基于多元稠环受电子单元的聚合物给体的设计合成与光伏性能研究

有机太阳能电池作为新一代有前景的光伏技术，因其质轻、柔性和半透明等独特优势受到广泛关注。近年来，得益于高性能非富勒烯受体材料的发展，有机太阳能电池的光伏性能不断获得新的突破。在受体材料迅速发展的背景下，给体材料的研究进展相对有些滞后。广泛使用的给体材料是由给电子和受电子单元交替共聚得到的D-A型聚合物给体。在聚合物给体的发展中，苯并[1,2-b:4,5-b']二噻吩（BDT）已经成为最重要的给电子单元，受电子单元的精细调控往往起着关键作用。因此，设计和开发新型受电子单元对推进聚合物给体的发展具有重要意义。本论文设计并合成了一系列多元稠环受电子单元及其聚合物给体，并应用于非富勒烯有机太阳能电池中，系统研究了结构调控对光伏性能的影响。主要研究内容如下：

通过噻吩共轭拓展策略实现了含氯化噻吩侧链的四元稠环二噻吩并喹喔啉受电子单元的构建及其聚合物主链构象优化。聚合物给体PBDQx-Cl、PBDQx-TCl和PBDQx-2TCl被设计合成。PBDQx-TCl中喹喔啉的稠环化实现了比PBDQx-Cl更宽的带隙和更低的HOMO能级，促进了与BTP-eC9的匹配性。基于PBDQx-TCl的器件获得了11.36%的良好效率，远高于基于PBDQx-Cl的器件性能（7.36%）。主链构象的优化促使PBDQx-2TCl比PBDQx-TCl获得更好的平面性和聚集性质，形成良好的纤维网络状活性层形貌。基于PBDQx-2TCl的器件获得了更高16.17%的效率。

将上述稠环二噻吩并喹喔啉的噻吩侧链更换为苯环，可以构建得到更平面的五元稠环二噻吩并吩嗪（DTP）受电子单元。采用氯介导策略，三种氯化程度不同的聚合物给体PBDP-H、PBDP-Cl和PBDP-2Cl被设计合成。研究表明，逐步引入氯原子有效降低了给体HOMO能级并且实现了对活性层微观形貌的精细调控。最终，基于PBDP-2Cl:BTIC-BO-4Cl器件获得了开路电压、短路电流密度和填充因子的全面提升，实现最高13.34%的效率，远高于基于PBDP-Cl（9.84%）和PBDP-H（6.66%）的器件。

采取异构化和引入杂原子的协同设计策略，在上述DTP结构基础上，设计得到由苯并吡嗪（BP）、苯并噻二唑（BT）和苯并硒二唑（BS）分别与苯并[2,1-b:3,4-b']二噻吩（BDP）结合的五元稠环二噻吩并萘并芳杂环受电子单元（BDP-BP、BDP-BT和BDP-BS）及其对应的聚合物给体PBDP-BP、PBDP-BT和PBDP-BS，并系统地研究了这三种聚合物给体的光伏性能。与Y6匹配，基于PBDP-BT的活性层薄膜表现出最强的吸收、均匀形貌和较强的结晶度，从而获得了最高15.14%的效率。基于PBDP-BP和PBDP-BS器件分别获得了8.55%和6.85%的效率。

在上述BDP-BT单元结构上进一步融合了另一个苯并噻二唑单元，构建了具有更大共轭平面的六元稠环双噻吩并萘并双噻二唑（BDP-DBT）受电子单元。基于BDP-DBT单元，两种含有不同数量噻吩桥的氯化聚合物给体PBDBT-Cl和PBDBT-TCl被设计合成。两种聚合物给体均展现出宽的带隙和强的聚集能力。结合准平面异质结（Q-PHJ）器件，基于PBDBT-TCl/BTP-eC9器件获得了最高16.68%的效率以及良好的储藏稳定性（T₈₈ = 3195 h）、光稳定性（T₈₀ = 911 h）和热稳定性（T₈₀ = 164 h）。

本论文系统地构建了四元、五元和六元稠环受电子单元及其聚合物给体，探索了它们在非富勒烯有机太阳能电池中的应用潜力和结构性能关系。希望这些研究将会为未来高效稳定的聚合物给体的开发提供有益的指导。

[1] ZHANG G C, LIN F R, QI F, et al. Renewed prospects for organic photovoltaics[J]. Chemical Reviews, 2022, 122: 14180-14274.
