@article{yu_wang_kwok_zhou_yao_mukherjee_sergeev_hu_fu_ng_et al._2024, title={A polymer acceptor with double-decker configuration enhances molecular packing for high-performance all-polymer solar cells}, volume={8}, ISSN={["2542-4351"]}, DOI={10.1016/j.joule.2024.06.010}, number={8}, journal={JOULE}, author={Yu, Han and Wang, Yan and Kwok, Chung Hang and Zhou, Rongkun and Yao, Zefan and Mukherjee, Subhrangsu and Sergeev, Aleksandr and Hu, Haixia and Fu, Yuang and Ng, Ho Ming and et al.}, year={2024}, month={Aug} }
 @article{pacalaj_dong_ramirez_mackenzie_hosseini_bittrich_heger_kaienburg_mukherjee_wu_et al._2024, title={From generation to collection - impact of deposition temperature on charge carrier dynamics of high-performance vacuum-processed organic solar cells}, volume={10}, ISSN={["1754-5706"]}, DOI={10.1039/d4ee03623a}, abstractNote={Vacuum-processed organic solar cells (VP-OSCs) possess many advantages for scalability. However, as the academic community focusses on high performing solution-processed OSCs, detailed studies about the relation between morphology and device...}, journal={ENERGY & ENVIRONMENTAL SCIENCE}, author={Pacalaj, Richard Adam and Dong, Yifan and Ramirez, Ivan and Mackenzie, Roderick C. I. and Hosseini, Seyed Mehrdad and Bittrich, Eva and Heger, Julian Eliah and Kaienburg, Pascal and Mukherjee, Subhrangsu and Wu, Jiaying and et al.}, year={2024}, month={Oct} }
 @article{wang_guo_liu_shu_han_ding_mukherjee_zhang_yip_yi_et al._2024, title={The role of interfacial donor-acceptor percolation in efficient and stable all-polymer solar cells}, volume={15}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-024-45455-0}, abstractNote={AbstractPolymerization of Y6-type acceptor molecules leads to bulk-heterojunction organic solar cells with both high power-conversion efficiency and device stability, but the underlying mechanism remains unclear. Here we show that the exciton recombination dynamics of polymerized Y6-type acceptors (Y6-PAs) strongly depends on the degree of aggregation. While the fast exciton recombination rate in aggregated Y6-PA competes with electron-hole separation at the donor–acceptor (D–A) interface, the much-suppressed exciton recombination rate in dispersed Y6-PA is sufficient to allow efficient free charge generation. Indeed, our experimental results and theoretical simulations reveal that Y6-PAs have larger miscibility with the donor polymer than Y6-type small molecular acceptors, leading to D–A percolation that effectively prevents the formation of Y6-PA aggregates at the interface. Besides enabling high charge generation efficiency, the interfacial D–A percolation also improves the thermodynamic stability of the blend morphology, as evident by the reduced device “burn-in” loss upon solar illumination.}, number={1}, journal={NATURE COMMUNICATIONS}, author={Wang, Zhen and Guo, Yu and Liu, Xianzhao and Shu, Wenchao and Han, Guangchao and Ding, Kan and Mukherjee, Subhrangsu and Zhang, Nan and Yip, Hin-Lap and Yi, Yuanping and et al.}, year={2024}, month={Feb} }
 @article{mukherjee_gann_nahid_mcafee_herzing_delongchamp_ade_2021, title={Orientational Ordering within Semiconducting Polymer Fibrils}, volume={31}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.202102522}, abstractNote={AbstractDue to a general paucity of suitable characterization methods, the internal orientational ordering of polymer fibrils has rarely been measured despite its importance particularly for semi‐conducting polymers. An emerging tool with sensitivity to bond orientation is polarized resonant soft X‐ray scattering (P‐RSoXS). Here, P‐RSoXS reveals the molecular arrangement within fibrils (if type I or type II fibrils), the extent of orientation in the fibril crystal, and an explicit crystal‐amorphous interphase. Neat films as well as binary blends with a fullerene derivative are characterized for three different polymers, that are prototypical materials widely used in organic electronics applications. Anisotropic P‐RSoXS patterns reveal two different fibril types. Analysis of the q‐dependence of the anisotropy from simulated and experimental scattering patterns reveal that neat polymer fibrillar systems likely comprise more than two phases, with the third phase in addition to crystal and amorphous likely being an interphase with distinct density and orientation. Intriguingly, the fibril type correlates to the H‐ or J‐aggregation signature in ultraviolet‐visible (UV–vis) spectroscopy, revealing insight into the fibril formation. Together, the results will open the door to develop more sophisticated structure‐function relationships between chemical design, fibril type, formation pathways and kinetics, interfacial ordering, and eventually device functions.}, number={28}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Mukherjee, Subhrangsu and Gann, Eliot and Nahid, Masrur Morshed and McAfee, Terry and Herzing, Andrew A. and DeLongchamp, Dean M. and Ade, Harald}, year={2021}, month={Jul} }
