@article{zeng_ma_pan_chen_ma_zhao_zhang_kim_shang_luo_et al._2021, title={A Chlorinated Donor Polymer Achieving High-Performance Organic Solar Cells with a Wide Range of Polymer Molecular Weight}, volume={6}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.202102413}, abstractNote={In the field of non-fullerene organic solar cells (OSCs), compared to the rapid development of non-fullerene acceptors, the progress of high-performance donor polymers is relatively slow. The property and performance of donor polymers in OSCs are often sensitive to the molecular weight of the polymers. In this study, a chlorinated donor polymer named D18-Cl is reported, which can achieve high performance with a wide range of polymer molecular weight. The devices based on D18-Cl show a higher open-circuit voltage (VOC) due to the slightly deeper energy levels and an outstanding short-circuit current density (JSC) owing to the appropriate long periods of blend films and less ([6,6]-phenyl-C71-butyric acid methyl ester) (PC71BM) in mixed domains, leading to the higher efficiency of 17.97% than those of the D18-based devices (17.21%). Meanwhile, D18-Cl can achieve high efficiencies (17.30–17.97%) when its number-averaged molecular weight (Mn) is ranged from 45 to 72 kDa. In contrast, the D18-based devices only exhibit relatively high efficiencies in a narrow Mn range of ≈70 kDa. Such property and performance make D18-Cl a promising donor polymer for scale-up and low-cost production.}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Zeng, Anping and Ma, Xiaoling and Pan, Mingao and Chen, Yuzhong and Ma, Ruijie and Zhao, Heng and Zhang, Jianquan and Kim, Ha Kyung and Shang, Ao and Luo, Siwei and et al.}, year={2021}, month={Jun} }
 @article{hu_li_zhang_peng_ma_xin_huang_ma_jiang_zhang_et al._2018, title={Effect of Ring-Fusion on Miscibility and Domain Purity: Key Factors Determining the Performance of PDI-Based Nonfullerene Organic Solar Cells}, volume={8}, ISSN={["1614-6840"]}, DOI={10.1002/aenm.201800234}, abstractNote={Compared to the rapid development of nonfullerene organic solar cells (OSCs) based on the state-of-the-art indacenodithiophene (IDT)-based small molecule acceptors (SMAs), the progress for perylene diimide (PDI)-based electron acceptors has lagged behind owing to the lack of understanding on the structure–morphology–performance relationship of PDI SMAs. Given the ease of synthesis for PDIs and their high intrinsic electron mobility, it is crucial to identify key material parameters that influence the polymer:PDI blend morphology and to develop rational approaches for molecular design toward high-performance PDI-based SMAs. In this study, three pairs of PDI-based SMAs with and without ring-fusion are investigated and it is found that ring-fusion and domain purity are the key structural and morphological factors determining the fill factors (FFs) and efficiencies of PDI-based nonfullerene OSCs. This data shows that nonfullerene OSCs based on the ring-fused PDI-based SMAs exhibit much higher average domain purity and thus increased charge mobilities, which lead to enhanced FFs compared to those solar cells based on nonfused PDIs. This is explained by higher Florry Huggins interaction parameters as observed by melting point depression measurements. This study suggests that increasing repulsive molecular interactions to lower the miscibility between the polymer donor and PDI acceptor is the key to improve the FF and performance of PDI-based devices.}, number={26}, journal={ADVANCED ENERGY MATERIALS}, author={Hu, Huawei and Li, Yunke and Zhang, Jianquan and Peng, Zhengxing and Ma, Lik-kuen and Xin, Jingming and Huang, Jiachen and Ma, Tingxuan and Jiang, Kui and Zhang, Guangye and et al.}, year={2018}, month={Sep} }
 @article{zhang_guo_ma_ade_hou_2015, title={A Large-Bandgap Conjugated Polymer for Versatile Photovoltaic Applications with High Performance}, volume={27}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201502110}, abstractNote={A new copolymer PM6 based on fluorothienyl-substituted benzodithiophene is synthesized and characterized. The inverted polymer solar cells based on PM6 exhibit excellent performance with Voc of 0.98 V and power conversion efficiency (PCE) of 9.2% for a thin-film thickness of 75 nm. Furthermore, the single-junction semitransparent device shows a high PCE of 5.7%.}, number={31}, journal={ADVANCED MATERIALS}, author={Zhang, Maojie and Guo, Xia and Ma, Wei and Ade, Harald and Hou, Jianhui}, year={2015}, month={Aug}, pages={4655–4660} }
