{dang_wang_ghasemi_tang_de bastiani_aydin_dauzon_barrit_peng_smilgies_et al._2019, title={Multi-cation Synergy Suppresses Phase Segregation in Mixed-Halide Perovskites}, volume={3}, ISSN={["2542-4351"]}, DOI={10.1016/j.joule.2019.05.016}, abstractNote={Mixed lead halide perovskite solar cells have been demonstrated to benefit tremendously from the addition of Cs+ and Rb+, but its root cause is yet to be understood. This hinders further improvement, and processing approaches remain largely empirical. We address the challenge by tracking the solidification of precursors in situ and linking the evolutions of different crystalline phases to the presence of Cs+ and Rb+. In their absence, the perovskite film is inherently unstable, segregating into MA-I- and FA-Br-rich phases. Adding either Cs+ or Rb+ is shown to alter the solidification process of the perovskite films. The optimal addition of both Cs+ and Rb+ drastically suppress phase segregation and promotes the spontaneous formation of the desired α phase. We propose that the synergistic effect is due to the collective benefits of Cs+ and Rb+ on the formation kinetics of the α phase and on the halide distribution throughout the film.}, number={7}, journal={JOULE}, author={Dang, Hoang X. and Wang, Kai and Ghasemi, Masoud and Tang, Ming-Chun and De Bastiani, Michele and Aydin, Erkan and Dauzon, Emilie and Barrit, Dounya and Peng, Jun and Smilgies, Detlef-M and et al.}, year={2019}, month={Jul}, pages={1746–1764} }
 @article{fan_fang_chang_tang_barrit_xu_jiang_wen_zhao_niu_et al._2019, title={Scalable Ambient Fabrication of High-Performance CsPbI2Br Solar Cells}, volume={3}, ISSN={["2542-4351"]}, DOI={10.1016/j.joule.2019.07.015}, abstractNote={All-inorganic halide perovskites hold promise for emerging thin-film photovoltaics due to their excellent thermal stability. Unfortunately, it has been challenging to achieve high-quality films over large areas using scalable methods under realistic ambient conditions. Herein, we investigated the coupling between the fluid dynamics and the structural evolution during controlled film formation for ambient scalable fabrication of CsPbI2Br perovskite films using blade coating. We simultaneously overcame the negative influences of moisture attack and the Bénard-Marangoni instability in the drying ink and achieved an ideal sequential crystallization with changing halide composition during the film formation. As a result, we produced highly crystalline, uniform, and pinhole-free CsPbI2Br films with superior photophysical and transport properties. High-performance solar cells are fabricated to achieve power conversion efficiencies (PCEs) of 14.7% for small-aperture-area (0.03 cm2) devices and 12.5% for the large-aperture-area (1.0 cm2) ones, the highest PCE reported to date for large-area all-inorganic perovskite solar cells.}, number={10}, journal={JOULE}, author={Fan, Yuanyuan and Fang, Junjie and Chang, Xiaoming and Tang, Ming-Chun and Barrit, Dounya and Xu, Zhuo and Jiang, Zhiwu and Wen, Jialun and Zhao, Huan and Niu, Tianqi and et al.}, year={2019}, month={Oct}, pages={2485–2502} }
 @article{zhong_munir_li_tang_niazi_smilgies_zhao_amassian_2018, title={Blade-Coated Hybrid Perovskite Solar Cells with Efficiency > 17%: An In Situ Investigation}, volume={3}, url={https://doi.org/10.1021/acsenergylett.8b00428}, DOI={10.1021/acsenergylett.8b00428}, abstractNote={Blade-coating has recently emerged as a scalable fabrication method for hybrid perovskite solar cells, but it currently underperforms spin-coating, yielding a power conversion efficiency (PCE) of ∼15% for CH3NH3PbI3 (MAPbI3). We investigate the solidification of MAPbI3 films in situ during spin/blade-coating using optical and X-ray scattering methods. We find that the coating method and conditions profoundly influence the crystallization process, which proceeds through intermediate crystalline solvates. The polymorphism and composition of the solvates are mediated by the solvent removal rate dictated by the process temperature in blade-coating. Low to intermediate temperatures (25–80 °C) yield solvates with differing compositions and yield poor PCEs (∼5–8%) and a large spread (±2.5%). The intermediate solvates are not observed at elevated temperatures (>100 °C), pointing to direct crystallization of the perovskite from the sol–gel ink. These conditions yield large and compact spherulitic domains of perovs...}, number={5}, journal={ACS Energy Letters}, publisher={American Chemical Society (ACS)}, author={Zhong, Yufei and Munir, Rahim and Li, Jianbo and Tang, Ming-Chun and Niazi, Muhammad R. and Smilgies, Detlef-M. and Zhao, Kui and Amassian, Aram}, year={2018}, month={May}, pages={1078–1085} }
