A fused tris(thienothiophene) (3TT) building block is designed and synthesized with strong electron‐donating and molecular packing properties, where three thienothiophene units are condensed with two cyclopentadienyl rings. Based on 3TT, a fused octacylic electron acceptor (FOIC) is designed and synthesized, using strong electron‐withdrawing 2‐(5/6‐fluoro‐3‐oxo‐2,3‐dihydro‐1H‐inden‐1‐ylidene)‐malononitrile as end groups. FOIC exhibits absorption in 600–950 nm region peaked at 836 nm with extinction coefficient of up to 2 × 10⁵m^–1 cm^–1, low bandgap of 1.32 eV, and high electron mobility of 1.2 × 10^–3 cm² V^–1 s^–1. Compared with its counterpart ITIC3 based on indacenothienothiophene core, FOIC exhibits significantly upshifted highest occupied molecular orbital level, slightly downshifted lowest unoccupied molecular orbital level, significantly redshifted absorption, and higher mobility. The as‐cast organic solar cells (OSCs) based on blends of PTB7‐Th donor and FOIC acceptor without additional treatments exhibit power conversion efficiencies (PCEs) as high as 12.0%, which is much higher than that of PTB7‐Th: ITIC3 (8.09%). The as‐cast semitransparent OSCs based on the same blends show PCEs of up to 10.3% with an average visible transmittance of 37.4%.

中文翻译：

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融合三（噻吩并噻吩）基电子受体，具有强大的近红外吸收性能，可用于高性能的铸态太阳能电池

设计并合成了具有强大的供电子和分子堆积特性的稠合三（噻吩并噻吩）（3TT）结构单元，其中三个噻吩并噻吩单元与两个环戊二烯基环稠合。基于3TT，使用强吸电子2‐（5 / 6‐氟‐3‐oxo‐2,3‐二氢‐1H‐茚满‐1―亚基）设计并合成了熔融八环电子受体（FOIC）‐丙二腈为端基。FOIC在600-950 nm处的吸收峰达到836 nm，消光系数高达2×10 ⁵ m ^–1 cm ^–1，低带隙为1.32 eV，高电子迁移率为1.2×10 ^–3 cm ² V ^{– 1}秒^–1。与基于吲哚并噻吩并噻吩核的同类物ITIC3相比，FOIC的最高占据分子轨道能级显着上移，最低的未占据分子轨道能级显着下移，吸收率显着红移，并且迁移率更高。基于PTB7-Th供体和FOIC受体的共混物而无需额外处理的铸态有机太阳能电池（OSC）的功率转换效率（PCE）高达12.0％，远高于PTB7-Th：ITIC3（ 8.09％）。基于相同共混物的铸态半透明OSC显示出PCE高达10.3％，平均可见光透射率为37.4％。