@article{kim_schaefer_ma_zhao_turner_ghasemi_constantinou_so_yan_gadisa_et al._2019, title={The Critical Impact of Material and Process Compatibility on the Active Layer Morphology and Performance of Organic Ternary Solar Cells}, volume={9}, ISSN={["1614-6840"]}, url={https://doi.org/10.1002/aenm.201802293}, DOI={10.1002/aenm.201802293}, abstractNote={Abstract Although ternary solar cells (TSCs) offer a cost‐effective prospect to expand the absorption bandwidth of organic solar cells, only few TSCs have succeeded in surpassing the performance of binary solar cells (BSCs) primarily due to the complicated morphology of the ternary blends. Here, the key factors that create and limit the morphology and performance of the TSCs are elucidated. The origin of morphology formation is explored and the role of kinetic factors is investigated. The results reveal that the morphology of TSC blends considered in this study are characterized with either a single length‐scale or two length‐scale features depending on the composition of the photoactive polymers in the blend. This asymmetric morphology development reveals that TSC blend morphology critically depends on material compatibility and polymer solubility. Most interestingly, the fill factor (FF) of TSCs is found to linearly correlate with the relative standard deviation of the fullerene distribution at small lengths. This is the first time that such a correlation has been shown for ternary systems. The criteria that uniform sized and highly pure amorphous domains are accomplished through the correct kinetic path to obtain a high FF for TSCs are specifically elucidated. The findings provide a critical insight for the precise design and processing of TSCs.}, number={2}, journal={ADVANCED ENERGY MATERIALS}, author={Kim, Joo-Hyun and Schaefer, Charley and Ma, Tingxuan and Zhao, Jingbo and Turner, Johnathan and Ghasemi, Masoud and Constantinou, Iordania and So, Franky and Yan, He and Gadisa, Abay and et al.}, year={2019}, month={Jan} }
 @article{bauer_zhang_zhao_ye_kim_constantinou_yan_so_ade_yan_et al._2017, title={Comparing non-fullerene acceptors with fullerene in polymer solar cells: a case study with FTAZ and PyCNTAZ}, volume={5}, ISSN={["2050-7496"]}, url={https://doi.org/10.1039/C6TA10450A}, DOI={10.1039/c6ta10450a}, abstractNote={Non-fullerene acceptors (NFAs) are becoming a serious contender to fullerene-based electron acceptors in organic photovoltaics, due to their structural versatility and easily tunable optical and electronic properties.}, number={10}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, publisher={Royal Society of Chemistry (RSC)}, author={Bauer, Nicole and Zhang, Qianqian and Zhao, Jingbo and Ye, Long and Kim, Joo-Hyun and Constantinou, Iordania and Yan, Liang and So, Franky and Ade, Harald and Yan, He and et al.}, year={2017}, month={Mar}, pages={4886–4893} }
 @article{kim_gadisa_schaefer_yao_gautam_balar_ghasemi_constantinou_so_o'connor_et al._2017, title={Strong polymer molecular weight-dependent material interactions: impact on the formation of the polymer/fullerene bulk heterojunction morphology}, volume={5}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/C7TA03052E}, DOI={10.1039/c7ta03052e}, abstractNote={The morphological evolution is initiated by L–L or L–S phase separation (left) and further developed by molecular mobility, governed by polymer–solvent interactions which determine the final domain size of the BHJ layer (right).}, number={25}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={Kim, Joo-Hyun and Gadisa, Abay and Schaefer, Charley and Yao, Huifeng and Gautam, Bhoj R. and Balar, Nrup and Ghasemi, Masoud and Constantinou, Iordania and So, Franky and O'Connor, Brendan T. and et al.}, year={2017}, pages={13176–13188} }
 @article{klump_constantinou_lai_so_2017, title={Utilizing Forster resonance energy transfer to extend spectral response of PCDTBT:PCBM solar cells}, volume={42}, ISSN={["1878-5530"]}, DOI={10.1016/j.orgel.2016.12.010}, abstractNote={Light harvesting in the near-infrared part of the solar spectrum is important to achieve high efficiency polymer solar cells (PSCs). In this work, we demonstrate that we take an existing polymer:fullerene blend and extend its spectral response into the near-IR region by adding a small amount near-IR absorbing dye in the blend. The polymer studied in this work is Poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT). By adding only 2.5% squaraine dye to the blend, we were able to extend the spectral response of the resulting devices 100 nm into the near-IR spectral region. We show that the enhanced light harvesting is due to efficient Forster resonance energy transfer (FRET) between PCDTBT and the squaraine dye, resulting in an increase in power conversion efficiency. This type of ternary polymer solar cells is unique in that it allows the use of a small amount of selected dyes to extend light harvesting in infrared region.}, journal={ORGANIC ELECTRONICS}, author={Klump, Erik and Constantinou, Iordania and Lai, Tzung-Han and So, Franky}, year={2017}, month={Mar}, pages={87–92} }