 @article{mukherjee_jiao_ade_2016, title={Charge Creation and Recombination in Multi-Length Scale Polymer:Fullerene BHJ Solar Cell Morphologies}, volume={6}, ISSN={["1614-6840"]}, DOI={10.1002/aenm.201600699}, abstractNote={While the extremes in organic photovoltaic bulk heterojunction morphology (finely mixed or large pure domains) are easily understood and known to be unfavorable, efficient devices often exhibit a complex multi‐length scale, multi‐phase morphology. The impact of such multiple length scales and their respective purities and volume fractions on device performance remains unclear. Here, the average spatial composition variations, i.e., volume‐average purities, are quantified at multiple size scales to elucidate their effect on charge creation and recombination in a complex, multi‐length scale polymer:fullerene system (PBDTTPD:PC71BM). The apparent domain size as observed in TEM is not a causative parameter. Instead, a linear relationship is found between average purity at length scales <50 nm and device fill‐factor. Our findings show that a high volume fraction of pure phases at the smallest length scales is required in multi‐length scale systems to aid charge creation and diminish recombination in polymer:fullerene solar cells.}, number={18}, journal={ADVANCED ENERGY MATERIALS}, author={Mukherjee, Subhrangsu and Jiao, Xuechen and Ade, Harald}, year={2016}, month={Sep} }
 @article{li_ye_zhao_zhang_mukherjee_ade_hou_2016, title={Energy-Level Modulation of Small-Molecule Electron Acceptors to Achieve over 12% Efficiency in Polymer Solar Cells}, volume={28}, ISSN={["1521-4095"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=MEDLINE&KeyUT=MEDLINE:27606970&KeyUID=MEDLINE:27606970}, DOI={10.1002/adma.201602776}, abstractNote={Fine energy-level modulations of small-molecule acceptors (SMAs) are realized via subtle chemical modifications on strong electron-withdrawing end-groups. The two new SMAs (IT-M and IT-DM) end-capped by methyl-modified dicycanovinylindan-1-one exhibit upshifted lowest unoccupied molecular orbital (LUMO) levels, and hence higher open-circuit voltages can be observed in the corresponding devices. Finally, a top power conversion efficiency of 12.05% is achieved.}, number={42}, journal={ADVANCED MATERIALS}, author={Li, Sunsun and Ye, Long and Zhao, Wenchao and Zhang, Shaoqing and Mukherjee, Subhrangsu and Ade, Harald and Hou, Jianhui}, year={2016}, month={Nov}, pages={9423-+} }
 @article{ye_zhao_li_mukherjee_carpenter_awartani_jiao_hou_ade_2017, title={High-Efficiency Nonfullerene Organic Solar Cells: Critical Factors that Affect Complex Multi-Length Scale Morphology and Device Performance}, volume={7}, ISSN={["1614-6840"]}, url={https://publons.com/wos-op/publon/5290907/}, DOI={10.1002/aenm.201602000}, abstractNote={Organic solar cells (OSCs) made of donor/acceptor bulk‐heterojunction active layers have been of widespread interest in converting sunlight to electricity. Characterizing of the complex morphology at multiple length scales of polymer:nonfullerene small molecular acceptor (SMA) systems remains largely unexplored. Through detailed characterizations (hard/soft X‐ray scattering) of the record‐efficiency polymer:SMA system with a close analog, quantitative morphological parameters are related to the device performance parameters and fundamental morphology–performance relationships that explain why additive use and thermal annealing are needed for optimized performance are established. A linear correlation between the average purity variations at small length scale (≈10 nm) and photovoltaic device characteristics across all processing protocols is observed in ≈12%‐efficiency polymer:SMA systems. In addition, molecular interactions as reflected by the estimated Flory–Huggins interaction parameters are used to provide context of the room temperature morphology results. Comparison with results from annealed devices suggests that the two SMA systems compared show upper and lower critical solution temperature behavior, respectively. The in‐depth understanding of the complex multilength scale nonfullerene OSC morphology may guide the device optimization and new materials development and indicates that thermodynamic properties of materials systems should be studied in more detail to aid in designing optimized protocols efficiently.}, number={7}, journal={ADVANCED ENERGY MATERIALS}, author={Ye, Long and Zhao, Wenchao and Li, Sunsun and Mukherjee, Subhrangsu and Carpenter, Joshua H. and Awartani, Omar and Jiao, Xuechen and Hou, Jianhui and Ade, Harald}, year={2017}, month={Apr} }
