The crystallinity of non-fullerene acceptors as the third component has an important role on nanomorphology optimization and charge transfer dynamics of ternary organic solar cells (OSCs). Herein, efficient ternary OSCs were fabricated by incorporating two typical non-fullerene acceptors with different crystallinity, (Z)-5-{[5-(15-{5-[(Z)-(3-Ethyl-4-oxo-2-thioxo-1,3-thiazolidin-5-ylidene)methyl]-8-thia-7.9-diazabicyclo [4.3.0] nona-1 (9),2,4,6-tetraen-2-yl}-9,9,18,18-tetrakis (2-ethylhexyl)-5.14-dithiapentacyclo [10.6.0.0^3,10.0^4,8.0^13,17]octadeca-1(12),2,4(8),6,10,13 (17),15-heptaen-6-yl)-8-thia-7.9-diazabicyclo [4.3.0]nona-1 (9),2,4,6-tetraen-2-yl]methylidene}-3-ethyl-2-thioxo-1,3-thiazolidin-4-one (EH-IDTBR) or (5Z, 5′Z)-5,5'-((7,7'-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b']dithiophene-2,7-diyl)bis (benzo [c][1,2,5]thiadiazole7,4diyl)) bis(methanylylidene))bis (3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR), into the host donor/acceptor active layers comprising of poly (3-hexythiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C71-butyric acid methylester (PC₇₁BM). As a result, the 21.5% and 22.7% increase of the power conversion efficiency (PCE) for the two ternary systems were achieved, respectively, which was attributed to the enhanced light harvesting capability, optimized bulk-heterojunction morphology and the formation of cascade energy level alignments that could introduce an additional pathway for efficient charge transfer. Although both the short-circuit current density (Jsc) and fill factor (FF) values were increased significantly by regulating the weight ratios of non-fullerene acceptors of two ternary systems, the O-IDTBR-based ternary OSCs showed the higher Jsc while P3HT:EH-IDTBR:PC₇₁BM system exhibited the higher FF values. The main difference of improved photovoltaic performance in the two ternary systems could be associated with the different blend morphology and charge carrier mobilities. In addition, nanomorphology studies suggested that lamellar stacking coherence lengths of P3HT in face-on orientation for EH-IDTBR- and O-IDTBR-based systems can be increased from 18.48 nm to 20.94 nm and 21.67 nm respectively, resulting from the stronger crystallinity of O-IDTBR than that of EH-IDTBR, which was beneficial for charge transport in the vertical direction. These results indicate that selecting the appropriate crystalline non-fullerene acceptors may be an effective strategy to optimize nanomorphology to further achieve high efficiency ternary OSCs.

作为第三个成分的非富勒烯受体的结晶度，对三元有机太阳能电池（OSC）的纳米形态优化和电荷转移动力学具有重要作用。在这里，有效的三元OSC通过结合两个典型的不同结晶度的非富勒烯受体，（Z）-5-{[5-（15- {5-[（Z）-（3-乙基-4-氧代-2） -thioxo-1,3-thiazolidin-5-yylne）methyl] -8-thia-7.9-diazabicyclo [4.3.0] nona-1（9），2,4,6-tetraen-2-yl} -9， 9,18,18-四（2-乙基己基）-5.14-二硫杂五环[10.6.0.0 ^3,10 .0 ^4,8 .0 ^13,17] octadeca-1（12），2,4（8），6,10,13（17），15-庚烯-6-基）-8-硫杂-7.9-二氮杂双环[4.3.0] nona-1（9 ），2,4,6-四烯-2-基]亚甲基} -3-乙基-2-硫代-1,3-噻唑烷丁-4-酮（EH-IDTBR）或（5Z，5'Z）-5， 5'-（（7,7'-（4,4,9,9-四辛基-4,9-二氢-s-indaceno [1,2-b：5,6-b']二噻吩-2,7-二（基）双（苯并[c] [1,2,5]噻二唑7,4二基））双（亚甲叉基））双（3-乙基-2-硫代噻唑并恶唑烷-4-酮）（O-IDTBR），进入宿主供体/受体活性层，由聚（3-己基噻吩-2,5-二基）（P3HT）和[6,6]-苯基-C71-丁酸甲酯（PC ₇₁BM）。结果，两个三元系统的功率转换效率（PCE）分别提高了21.5％和22.7％，这归因于增强的光收集能力，优化的体-异质结形态和级联能的形成能级对准可以为有效的电荷转移引入额外的途径。尽管通过调节两个三元体系的非富勒烯受体的重量比，短路电流密度（Jsc）和填充因子（FF）值均显着增加，但基于O-IDTBR的三元OSC显示出更高的Jsc，而P3HT ：EH-IDTBR：PC ₇₁BM系统表现出较高的FF值。两个三元体系中改善的光伏性能的主要区别可能与不同的共混物形态和电荷载流子迁移率有关。此外，纳米形态学研究表明，基于EH-IDTBR和O-IDTBR的系统，P3HT面对面取向的层状堆积相干长度可以分别从18.48 nm增加到20.94 nm和21.67 nm，这是由于C3的较强结晶性所致。 O-IDTBR比EH-IDTBR大，有利于垂直方向的电荷传输。这些结果表明，选择合适的晶体非富勒烯受体可能是优化纳米形态以进一步实现高效三元OSC的有效策略。