 @article{ma_reinspach_zhou_diao_mcafee_mannsfeld_bao_ade_2015, title={Tuning Local Molecular Orientation-Composition Correlations in Binary Organic Thin Films by Solution Shearing}, volume={25}, ISSN={["1616-3028"]}, DOI={10.1002/adfm.201500468}, abstractNote={A general impact of solution shearing on molecular orientation correlation is observed in polymer:fullerene organic solar cells in which one of the components forms fi brils or aggregates. Further investigation with polarized soft X-ray scattering reveals that solution shearing induces more face-to-face orientation relative to the interface of two components compared to spincoating. This impact is shearing speed dependent, that is, slow shearing speed can induce more face-to-face orientation than a fast shearing speed. These results demonstrate that solution shearing is an effective method to control the relative molecular orientation. Solution shearing can also modify the domain size and average composition variations.}, number={21}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Ma, Wei and Reinspach, Julia and Zhou, Yan and Diao, Ying and McAfee, Terry and Mannsfeld, Stefan C. B. and Bao, Zhenan and Ade, Harald}, year={2015}, month={Jun}, pages={3131–3137} }
 @article{zhang_guo_ma_ade_hou_2014, title={A Polythiophene Derivative with Superior Properties for Practical Application in Polymer Solar Cells}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201401494}, abstractNote={A polythiophene derivative called PDCBT, which has a backbone of thiophene units and just carboxylate functional groups to modulate its properties, exhibits properties superior to those of poly(3-hexylthiophene), the classic polythiophene derivative, when used as an electron donor in polymer solar cells (PSCs). The best device, based on PDCBT/PC71BM (1:1), develops a good power conversion efficiency of 7.2%. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.}, number={33}, journal={ADVANCED MATERIALS}, author={Zhang, Maojie and Guo, Xia and Ma, Wei and Ade, Harald and Hou, Jianhui}, year={2014}, month={Sep}, pages={5880–5885} }
 @article{liu_zhao_li_mu_ma_hu_jiang_lin_ade_yan_2014, title={Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells}, volume={5}, ISSN={["2041-1723"]}, DOI={10.1038/ncomms6293}, abstractNote={Although the field of polymer solar cell has seen much progress in device performance in the past few years, several limitations are holding back its further development. For instance, current high-efficiency (>9.0%) cells are restricted to material combinations that are based on limited donor polymers and only one specific fullerene acceptor. Here we report the achievement of high-performance (efficiencies up to 10.8%, fill factors up to 77%) thick-film polymer solar cells for multiple polymer:fullerene combinations via the formation of a near-ideal polymer:fullerene morphology that contains highly crystalline yet reasonably small polymer domains. This morphology is controlled by the temperature-dependent aggregation behaviour of the donor polymers and is insensitive to the choice of fullerenes. The uncovered aggregation and design rules yield three high-efficiency (>10%) donor polymers and will allow further synthetic advances and matching of both the polymer and fullerene materials, potentially leading to significantly improved performance and increased design flexibility.}, journal={NATURE COMMUNICATIONS}, author={Liu, Yuhang and Zhao, Jingbo and Li, Zhengke and Mu, Cheng and Ma, Wei and Hu, Huawei and Jiang, Kui and Lin, Haoran and Ade, Harald and Yan, He}, year={2014}, month={Nov} }
 @article{zhang_guo_ma_zhang_huo_ade_hou_2014, title={An Easy and Effective Method to Modulate Molecular Energy Level of the Polymer Based on Benzodithiophene for the Application in Polymer Solar Cells}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201304631}, abstractNote={Attaching meta-alkoxy-phenyl groups as conjugated side chains is an easy and effective way to modulate the molecular energy level of D-A polymer for photovoltaic application, and the polymer solar cells based on the polymer consisting meta-alkoxy-phenyl groups as conjugated side chain, PBT-OP, shows an enhanced open circuit voltage and thus higher efficiency of 7.50%, under the illumination of AM 1.5G, 100 mW/cm(2) .}, number={13}, journal={ADVANCED MATERIALS}, author={Zhang, Maojie and Guo, Xia and Ma, Wei and Zhang, Shaoqing and Huo, Lijun and Ade, Harald and Hou, Jianhui}, year={2014}, month={Apr}, pages={2089–2095} }