 @article{ro_downing_engmann_herzing_delongchamp_richter_mukherjee_ade_abdelsamie_jagadamma_et al._2016, title={Morphology changes upon scaling a high-efficiency, solution-processed solar cell}, volume={9}, ISSN={["1754-5706"]}, DOI={10.1039/c6ee01623e}, abstractNote={Optimized spin-coating and blade-coating are found to produce similar performance yet notably different morphologies.}, number={9}, journal={ENERGY & ENVIRONMENTAL SCIENCE}, author={Ro, Hyun Wook and Downing, Jonathan M. and Engmann, Sebastian and Herzing, Andrew A. and DeLongchamp, Dean M. and Richter, Lee J. and Mukherjee, Subhrangsu and Ade, Harald and Abdelsamie, Maged and Jagadamma, Lethy K. and et al.}, year={2016}, pages={2835–2846} }
 @article{capelli_mahne_koshmak_giglia_doyle_mukherjee_nannarone_pasquali_2016, title={Quantitative resonant soft x-ray reflectivity of ultrathin anisotropic organic layers: Simulation and experiment of PTCDA on Au}, volume={145}, ISSN={["1089-7690"]}, DOI={10.1063/1.4956452}, abstractNote={Resonant soft X-ray reflectivity at the carbon K edge, with linearly polarized light, was used to derive quantitative information of film morphology, molecular arrangement, and electronic orbital anisotropies of an ultrathin 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) film on Au(111). The experimental spectra were simulated by computing the propagation of the electromagnetic field in a trilayer system (vacuum/PTCDA/Au), where the organic film was treated as an anisotropic medium. Optical constants were derived from the calculated (through density functional theory) absorption cross sections of the single molecule along the three principal molecular axes. These were used to construct the dielectric tensor of the film, assuming the molecules to be lying flat with respect to the substrate and with a herringbone arrangement parallel to the substrate plane. Resonant soft X-ray reflectivity proved to be extremely sensitive to film thickness, down to the single molecular layer. The best agreement between simulation and experiment was found for a film of 1.6 nm, with flat laying configuration of the molecules. The high sensitivity to experimental geometries in terms of beam incidence and light polarization was also clarified through simulations. The optical anisotropies of the organic film were experimentally determined and through the comparison with calculations, it was possible to relate them to the orbital symmetry of the empty electronic states.}, number={2}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Capelli, R. and Mahne, N. and Koshmak, K. and Giglia, A. and Doyle, B. P. and Mukherjee, S. and Nannarone, S. and Pasquali, L.}, year={2016}, month={Jul} }
 @article{gann_collins_tang_tumbleston_mukherjee_ade_2016, title={Origins of polarization-dependent anisotropic X-ray scattering from organic thin films}, volume={23}, ISSN={["1600-5775"]}, DOI={10.1107/s1600577515019074}, abstractNote={Organic thin films that have no overall in-plane directional ordering often nonetheless produce anisotropic scattering patterns that rotate with the polarization of incident resonant X-rays. Isotropic symmetry is broken by local correlations between molecular orientation and domain structure. Such examples of molecular alignment at domain interfaces and within the bulk of domains, which are both critical to fields such as organic electronics, are simulated and compared with experimental scattering. Anisotropic scattering patterns are found to allow unambiguous identification of the mechanism of local molecular orientation correlations and, as such, promise to be both distinct and complementary to isotropic scattering intensity as a general measure of thin film microstructure.}, journal={JOURNAL OF SYNCHROTRON RADIATION}, author={Gann, Eliot and Collins, Brian A. and Tang, Maolong and Tumbleston, John R. and Mukherjee, Subrangsu and Ade, Harald}, year={2016}, month={Jan}, pages={219–227} }
 @article{mukherjee_proctor_bazan_nguyen_ade_2015, title={Significance of average domain purity and mixed domains on the photovoltaic performance of high-efficiency solution-processed small-molecule bhj solar cells}, volume={5}, DOI={10.1002/aenm.201570111}, abstractNote={In article 1500877, Thuc-Quyen Nguyen, Harald Ade, and co-workers demonstrate the connection between device performance and morphological parameters in organic photovoltaics. The results demonstrate the complex correlation between domain purity, size, and molecular ordering, and highlight the requirement of achieving sufficient average phase purity of donor and acceptor domains to diminish charge recombination losses in solution-processed small-molecule bulk heterojunction solar cells.}, number={21}, journal={Advanced Energy Materials}, author={Mukherjee, S. and Proctor, C. M. and Bazan, G. C. and Nguyen, T. Q. and Ade, Harald}, year={2015} }
