Systematic side-chain engineering on nonacyclic acceptor–donor–acceptor (A–D–A) nonfullerene acceptors, NNFA[n, m], was carried out. “n” and “m” stand for the number of alkyl carbon atoms in the in-plane and out-of-plane side chains, respectively. Five acceptors, NNFA[0, 6], NNFA[6, 3], NNFA[6, 6], NNFA[12, 3] and NNFA[12, 6], were prepared and applied in organic solar cells by blending with a wide-bandgap copolymer donor (FTAZ). The alkyl chains substantially affect the NNFAs’ solubility and photovoltaic performance. The solubility varies from 23 mg mL⁻¹ to 226 mg mL⁻¹ in chloroform when changing the total alkyl carbons (2n + 4m). If the total alkyl carbons are equal, the NNFA with longer out-of-plane alkyl chains (higher “m”) shows higher solubility than that with longer in-plane alkyl chains (higher “n”). NNFA[6, 6] and NNFA[12, 3] with medium solubility (∼100 mg mL⁻¹) present suitable miscibility with FTAZ, and afford more favorable morphology and higher device performance than other NNFAs. FTAZ:NNFA[12, 3] solar cells gave the highest power conversion efficiency of 10.81%.

中文翻译：

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了解对A–D–A受体的侧链影响：平面内和平面外†

对非无环受体-供体-受体（A–D–A）富勒烯受体，NNFA [ n，m ]进行了系统的侧链工程。“ n ”和“ m ”分别代表平面内和平面外侧链中的烷基碳原子数。制备了五种受体，分别为NNFA [0，6]，NNFA [6，3]，NNFA [6，6]，NNFA [12，3]和NNFA [12，6]，并将其与有机太阳能电池混合使用宽带隙共聚物供体（FTAZ）。烷基链基本上影响NNFA的溶解度和光伏性能。从23毫克毫升的溶解度而变化^-1至226毫克毫升^-1的氯仿改变总烷基碳时（2 Ñ + 4米）。如果总烷基碳原子相等，则具有较长平面外烷基链（较高的“ m ”）的NNFA的溶解度要高于具有较长平面内烷基链（较高的“ n ”）的溶解度。中等溶解度（〜100 mg mL ^-1）的NNFA [6，6]和NNFA [12，3]具有与FTAZ的适当混溶性，并且比其他NNFA具有更好的形态和更高的器件性能。FTAZ：NNFA [12，3]太阳能电池的功率转换效率最高，为10.81％。