[2] YAO H F, HOU J H. Recent advances in single-junction organic solar cells[J]. Angewandte Chemie International Edition, 2022, 61: 202209021.
[3] FU J H, YANG Q G, HUANG P H, et al. Rational molecular and device design enables organic solar cells approaching 20% efficiency[J]. Nature Communications, 2024, 15: 1830.
[4] LI Y W, XU G Y, CUI C H, et al. Flexible and semitransparent organic solar cells[J]. Advanced Energy Materials, 2017, 8: 1701791.
[5] WANG W X, CUI Y, ZHANG T, et al. High-performance organic photovoltaic cells under indoor lighting enabled by suppressing energetic disorders[J]. Joule, 2023, 7: 1067-1079.
[6] DAI S X, ZHAN X W. Nonfullerene acceptors for semitransparent organic solar cells[J]. Advanced Energy Materials, 2018, 8: 1800002.
[7] KEARNS D, CALVIN M. Photovoltaic effect and photoconductivity in laminated organic systems[J]. The Journal of Chemical Physics, 1958, 29: 950-951.
[8] TANG C W. Two-layer organic photovoltaic cell[J]. Applied Physics Letters, 1986, 48: 183-185.
[9] SARICIFTCI N S, BRAUN D, ZHANG C, et al. Semiconducting polymer-buckminsterfullerene heterojunctions: diodes, photodiodes, and photovoltaic cells[J]. Applied Physics Letters, 1993, 62: 585-587.
[10] YU G, GAO J, HUMMELEN J C, et al. Polymer photovoltaic cells: enhanced efficiencies via a network of internal donor-acceptor heterojunctions[J]. Science, 1995, 270: 1789-1791.
[11] DANG M T, HIRSCH L, WANTZ G, et al. Controlling the morphology and performance of bulk heterojunctions in solar cells. lessons learned from the benchmark poly(3-hexylthiophene):
[6,6]-phenyl-C61-butyric acid methyl ester system[J]. Chemical Reviews, 2013, 113: 3734-3765.
[12] QIAN D P, YE L, ZHANG M J, et al. Design, application, and morphology study of a new photovoltaic polymer with strong aggregation in solution state[J]. Macromolecules, 2012, 45: 9611-9617.
[13] LIU Y H, ZHAO J B, LI Z K, et al. Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells[J]. Nature Communications, 2014, 5: 5293.
[14] YE L, ZHANG S Q, HUO L J, et al. Molecular design toward highly efficient photovoltaic polymers based on two-dimensional conjugated benzodithio- phene[J]. Accounts of Chemical Research, 2014, 47: 1595-1603.
[15] YAO H F, YE L, ZHANG H, et al. Molecular design of benzodithiophene-based organic photovoltaic materials[J]. Chemical Reviews, 2016, 116: 7397-7457.
[16] HU H W, CHOW P C Y, ZHANG G Y, et al. Design of donor polymers with strong temperature-dependent aggregation property for efficient organic photovoltaics[J]. Accounts of Chemical Research, 2017, 50: 2519-2528.
[17] ZHANG M J, GUO X, MA W, et al. A large-bandgap conjugated polymer for versatile photovoltaic applications with high performance[J]. Advanced Materials, 2015, 27: 4655-4660.
[18] JIN Y C, CHEN Z M, XIAO M J, et al. Thick film polymer solar cells based on naphtho
[1,2-c:5,6-c]bis
[1,2,5]thiadiazole conjugated polymers with efficiency over 11%[J]. Advanced Energy Materials, 2017, 7: 1700944.
[19] NIELSEN C B, HOLLIDAY S, CHEN H Y, et al. Non-fullerene electron acceptors for use in organic solar cells[J]. Accounts of Chemical Research, 2015, 48: 2803-2812.
[20] WADSWORTH A, MOSER M, MARKS A, et al. Critical review of the molecular design progress in non-fullerene electron acceptors towards commercially viable organic solar cells[J]. Chemical Society Reviews, 2019, 48: 1596-1625.