 @article{guo_zhang_ma_ye_zhang_liu_ade_huang_hou_2014, title={Enhanced Photovoltaic Performance by Modulating Surface Composition in Bulk Heterojunction Polymer Solar Cells Based on PBDTTT-C-T/PC71BM}, volume={26}, ISSN={["1521-4095"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903160839&partnerID=MN8TOARS}, DOI={10.1002/adma.201400411}, abstractNote={For the blend film of PBDTTT-C-T:PC71 BM, the use of 1,8-diiodooctane as the solvent additive enriches the polymer at the top surface, so that a power conversion efficiency of 9.13% is recorded in the inverted polymer solar cell based on the blend, which is much higher than that of the device with conventional structure.}, number={24}, journal={ADVANCED MATERIALS}, author={Guo, Xia and Zhang, Maojie and Ma, Wei and Ye, Long and Zhang, Shaoqing and Liu, Shengjian and Ade, Harald and Huang, Fei and Hou, Jianhui}, year={2014}, month={Jun}, pages={4043–4049} }
 @article{zhou_kurosawa_ma_guo_fang_vandewal_diao_wang_yan_reinspach_et al._2014, title={High Performance All-Polymer Solar Cell via Polymer Side-Chain Engineering}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201306242}, abstractNote={Acknowledge support from the Office of Naval Research (N00014-14-1-0142), KAUST Center for Advanced Molecular Photovoltaics at Stanford and the Stanford Global Climate and Energy Program, NSF DMR-1303742 and the National Natural Science Foundation of China (Projects 21174004 and 21222403). Soft X-ray characterization and analysis by NCSU supported by the U.S. Department of Energy, Office of Science, Basic Energy Science, Division of Materials Science and Engineering under Contract DE-FG02-98ER45737. Soft X-ray data was acquired at beamlines 11.0.1.2 at the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231. We thank Professor Michael D. McGehee, Dr. George F. Burkhard and Dr. Eric T. Hoke for their help in discussion of the recombination mechanism.}, number={22}, journal={ADVANCED MATERIALS}, author={Zhou, Yan and Kurosawa, Tadanori and Ma, Wei and Guo, Yikun and Fang, Lei and Vandewal, Koen and Diao, Ying and Wang, Chenggong and Yan, Qifan and Reinspach, Julia and et al.}, year={2014}, month={Jun}, pages={3767–3772} }
 @article{mu_liu_ma_jiang_zhao_zhang_chen_wei_yi_wang_et al._2014, title={High-Efficiency All-Polymer Solar Cells Based on a Pair of Crystalline Low-Bandgap Polymers}, volume={26}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201402473}, abstractNote={All-polymer solar cells based on a pair of crystalline low-bandgap polymers (NT and N2200) are demonstrated to achieve a high short-circuit current density of 11.5 mA cm-2 and a power conversion efficiency of up to 5.0% under the standard AM1.5G spectrum with one sun intensity. The high performance of these NT:N2200-based cells can be attributed to the low optical bandgaps of the polymers and the reasonably high and balanced electron and hole mobilities of the NT:N2200 blends due to the crystalline nature of the two polymers.}, number={42}, journal={ADVANCED MATERIALS}, author={Mu, Cheng and Liu, Peng and Ma, Wei and Jiang, Kui and Zhao, Jingbo and Zhang, Kai and Chen, Zhihua and Wei, Zhanhua and Yi, Ya and Wang, Jiannong and et al.}, year={2014}, month={Nov}, pages={7224–7230} }
 @article{ma_tumbleston_ye_wang_hou_ade_2014, title={Quantification of Nano- and Mesoscale Phase Separation and Relation to Donor and Acceptor Quantum Efficiency, J(SC), and FF in Polymer:Fullerene Solar Cells}, volume={26}, ISSN={["1521-4095"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903724646&partnerID=MN8TOARS}, DOI={10.1002/adma.201400216}, abstractNote={Two characteristic length scales are revealed and quantified in a complex hierarchical polymer–fullerene blend by combining different X-ray scattering techniques. Anti-correlated composition variations between meso- and nanoscale separation are observed and impacted by the solvent mixture. Due to competition between the impact of the two length scales, the relation to device performance is complex and an ideal morphology is yet to be delineated.}, number={25}, journal={ADVANCED MATERIALS}, author={Ma, Wei and Tumbleston, John R. and Ye, Long and Wang, Cheng and Hou, Jianhui and Ade, Harald}, year={2014}, month={Jul}, pages={4234–4241} }
 @article{tumbleston_collins_yang_stuart_gann_ma_you_ade_2014, title={The influence of molecular orientation on organic bulk heterojunction solar cells}, volume={8}, ISSN={["1749-4893"]}, DOI={10.1038/nphoton.2014.55}, number={5}, journal={NATURE PHOTONICS}, author={Tumbleston, John R. and Collins, Brian A. and Yang, Liqiang and Stuart, Andrew C. and Gann, Eliot and Ma, Wei and You, Wei and Ade, Harald}, year={2014}, month={May}, pages={385–391} }
 @article{ma_ye_zhang_hou_ade_2013, title={Competition between morphological attributes in the thermal annealing and additive processing of polymer solar cells}, volume={1}, number={33}, journal={Journal of Materials Chemistry C}, author={Ma, W. and Ye, L. and Zhang, S. Q. and Hou, J. H. and Ade, H.}, year={2013}, pages={5023–5030} }
