To investigate the effect of substitution of cyano groups (CN) on D-π-A type conjugated copolymer in photophysical and photovoltaic properties, a non-CN-substituted P4TIH and a CN-substituted P4TIN isoindigo-based copolymers were synthesized and characterized. Having dicyano-substituted bithiophene as electron-donating segment and isoindigo as electron-accepting segment, P4TIN exhibits a deeper highest occupied molecular orbital energy level (HOMO) than that of the non-CN-substituted P4TIH. Benefiting from the improved solubility via copolymer side-chain substituent (2-decylteradecyl), inverted solar cells fabricated with a thick (∼200 nm) active layer (P4TIN:PC₆₁BM, 1:2.0) have achieved a very high open circuit voltage of 1.06 V. High power conversion efficiency of 8.36% can be reached without thermal annealing treatment or processing solvent additives.

中文翻译：

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用于高性能聚合物-富勒烯太阳能电池的异靛蓝-二氰基二噻吩基共聚物达到 1.06 V 开路电压和 8.36% 功率转换效率

为研究氰基(CN)取代对D-π-A型共轭共聚物光物理和光伏性能的影响，合成并表征了一种非CN-取代的P4TIH和一种CN-取代的P4TIN异靛蓝共聚物。P4TIN 具有双氰基取代的二噻吩作为给电子链段和异靛蓝作为电子接受链段，与非 CN 取代的P4TIH相比， P4TIN表现出更深的最高占据分子轨道能级 (HOMO) 。受益于通过共聚物侧链取代基（2-癸基十四烷基）提高溶解度，用厚（~200 nm）有源层（P4TIN：PC _{61 ）制造的倒置太阳能电池}BM, 1:2.0) 实现了 1.06 V 的非常高的开路电压。无需热退火处理或加工溶剂添加剂即可达到 8.36% 的高功率转换效率。