[21] LIN Y Z, WANG J Y, ZHANG Z G, et al. An electron acceptor challenging fullerenes for efficient polymer solar cells[J]. Advanced Materials, 2015, 27: 1170-1174.
[22] SINGH S P, SUMAN. Impact of end group on the performance of non-fullerene acceptors for organic solar cell applications[J]. Journal of Materials Chemistry A, 2019, 7: 22701-22729.
[23] YUAN J, ZHANG Y Q, ZHOU L Y, et al. Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core[J]. Joule, 2019, 3: 1140-1151.
[24] LI S X, LI C Z, SHI M M, et al. New phase for organic solar cell research: emergence of Y-series electron acceptors and their perspectives[J]. ACS Energy Letters, 2020, 5: 1554-1567.
[25] MEREDITH P, LI W, ARMIN A. Nonfullerene acceptors: a renaissance in organic photovoltaics?[J]. Advanced Energy Materials, 2020, 10: 2001788.
[26] WEI Q Y, LIU W, LECLERC M, et al. A-D-A′-D-A non-fullerene acceptors for high-performance organic solar cells[J]. Science China Chemistry, 2020, 63: 1352-1366.
[27] LIU W, XU X, YUAN J, et al. Low-bandgap non-fullerene acceptors enabling high-performance organic solar cells[J]. ACS Energy Letters, 2021, 6: 598-608.
[28] LUO Z H, XU T L, ZHANG C E, et al. Side-chain engineering of nonfullerene small-molecule acceptors for organic solar cells[J]. Energy & Environmental Science, 2023, 6: 2732-2758.
[29] LIANG S J, LIU B Q, KARUTHEDATH S, et al. Double-cable conjugated polymers with pendent near-infrared electron acceptors for single-component organic solar cells[J]. Angewandte Chemie International Edition, 2022, 134: 202209316.
[30] LIANG S J, XIAO C Y, XIE C C, et al. 13% single-component organic solar cells based on double-cable conjugated polymers with pendent Y-series acceptors[J]. Advanced Materials, 2023, 35: 2300629.
[31] CHEN H, ZHAO T X, LI L, et al. 17.6%-efficient quasiplanar heterojunction organic solar cells from a chlorinated 3D network acceptor[J]. Advanced Materials, 2021, 33: 2102778.
[32] LI X R, DU X Y, ZHAO J W, et al. Layer-by-layer solution processing method for organic solar cells[J]. Solar RRL, 2021, 5: 2000592.
[33] LIU C H, FU Y W, ZHOU J P, et al. Alkoxythiophene directed fibrillization of polymer donor for efficient organic solar cells[J]. Advanced Materials, 2023: 2308608.
[34] XU X P, YU L Y, MENG H F, et al. Polymer solar cells with 18.74% efficiency: from bulk heterojunction to interdigitated bulk heterojunction[J]. Advanced Functional Materials, 2021, 32: 2108797.
[35] WANG L, CHEN C, FU Y W, et al. Donor-acceptor mutually diluted heterojunctions for layer-by-layer fabrication of high-performance organic solar cells[J]. Nature Energy, 2024, 9: 208-218.
[36] XIAO M J, MENG Y D, TANG L T, et al. Solid additive-assisted selective optimization strategy for sequential deposited active layers to construct 19.16% efficiency binary organic solar cells[J]. Advanced Functional Materials, 2023: 2311216.
[37] CAO C C, WANG H T, QIU D S, et al. Quasiplanar heterojunction all-polymer solar cells: a dual approach to stability[J]. Advanced Functional Materials, 2022, 32: 2201828.
[38] WANG H T, CAO C C, CHEN H, et al. Oligomeric acceptor: a “two-in-one” strategy to bridge small molecules and polymers for stable solar devices[J]. Angewandte Chemie International Edition, 2022, 61: 202201844.
[39] ZHANG G P, ZHAO C Y, ZHU L X, et al. Toluene processed all-polymer solar cells with 18% efficiency and enhanced stability enabled by solid additive: comparison between sequential-processing and blend-casting[J]. Energy & Environmental Materials, 2023: 12683.
[40] ZHAO Z M, ZHAO J J, CHUNG S, et al. Suppressing bimolecular charge recombination and energetic disorder with planar heterojunction active layer enables 18.1% efficiency binary organic solar cells[J]. ACS Materials Letters, 2023, 5: 1718-1726.