 @article{ma_tumbleston_wang_gann_huang_ade_2013, title={Domain Purity, Miscibility, and Molecular Orientation at Donor/Acceptor Interfaces in High Performance Organic Solar Cells: Paths to Further Improvement}, volume={3}, ISSN={["1614-6840"]}, DOI={10.1002/aenm.201200912}, abstractNote={Domain purity and interface structure are known to be critical for fullerene-based bulk heterojunction (BHJ) solar cells, yet have been very difficult to study. Using novel soft X-ray tools, we delineate the importance of these parameters by comparing high performance cells based on a novel naphtha[1,2-c:5,6-c]bis[1,2,5]thiadiazole (NT) material to cells based on a 2,1,3-benzothiadiazole (BT) analogue. BT-based devices exhibit ∼15 nm, mixed domains that differ in composition by at most 22%, causing substantial bimolecular recombination. In contrast, NT-based devices have more pure domains that are >80 nm in size, yet the polymer-rich phase still contains at least 22% fullerene. Power conversion efficiency >6% is achieved for NT devices despite a domain size much larger than the nominal exciton diffusion length due to a favourable trade-off in the mixed domain between exciton harvesting, charge transport, and bimolecular recombination. The miscibility of the fullerene with the NT and BT polymer is measured and correlated to the purity in devices. Importantly, polarized x-ray scattering reveals preferential face-on orientation of the NT polymer relative to the PCBM-rich domains. Such ordering has previously not been observed in fullerene-based solar cells and is shown here to be possibly a controlling or contributing factor to high performance.}, number={7}, journal={ADVANCED ENERGY MATERIALS}, author={Ma, Wei and Tumbleston, John R. and Wang, Ming and Gann, Eliot and Huang, Fei and Ade, Harald}, year={2013}, month={Jul}, pages={864–872} }
 @article{qian_ma_li_guo_zhang_ye_ade_tan_hou_2013, title={Molecular Design toward Efficient Polymer Solar Cells with High Polymer Content}, volume={135}, ISSN={["1520-5126"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84878954003&partnerID=MN8TOARS}, DOI={10.1021/ja402971d}, abstractNote={A novel polythiophene derivative, PBT1, was designed, synthesized, and applied in polymer solar cells (PSCs). This work provides a successful example of using molecular structure as a tool to realize optimal photovoltaic performance with high polymer content, thus enabling the realization of efficient photoabsorption in very thin films. As a result, an efficiency of 6.88% was recorded in a PSC with a 75 nm active layer.}, number={23}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Qian, Deping and Ma, Wei and Li, Zhaojun and Guo, Xia and Zhang, Shaoqing and Ye, Long and Ade, Harald and Tan, Zhan'ao and Hou, Jianhui}, year={2013}, month={Jun}, pages={8464–8467} }
 @article{wu_li_ma_huang_huo_guo_zhang_ade_hou_2013, title={PDT-S-T: A New Polymer with Optimized Molecular Conformation for Controlled Aggregation and pi-pi Stacking and Its Application in Efficient Photovoltaic Devices}, volume={25}, ISSN={["1521-4095"]}, DOI={10.1002/adma.201301174}, abstractNote={The correlation among molecular conformation, the crystallinity of the morphology, propensity for π-π stacking, J- versus H-aggregation, and photovoltaic performance have been studied based on two newly designed polymers, PBDTTT-S-T and PDT-S-T. The results show that more linear backbone structure is helpful to improve photovoltaic properties of the polymer, and therefore, molecular conformation should be considered for molecular design of photovoltaic polymers.}, number={25}, journal={ADVANCED MATERIALS}, author={Wu, Yue and Li, Zhaojun and Ma, Wei and Huang, Ye and Huo, Lijun and Guo, Xia and Zhang, Maojie and Ade, Harald and Hou, Jianhui}, year={2013}, month={Jul}, pages={3449–3455} }
 @article{ye_zhang_ma_fan_guo_huang_ade_hou_2012, title={From Binary to Ternary Solvent: Morphology Fine-tuning of D/A Blends in PDPP3T-based Polymer Solar Cells}, volume={24}, ISSN={["1521-4095"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84870872663&partnerID=MN8TOARS}, DOI={10.1002/adma.201202855}, abstractNote={For the PDPP3T/PCBM system investigated here, atomic force microscopy, resonant soft X-ray scattering, and grazing incidence wide angle X-ray scattering are used as an initial set of tools to determine the surface texture, the bulk compositional morphology, and the crystallization behavior, respectively. We find systematic variations and relate them to device performance. A solvent mixture of DCB/CF/DIO = 76:19:5 (v/v/v) yields a PCE of 6.71%.}, number={47}, journal={ADVANCED MATERIALS}, author={Ye, Long and Zhang, Shaoqing and Ma, Wei and Fan, Benhu and Guo, Xia and Huang, Ye and Ade, Harald and Hou, Jianhui}, year={2012}, month={Dec}, pages={6335–6341} }