 @article{yu_li_yu_niazi_zou_corzo_basu_ma_dey_tietze_et al._2018, title={Single crystal hybrid perovskite field-effect transistors}, volume={9}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-018-07706-9}, abstractNote={Abstract}, journal={NATURE COMMUNICATIONS}, author={Yu, Weili and Li, Feng and Yu, Liyang and Niazi, Muhammad R. and Zou, Yuting and Corzo, Daniel and Basu, Aniruddha and Ma, Chun and Dey, Sukumar and Tietze, Max L. and et al.}, year={2018}, month={Dec} }
 @article{walters_wei_voznyy_quintero-bermudez_kiani_smilgies_munir_amassian_hoogland_sargent_2018, title={The quantum-confined Stark effect in layered hybrid perovskites mediated by orientational polarizability of confined dipoles}, volume={9}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-018-06746-5}, abstractNote={Abstract}, journal={NATURE COMMUNICATIONS}, author={Walters, G. and Wei, M. and Voznyy, O. and Quintero-Bermudez, R. and Kiani, A. and Smilgies, D. -M. and Munir, R. and Amassian, A. and Hoogland, S. and Sargent, E.}, year={2018}, month={Oct} }
 @article{sheikh_munir_haque_bera_hu_shaikh_amassian_wu_2017, title={Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction}, volume={9}, url={https://doi.org/10.1021/acsami.7b11250}, DOI={10.1021/acsami.7b11250}, abstractNote={In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic (PV) performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After temperature-dependent grazing-incidence wide-angle X-ray scattering, in situ X-ray diffraction, and optical absorption experiments were carried out, the thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10% in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of the crystallinity and p doping in the hole transporter, spiro-OMeTAD, which promotes the efficient extraction of photogenerated carriers. However, further thermal cycles produced a detrimental effect on the PV performance of PSCs, with the short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the PV performance of PSCs degraded at high operation temperatures; both the short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of the fill factor was the opposite. Our impedance spectroscopy analysis revealed a monotonous increase of the charge-transfer resistance and a concurrent decrease of the charge-recombination resistance with increasing temperature, indicating a high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance because of the deteriorated interfacial photocarrier extraction. The present findings suggest that the development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite PVs in harsh thermal environments.}, number={40}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Sheikh, Arif D. and Munir, Rahim and Haque, Md Azimul and Bera, Ashok and Hu, Weijin and Shaikh, Parvez and Amassian, Aram and Wu, Tom}, year={2017}, month={Oct}, pages={35018–35029} }
 @article{hynynen_kiefer_yu_kroon_munir_amassian_kemerink_müller_2017, title={Enhanced Electrical Conductivity of Molecularly p-Doped Poly(3-hexylthiophene) through Understanding the Correlation with Solid-State Order}, volume={50}, url={https://doi.org/10.1021/acs.macromol.7b00968}, DOI={10.1021/acs.macromol.7b00968}, abstractNote={Molecular p-doping of the conjugated polymer poly(3-hexylthiophene) (P3HT) with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) is a widely studied model system. Underlying structure–property relationships are poorly understood because processing and doping are often carried out simultaneously. Here, we exploit