[41] WU Z H, SUN C, DONG S, et al. N-type water/alcohol-soluble naphthalene diimide-based conjugated polymers for high-performance polymer solar cells[J]. Journal of the American Chemical Society, 2016, 138: 2004-2013.
[42] CHENG P, WANG J Y, ZHAN X W, et al. Constructing high-performance organic photovoltaics via emerging non-fullerene acceptors and tandem-junction structure[J]. Advanced Energy Materials, 2020, 10: 2000746.
[43] ZHENG Z, WANG J Q, BI P Q, et al. Tandem organic solar cell with 20.2% efficiency[J]. Joule, 2021, 6: 171-184.
[44] STOLTZFUS D M, DONAGHEY J E, ARMIN A, et al. Charge generation pathways in organic solar cells: assessing the contribution from the electron acceptor[J]. Chemical Reviews, 2016, 116: 12920-12955.
[45] CHENG P, LI G, ZHAN X W, et al. Next-generation organic photovoltaics based on non-fullerene acceptors[J]. Nature Photonics, 2018, 12: 131-142.
[46] LU L Y, ZHENG T Y, WU Q H, et al. Recent advances in bulk heterojunction polymer solar cells[J]. Chemical Reviews, 2015, 115: 12666-12731.
[47] HAVINGA E E, TEN H W, WYNBERG H. A new class of small band gap organic polymer conductors[J]. Polymer Bulletin, 1992, 29: 119-126.
[48] DUAN C H, HUANG F, CAO Y. Recent development of push-pull conjugated polymers for bulk-heterojunction photovoltaics: rational design and fine tailoring of molecular structures[J]. Journal of Materials Chemistry, 2012, 22: 10416-10434.
[49] WUDL F, KOBAYASHI M, HEEGER A J. Poly(isothianaphthene)[J]. The Journal of Organic Chemistry, 1984, 49: 3382-3384.
[50] RONCALI J. Molecular engineering of the band gap of π-conjugated systems: facing technological applications[J]. Macromolecular Rapid Communications, 2007, 28: 1761-1775.
[51] BREDAS J-L, NORTON J E, CORNIL J, et al. Molecular understanding of organic solar cells: the challenges[J]. Accounts of Chemical Research, 2009, 42: 1691-1699.
[52] KOßMEHL G, BEIMLING P, MANECKE G. Über polyarylenalkenylene und polyheteroarylenalkenylene, 14. synthesen und charakterisierung von poly- (thieno
[2′,3′:1,2]benzo
[4,5-b]thiophen-2,6-diylvinylenarylenvinylen)en, poly (4,8-dimethoxythieno
[2′,3′:1,2]benzo
[4,5-b]thiophen-2,6-diylvinylenarylenv- inylen)en und einigen modellverbindungen[J]. Die Makromolekulare Chemie, 1983, 184: 627-650.
[53] PAN H L, LI Y N, WU Y L, et al. Low-temperature, solution-processed, high-mobility polymer semiconductors for thin-film transistors[J]. Journal of the American Chemical Society, 2007, 129: 4112-4113.
[54] HOU J H, PARK M H, ZHANG S Q, et al. Bandgap and molecular energy level control of conjugated polymer photovoltaic materials based on benzo
[1, 2-b:4,5-b′]dithiophene[J]. Macromolecules, 2008, 41: 6012-6018.
[55] LIANG Y Y, FENG D Q, WU Y, et al. Highly efficient solar cell polymers developed via fine-tuning of structural and electronic properties[J]. Journal of the American Chemical Society, 2009, 131: 7792-7799.
[56] HUO L J, HOU J H, ZHANG S Q, et al. A polybenzo
[1,2-b:4,5-b′]dithiophene derivative with deep homo level and its application in high-performance polymer solar cells[J]. Angewandte Chemie International Edition, 2010, 49: 1500-1503.
[57] HUO L J, ZHANG S Q, GUO X, et al. Replacing alkoxy groups with alkylthienyl groups: a feasible approach to improve the properties of photovoltaic polymers[J]. Angewandte Chemie International Edition, 2011, 50: 9697-9702.