 @article{zhao_li_zhang_zhang_lai_jiang_mu_li_chan_hunt_et al._2015, title={The influence of spacer units on molecular properties and solar cell performance of non-fullerene acceptors}, volume={3}, ISSN={["2050-7496"]}, DOI={10.1039/c5ta05339k}, abstractNote={The position of methyl groups causes a dramatic change in molecular properties and solar cell performance.}, number={40}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Zhao, Jingbo and Li, Yunke and Zhang, Jianquan and Zhang, Lu and Lai, Joshua Yuk Lin and Jiang, Kui and Mu, Cheng and Li, Zhengke and Chan, Chun Lam Clement and Hunt, Adrian and et al.}, year={2015}, pages={20108–20112} }
 @article{huang_wen_mukherjee_ade_kramer_bazan_2014, title={High-Molecular-Weight Insulating Polymers Can Improve the Performance of Molecular Solar Cells}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201400497}, abstractNote={The addition of small quantities of polystyrene (PS) is a simple and economically viable process that improves the power conversion efficiency of one of the most efficient small molecule donors. Addition of PS increases the solution viscosity, thereby providing thicker layers, and allows the formation of a desirable bulk heterojunction morphology. Moreover, the PS spontaneously accumulates as phase separated domains, away from the electrodes, so as not to interfere with charge extraction.}, number={24}, journal={ADVANCED MATERIALS}, author={Huang, Ye and Wen, Wen and Mukherjee, Subhrangsu and Ade, Harald and Kramer, Edward J. and Bazan, Guillermo C.}, year={2014}, month={Jun}, pages={4168–4172} }
 @article{mukherjee_proctor_tumbleston_bazan_nguyen_ade_2015, title={Importance of Domain Purity and Molecular Packing in Efficient Solution-Processed Small-Molecule Solar Cells}, volume={27}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201404388}, abstractNote={Connections are delineated between solar-cell performance, charge-carrier mobilities, and morphology in a highperformance molecular solar cell. The observations show that maximizing the relative phase purity and structural order while simultaneously limiting the domain size may be essential for achieving optimal solar-cell performances in solution-processed small-molecule solar cells .}, number={6}, journal={ADVANCED MATERIALS}, author={Mukherjee, Subhrangsu and Proctor, Christopher M. and Tumbleston, John R. and Bazan, Guillermo C. and Nguyen, Thuc-Quyen and Ade, Harald}, year={2015}, month={Feb}, pages={1105–1111} }
 @article{he_mukherjee_watkins_chen_qin_thomsen_ade_mcneill_2014, title={Influence of Fluorination and Molecular Weight on the Morphology and Performance of PTB7:PC71BM Solar Cells}, volume={118}, ISSN={["1932-7447"]}, DOI={10.1021/jp501222w}, abstractNote={The device performance and microstructure of a series of PTB7-based polymers with varied molecular weight and degree of fluorination are investigated. Although the energy level of the highest occupied molecular orbital is found to increase with degree of fluorination, a strong relative molecular weight dependence of device performance dominates any underlying fluorination-dependent trend on overall performance. Microstructural investigation using a combination of X-ray techniques reveals a striking effect of polymer molecular characteristics on film morphology, with the size of PC71BM domains systematically decreasing with increasing polymer molecular weight. Furthermore, the relative purity of the mixed PTB7:PC71BM domain is found to systematically decrease with increasing molecular weight. When domain sizes with and without the use of the solvent additive diiodooctane (DIO) are compared, the effectiveness of DIO in reducing PC71BM domain sizes is also found to be strongly dependent on the molecular weig...}, number={19}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={He, Xiaoxi and Mukherjee, Subhrangsu and Watkins, Scott and Chen, Ming and Qin, Tianshi and Thomsen, Lars and Ade, Harald and McNeill, Christopher R.}, year={2014}, month={May}, pages={9918–9929} }
 @article{love_collins_nagao_mukherjee_ade_bazan_nguyen_2014, title={Interplay of Solvent Additive Concentration and Active Layer Thickness on the Performance of Small Molecule Solar Cells}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201402403}, abstractNote={A relationship between solvent additive concentration and active layer thickness in small-molecule solar cells is investigated. Specifically, the additive concentration must scale with the amount of semiconductor material and not as absolute concentration in solution. Devices with a wide range of active layers with thickness up to 200 nm can readily achieve efficiencies close to 6% when the right concentration of additive is used.}, number={43}, journal={ADVANCED MATERIALS}, author={Love, John A. and Collins, Samuel D. and Nagao, Ikuhiro and Mukherjee, Subhrangsu and Ade, Harald and Bazan, Guillermo C. and Nguyen, Thuc-Quyen}, year={2014}, month={Nov}, pages={7308–7316} }