doping from the vapor phase, which allows us to disentangle the influence of processing and doping. Through this approach, we are able to establish how the electrical conductivity varies with regard to a series of predefined structural parameters. We demonstrate that improving the degree of solid-state order, which we control through the choice of processing solvent and regioregularity, strongly increases the electrical conductivity. As a result, we achieve a value of up to 12.7 S cm–1 for P3HT:F4TCNQ. We determine the F4TCNQ anion concentration and find that the number of (bound + mobile) charge carriers of about 10–4 mol cm–3 is not influenced by the degree of solid-state order. Thus, the observed increase in electrical conductivity by almost 2 orders of magnitude can be attributed to an increase in charge-carrier mobility to more than 10–1 cm2 V–1 s–1. Surprisingly, in contrast to charge transport in undoped P3HT, we find that the molecular weight of the polymer does not strongly influence the electrical conductivity, which highlights the need for studies that elucidate structure–property relationships of strongly doped conjugated polymers.}, number={20}, journal={Macromolecules}, publisher={American Chemical Society (ACS)}, author={Hynynen, Jonna and Kiefer, David and Yu, Liyang and Kroon, Renee and Munir, Rahim and Amassian, Aram and Kemerink, Martijn and Müller, Christian}, year={2017}, month={Oct}, pages={8140–8148} }
 @article{wadsworth_ashraf_abdelsamie_pont_little_moser_hamid_neophytou_zhang_amassian_et al._2017, title={Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents}, volume={2}, url={https://doi.org/10.1021/acsenergylett.7b00390}, DOI={10.1021/acsenergylett.7b00390}, abstractNote={With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed b...}, number={7}, journal={ACS Energy Letters}, publisher={American Chemical Society (ACS)}, author={Wadsworth, Andrew and Ashraf, Raja S. and Abdelsamie, Maged and Pont, Sebastian and Little, Mark and Moser, Maximilian and Hamid, Zeinab and Neophytou, Marios and Zhang, Weimin and Amassian, Aram and et al.}, year={2017}, month={Jul}, pages={1494–1500} }
 @article{mansour_kirmani_barlow_marder_amassian_2017, title={Hybrid Doping of Few-Layer Graphene via a Combination of Intercalation and Surface Doping}, volume={9}, url={https://doi.org/10.1021/acsami.7b02886}, DOI={10.1021/acsami.7b02886}, abstractNote={Surface molecular doping of graphene has been shown to modify its work function and increase its conductivity. However, the associated shifts in work function and increases in carrier concentration are highly coupled and limited by the surface coverage of dopant molecules on graphene. Here we show that few-layer graphene (FLG) can be doped using a hybrid approach, effectively combining surface doping by larger (metal-)organic molecules and intercalation of smaller molecules, such as Br2 and FeCl3, into the bulk. Intercalation tunes the carrier concentration more effectively, whereas surface doping of intercalated FLG can be used to tune its work function without reducing the carrier mobility. This multimodal doping approach yields a very high carrier density and tunable increase in the work function for FLG, demonstrating a new versatile platform for fabricating graphene-based contacts for electronic, optoelectronic, and photovoltaic applications.}, number={23}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Mansour, Ahmed E. and Kirmani, Ahmad R. and Barlow, Stephen and Marder, Seth R. and Amassian, Aram}, year={2017}, month={Jun}, pages={20020–20028} }