[58] LAIO S H, JHUO H J, CHENG Y S, et al. Fullerene derivative-doped zinc oxide nanofilm as the cathode of inverted polymer solar cells with low-bandgap polymer (PTB7-Th) for high performance[J]. Advanced Materials, 2013, 25: 4766-4771.
[59] CUI C H, WONG W Y, LI Y F. Improvement of open-circuit voltage and photovoltaic properties of 2D-conjugated polymers by alkylthio substitution[J]. Energy & Environmental Science, 2014, 7: 2276-2284.
[60] ZHANG M J, GUO X, ZHANG S Q, et al. Synergistic effect of fluorination on molecular energy level modulation in highly efficient photovoltaic polymers[J]. Advanced Materials, 2014, 26: 1118-1123.
[61] DU Z K, BAO X C, LI Y H, et al. Balancing high open circuit voltage over 1.0 V and high short circuit current in benzodithiophene-based polymer solar cells with low energy loss: a synergistic effect of fluorination and alkylthiolation[J]. Advanced Energy Materials, 2017: 1701471.
[62] XUE L W, YANG Y K, XU J Q, et al. Side chain engineering on medium bandgap copolymers to suppress triplet formation for high-efficiency polymer solar cells[J]. Advanced Materials, 2017, 29: 1703344.
[63] ZHAO Q Q, QU J F, HE F. Chlorination: an effective strategy for high-performance organic solar cells[J]. Advanced Science, 2020, 7: 2000509.
[64] YAO H F, WANG J W, XU Y, et al. Recent progress in chlorinated organic photovoltaic materials[J]. Accounts of Chemical Research, 2020, 53: 822-832.
[65] ZHANG S Q, QIN Y P, ZHU J, et al. Over 14% efficiency in polymer solar cells enabled by a chlorinated polymer donor[J]. Advanced Materials, 2018, 30: 1800868.
[66] CAHO P J, MU Z, WANG H, et al. Chlorination of side chains: a strategy for achieving a high open circuit voltage over 1.0 V in benzo
[1,2-b:4,5-b′]di- thiophene-based non-fullerene solar cells[J]. ACS Applied Energy Materials, 2018, 1: 2365-2372.
[67] CHAO P J, CHEN H, ZHU Y L, et al. Chlorination of conjugated side chains to enhance intermolecular interactions for elevated solar conversion[J]. Macromolecules, 2019, 53: 165-173.
[68] CHAO P J, LIU L Z, ZHOU J D, et al. Multichloro-substitution strategy: facing low photon energy loss in nonfullerene solar cells[J]. ACS Applied Energy Materials, 2018, 1: 6549-6559.
[69] HINSBERG O. Ueber chinoxaline[J]. Berichte der Deutschen Chemischen Gesellschaft, 1884, 17: 318-323.
[70] YUAN J, QIU L X, ZHANG Z G, et al. A simple strategy to the side chain functionalization on the quinoxaline unit for efficient polymer solar cells[J]. Chemical Communications, 2016, 52: 6881-6884.
[71] YUAN J, QIU L X, ZHANG Z G, et al. Tetrafluoroquinoxaline based polymers for non-fullerene polymer solar cells with efficiency over 9%[J]. Nano Energy, 2016, 30: 312-320.
[72] XU S T, FENG L L, YUAN J, et al. Hexafluoroquinoxaline based polymer for nonfullerene solar cells reaching 9.4% efficiency[J]. ACS Applied Materials & Interfaces, 2017, 9: 18816-18825.
[73] WANG T, LAU T K, LU X H, et al. A medium bandgap D-A copolymer based on 4-alkyl-3,5-difluorophenyl substituted quinoxaline unit for high performance solar cells[J]. Macromolecules, 2018, 51: 2838-2846.
[74] XU S T, WANG X J, FENG L L, et al. Optimizing the conjugated side chains of quinoxaline based polymers for nonfullerene solar cells with 10.5% efficiency[J]. Journal of Materials Chemistry A, 2018, 6: 3074-3083.
[75] YUAN J, LIU Y, ZHU C, et al. Asymmetric quinoxaline-based polymer for high efficiency non-fullerene solar cells[J]. Acta Physico-Chimica Sinica, 2018, 34: 1272-1278.