 @article{constantinou_yi_shewmon_klump_peng_garakyaraghi_lo_reynolds_castellano_so_2017, title={effect of polymer-fullerene interaction on the dielectric properties of the blend}, volume={7}, number={13}, journal={Advanced Energy Materials}, author={Constantinou, I. and Yi, X. P. and Shewmon, N. T. and Klump, E. D. and Peng, C. and Garakyaraghi, S. and Lo, C. K. and Reynolds, J. R. and Castellano, F. N. and So, F.}, year={2017} }
 @article{gautam_younts_li_yan_danilov_klump_constantinou_so_you_ade_et al._2016, title={Charge photogeneration in organic photovoltaics: Role of hot versus cold charge-transfer excitons}, volume={6}, DOI={10.1002/aenm.201670002}, number={1}, journal={Advanced Energy Materials}, author={Gautam, B. R. and Younts, R. and Li, W. T. and Yan, L. and Danilov, E. and Klump, E. and Constantinou, I. and So, Franky and You, W. and Ade, H. and et al.}, year={2016} }
 @article{shewmon_yu_constantinou_klump_so_2016, title={Formation of Perovskite Heterostructures by Ion Exchange}, volume={8}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.6b10034}, abstractNote={Thin-film optoelectronic devices based on polycrystalline organolead-halide perovskites have recently become a topic of intense research. Single crystals of these materials have been grown from solution with electrical properties superior to those of polycrystalline films. In order to enable the development of more complex device architectures based on organolead-halide perovskite single crystals, we developed a process to form epitaxial layers of methylammonium lead iodide (MAPbI3) on methylammonium lead bromide (MAPbBr3) single crystals. The formation of the MAPbI3 layer is found to be dominated by the diffusion of halide ions, leading to a shift in the photoluminescence and absorption spectra. X-ray diffraction measurements confirm the single-crystal nature of the MAPbI3 layer, while carrier transport measurements show that the converted layer retains the high carrier mobility typical of single-crystal perovskite materials. Such heterostructures on perovskite single crystals open possibilities for new types of devices.}, number={48}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Shewmon, Nathan T. and Yu, Hyeonggeun and Constantinou, Iordania and Klump, Erik and So, Franky}, year={2016}, month={Dec}, pages={33273–33279} }
 @article{constantinou_shewmon_lo_deininger_reynolds_so_2016, title={Photodegradation of Metal Oxide Interlayers in Polymer Solar Cells}, volume={3}, ISSN={["2196-7350"]}, DOI={10.1002/admi.201600741}, abstractNote={The effect of 1 sun illumination for 24 h on encapsulated inverted organic photovoltaic devices is studied through a series of electrical and optical characterizations for donor/acceptor polymer solar cells based on poly(dithienogermole-alt-thienopyrrolodione)/[6,6]-phenyl C71 butyric acid methyl ester blends. Power conversion efficiency is significantly reduced after light exposure due to a 45% drop in the device fill factor and a 40% drop in both the open circuit voltage and short circuit current. The decrease in open circuit voltage is attributed to a reduction in the built-in field in the device due to photodegradation of the ZnO interlayer. The reduction in fill factor and short circuit current is shown to be due to the formation of an extraction barrier for hole collection as a result of photodegradation of the MoOx interlayer. Using a 400 nm long pass filter to block the UV light, device stability is significantly enhanced, resulting in a decrease in power conversion efficiency of less than 5% under the same operation conditions.}, number={23}, journal={ADVANCED MATERIALS INTERFACES}, author={Constantinou, Iordania and Shewmon, Nathan T. and Lo, Chi Kin and Deininger, James J. and Reynolds, John R. and So, Franky}, year={2016}, month={Dec} }