 @article{ugur_sheikh_munir_khan_barrit_amassian_laquai_2017, title={Improved Morphology and Efficiency of n–i–p Planar Perovskite Solar Cells by Processing with Glycol Ether Additives}, volume={2}, url={https://doi.org/10.1021/acsenergylett.7b00526}, DOI={10.1021/acsenergylett.7b00526}, abstractNote={Planar perovskite solar cells can be prepared without high-temperature processing steps typically associated with mesoporous device architectures; however, their efficiency has been lower, and producing high-quality perovskite films in planar devices has been challenging. Here, we report a modified two-step interdiffusion protocol suitable to preparing pinhole-free perovskite films with greatly improved morphology. This is achieved by simple addition of small amounts of glycol ethers to the preparation protocol. We unravel the impact the glycol ethers have on the perovskite film formation using in situ ultraviolet–visible absorbance and grazing incidence wide-angle X-ray scattering experiments. From these experiments we conclude that addition of glycol ethers changes the lead iodide to perovskite conversion dynamics and enhances the conversion efficiency, resulting in more compact polycrystalline films, and it creates micrometer-sized perovskite crystals vertically aligned across the photoactive layer. Co...}, number={9}, journal={ACS Energy Letters}, publisher={American Chemical Society (ACS)}, author={Ugur, Esma and Sheikh, Arif D. and Munir, Rahim and Khan, Jafar I. and Barrit, Dounya and Amassian, Aram and Laquai, Frédéric}, year={2017}, month={Sep}, pages={1960–1968} }
 @article{zhang_zhang_abdelsamie_shi_zhang_parker_jucov_timofeeva_amassian_bazan_et al._2017, title={Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores}, volume={29}, url={https://doi.org/10.1021/acs.chemmater.7b02665}, DOI={10.1021/acs.chemmater.7b02665}, abstractNote={Two intermediate-sized donor molecules, BBTz-X and BDT-X, have been synthesized by the Stille coupling between 4-(4,4-bis(2-ethylhexyl)-6-(trimethylstannyl)-4H-silolo[3,2-b:4,5-b′]dithiophen-2-yl)-7-(5′-hexyl-[2,2′-bithiophen]-5-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine and either 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diiodobenzo[1,2-d:4,5-d′]bis(thiazole) or 2,6-dibromo-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene, respectively. Both oxidation and reduction potentials for BBTz-X are anodically shifted relative to those for BDT-X, but the oxidation potential is more sensitive to the identity of the core; this is consistent with what is seen for DFT-calculated HOMO and LUMO energies and with a slightly blue-shifted absorption maximum for BBTz-X. Although DFT calculations, along with crystal structures of related compounds, suggest more planar molecular structures for BBTz-X than for BDT-X, film structures and the effects of various annealing processes on these films, as revealed by...}, number={18}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Zhang, Siyuan and Zhang, Junxiang and Abdelsamie, Maged and Shi, Qinqin and Zhang, Yadong and Parker, Timothy C. and Jucov, Evgheni V. and Timofeeva, Tatiana V. and Amassian, Aram and Bazan, Guillermo C. and et al.}, year={2017}, month={Sep}, pages={7880–7887} }
 @article{richter_delongchamp_amassian_2017, title={Morphology Development in Solution-Processed Functional Organic Blend Films: An In Situ Viewpoint}, volume={117}, url={https://doi.org/10.1021/acs.chemrev.6b00618}, DOI={10.1021/acs.chemrev.6b00618}, abstractNote={Solution-processed organic films are a facile route to high-speed, low cost, large-area deposition of electrically functional components (transistors, solar cells, emitters, etc.) that can enable a diversity of emerging technologies, from Industry 4.0, to the Internet of things, to point-of-use heath care and elder care. The extreme sensitivity of the functional performance of organic films to structure and the general nonequilibrium nature of solution drying result in extreme processing-performance correlations. In this Review, we highlight insights into the fundamentals of solution-based film deposition afforded by recent state-of-the-art in situ measurements of functional film drying. Emphasis is placed on multimodal studies that combine surface-sensitive X-ray scattering (GIWAXS or GISAXS) with optical characterization to clearly define the evolution of solute structure (aggregation, crystallinity, and morphology) with film thickness.}, number={9}, journal={Chemical Reviews}, publisher={American Chemical Society (ACS)}, author={Richter, Lee J. and DeLongchamp, Dean M. and Amassian, Aram}, year={2017}, month={May}, pages={6332–6366} }