[76] SUN C K, ZHU C, MENG L, et al. Quinoxaline-based D-A copolymers for the applications as polymer donor and hole transport material in polymer/perovskite solar cells[J]. Advanced Materials, 2021, 34: 2104161.
[77] SUN C K, PAN F, QIU B B, et al. D-A copolymer donor based on bithienyl benzodithiophene D-unit and monoalkoxy bifluoroquinoxaline A-unit for high performance polymer solar cells[J]. Chemistry of Materials, 2020, 32: 3254-3261.
[78] ZHU C, MENG L, ZHANG J Y, et al. A quinoxaline-based D-A copolymer donor achieving 17.62% efficiency of organic solar cells[J]. Advanced Materials, 2021, 33: 2100474.
[79] ZENG L, MA R J, ZHANG Q, et al. Synergy strategy to the flexible alkyl and chloride side-chain engineered quinoxaline-based D-A conjugated polymers for efficient non-fullerene polymer solar cells[J]. Materials Chemistry Frontiers, 2021, 5: 1906-1916.
[80] ZHANG Q, SONG X, SINGH R, et al. Chloride side-chain engineered quinoxaline-based D-A copolymer enabling non-fullerene organic solar cells with over 16% efficiency[J]. Chemical Engineering Journal, 2022, 437: 135182.
[81] YU T, XU X P, ZHANG G J, et al. Wide bandgap copolymers based on quinoxalino
[6,5-f].quinoxaline for highly efficient nonfullerene polymer solar cells[J]. Advanced Functional Materials, 2017, 27: 1701491.
[82] ZHANG Y J, ZHOU P C, WANG J C, et al. Designing a thiophene-fused quinoxaline unit to build D-A copolymers for non-fullerene organic solar cells[J]. Dyes and Pigments, 2020, 174: 108022.
[83] XU Y, CUI Y, YAO H F, et al. A new conjugated polymer that enables the integration of photovoltaic and light-emitting functions in one device[J]. Advanced Materials, 2021, 33: 2101090.
[84] CUI Y, XU Y, YAO H F, et al. Single-junction organic photovoltaic cell with 19% efficiency[J]. Advanced Materials, 2021, 33: 2102420.
[85] ZHAO T X, CAO C C, WANG H T, et al. Highly efficient all-polymer solar cells from a dithieno
[3,2-f:2′,3′-h]quinoxaline-based wide band gap donor[J]. Macromolecules, 2021, 54: 11468-11477.
[86] KE C X, LAI X, WANG H T, et al. Subtle effect of alkyl substituted π-bridges on dibenzo[a,c]phenazine based polymer donors towards enhanced photovoltaic performance[J]. Chinese Journal of POLYMER SCIENCE, 2022, 40: 889-897.
[87] BEI Q, ZHANG B, WANG K F, et al. Benzothiadiazole-based materials for organic solar cells[J]. Chinese Chemical Letters, 2023, 35: 108438.
[88] DHANABALAN A, VAN DUREN J K J, VAN HAL P A, et al. Synthesis and characterization of a low bandgap conjugated polymer for bulk heterojunction photovoltaic cells[J]. Advanced Functional Materials, 2001, 11: 255-262.
[89] ZHOU H X, YANG L Q, STUART A C, et al. Development of fluorinated benzothiadiazole as a structural unit for a polymer solar cell of 7 % effi- ciency[J]. Angewandte Chemie International Edition, 2011, 50: 2995-2998.
[90] WANG N, CHEN Z, WEI W, et al. Fluorinated benzothiadiazole-based conjugated polymers for high-performance polymer solar cells without any processing additives or post-treatments[J]. Journal of the American Chemical Society, 2013, 135: 17060-17068.
[91] FENG K, YANG G F, XU X P, et al. High-performance wide bandgap copolymers using an edot modified benzodithiophene donor block with 10.11% efficiency[J]. Advanced Energy Materials, 2017, 8: 1602773.
[92] ZHANG G J, XU X P, BI Z Z, et al. Fluorinated and alkylthiolated polymeric donors enable both efficient fullerene and nonfullerene polymer solar cells[J]. Advanced Functional Materials, 2018, 28: 1706404.
[93] CHAO P J, JOHNER N, ZHONG X W, et al. Chlorination strategy on polymer donors toward efficient solar conversions[J]. Journal of Energy Chemistry, 2019, 39: 208-216.
[94] HU Z M, CHEN H, QU J F, et al. Design and synthesis of chlorinated benzothiadiazole-based polymers for efficient solar energy conversion[J]. ACS Energy Letters, 2017, 2: 753-758.
[95] MO D Z, WANG H, CHEN H, et al. Chlorination of low-band-gap polymers: toward high-performance polymer solar cells[J]. Chemistry of Materials, 2017, 29: 2819-2830.
[96] DONG Y Y, YANG H, WU Y, et al. Towards improved efficiency of polymer solar cells via chlorination of a benzo
[1,2-b:4,5-b′]dithiophene based polymer donor[J]. Journal of Materials Chemistry A, 2019, 7: 2261-2267.
[97] WANG M, HU X W, LIU P, et al. Donor-acceptor conjugated polymer based on naphtho
[1,2-c:5,6-c]bis
[1,2,5]thiadiazole for high-performance polymer solar cells[J]. Journal of the American Chemical Society, 2011, 133: 9638-9641.
[98] WANG L X, CAI D D, ZHENG Q D, et al. Low band gap polymers incorporating a dicarboxylic imide-derived acceptor moiety for efficient polymer solar cells[J]. ACS Macro Letters, 2013, 2: 605-608.
[99] LIU Q S, JIANG Y F, JIN K, et al. 18% efficiency organic solar cells[J]. Science Bulletin, 2020, 65: 272-275.
[100] QIN J Q, ZHANG L X, ZUO C T, et al. A chlorinated copolymer donor demonstrates a 18.13% power conversion efficiency[J]. Journal of Semiconductors, 2020, 42: 010501.
[101] ZHAO T X, WANG H, PU M R, et al. Tuning the molecular weight of chlorine-substituted polymer donors for small energy loss[J]. Chinese Journal of Chemistry, 2021, 39: 1651-1658.
[102] TANG H L, NING J H, WANG K, et al. Dithienobenzoselenadiazole-based polymer donors with tuned side chains for efficient polymer solar cells[J]. ACS Applied Energy Materials, 2023, 6: 4079-4088.
[103] THOMPSON B C, FRECHET J M. Polymer-fullerene composite solar cells[J]. Angewandte Chemie International Edition, 2008, 47: 58-77.
[104] LIU Y H, LIU B W, MA C Q, et al. Recent progress in organic solar cells (part i material science)[J]. Science China Chemistry, 2022, 65: 224-268.
[105] LI S S, YE L, ZHAO W C, et al. Energy-level modulation of small-molecule electron acceptors to achieve over 12% efficiency in polymer solar cells[J]. Advanced Materials, 2016, 28: 9423-9429.
[106] ZHAO W C, LI S S, YAO H F, et al. Molecular optimization enables over 13% efficiency in organic solar cells[J]. Journal of the American Chemical Society, 2017, 139: 7148-7151.
[107] ZHANG H, YAO H F, HOU J X, et al. Over 14% efficiency in organic solar cells enabled by chlorinated nonfullerene small-molecule acceptors[J]. Advanced Materials, 2018, 30: 1800613.
[108] ZHAO F W, DAI S X, WU Y, et al. Single-junction binary-blend nonfullerene polymer solar cells with 12.1% efficiency[J]. Advanced Materials, 2017, 29: 1700144.
[109] YAO H F, WANG J W, XU Y, et al. Terminal groups of nonfullerene acceptors: design and application[J]. Chemistry of Materials, 2023, 35: 807-821.
[110] CUI Y, YAO H F, ZHANG J Q, et al. Over 16% efficiency organic photovoltaic cells enabled by a chlorinated acceptor with increased open-circuit voltages[J]. Nature Communications, 2019, 10: 2515.
[111] CUI Y, YAO H F, ZHANG J Q, et al. Single-junction organic photovoltaic cells with approaching 18% efficiency[J]. Advanced Materials, 2020, 32: 1908205.
[112] LI C, ZHOU J D, SONG J L, et al. Non-fullerene acceptors with branched side chains and improved molecular packing to exceed 18% efficiency in organic solar cells[J]. Nature Energy, 2021, 6: 605-613.
[113] ZHU L, ZHANG M, XU J Q, et al. Single-junction organic solar cells with over 19% efficiency enabled by a refined double-fibril network morphology[J]. Nature Materials, 2022, 21: 656-663.
[114] YU H, QI Z Y, ZHANG J Q, et al. Tailoring non-fullerene acceptors by selenium-incorporated heterocycles for organic solar cells with over 16% efficiency[J]. Journal of Materials Chemistry A, 2020, 8: 23756-23765.
[115] WANG J L, YANG C, AN Q S, et al. Synergistic strategy of manipulating the number of selenophene units and asymmetric central core of small molecular acceptors enables polymer solar cells with 17.5% efficiency[J]. Angewandte Chemie International Edition, 2021, 60: 19241.
[116] SHI J Y, CHEN Z Y, LIU H, et al. Selenium-substitution asymmetric acceptor enables efficient binary organic solar cells over 18.3% via regulating molecular stacking and phase separation[J]. Advanced Energy Materials, 2023, 13: 2301292.
[117] FAN B B, LIN F, WU X, et al. Selenium-containing organic photovoltaic materials[J]. Accounts of Chemical Research, 2021, 54: 3906-3916.
[118] QU J F, CHEN H, ZHOU J D, et al. Chlorine atom-induced molecular interlocked network in a non-fullerene acceptor[J]. ACS Applied Materials & Interfaces, 2018, 10: 39992-40000.
[119] LAI H J, CHEN H, ZHOU J D, et al. Isomer-free: precise positioning of chlorine-induced interpenetrating charge transfer for elevated solar conversion[J]. iScience, 2019, 17: 302-314.
[120] LAI H J, ZHAO Q Q, CHEN Z Y, et al. Trifluoromethylation enables a 3D interpenetrated low-band-gap acceptor for efficient organic solar cells[J]. Joule, 2020, 4: 688-700.
[121] LAI H J, HE F. Crystal engineering in organic photovoltaic acceptors: a 3D network approach[J]. Advanced Energy Materials, 2020, 10: 2002678.
[122] MA L J, ZHANG S Q, HOU J H. Crystal structures in state-of-the-art non-fullerene electron acceptors[J]. Journal of Materials Chemistry A, 2022, 11: 481-494.
[123] XU J Q, LIN F, ZHU L, et al. The crystalline behavior and device function of nonfullerene acceptors in organic solar cells[J]. Advanced Energy Materials, 2022, 12: 2201338.
[124] LIU J, CHEN S S, QIAN D P, et al. Fast charge separation in a non-fullerene organic solar cell with a small driving force[J]. Nature Energy, 2016, 1: 16089.
[125] QIAN D P, ZHENG Z L, YAO H F, et al. Design rules for minimizing voltage losses in high-efficiency organic solar cells[J]. Nature Materials, 2018, 17: 703-709.
[126] ZHANG G Y, NING H J, CHEN H, et al. Naphthalenothiophene imide-based polymer exhibiting over 17% efficiency[J]. Joule, 2021, 5: 931-944.
[127] QIU D D, SHI Y N, LI Y, et al. Conjugation expansion strategy enables highly stable all-polymer solar cells[J]. Chinese Chemical Letters, 2023, 34: 108019.
[128] SHEN X Y, LAI X, LAI H J, et al. Isomerism strategy to optimize aggregation and morphology for superior polymer solar cells[J]. Macromolecules, 2022, 55: 6384-6393.
[129] JAEWON L, SIN D H, CLEMENT J A, et al. Medium-bandgap conjugated polymers containing fused dithienobenzochalcogenadiazoles: chalcogen atom effects on organic photovoltaics[J]. Macromolecules, 2016, 49: 9358-9370.
[130] MATEKER W R, MCGEHEE M D. Progress in understanding degradation mechanisms and improving stability in organic photovoltaics[J]. Advanced Materials, 2017, 29: 1603940.
[131] ZHU L, ZHANG M, ZHONG W K, et al. Progress and prospects of the morphology of non-fullerene acceptor based high-efficiency organic solar cells[J]. Energy & Environmental Science, 2021, 14: 4341-4357.
[132] LAI X, LAI H J, DU M Z, et al. Bilayer quasiplanar heterojunction organic solar cells with a co-acceptor: a synergistic approach for stability and efficiency[J]. Chemistry of Materials, 2022, 34: 7886-7896.