Sun Po, Li Xiangzhi, Wang Yulong, Shan Haiquan, Xu Jiaju, Liu Changmei, Zhang Cong, Chen Fei, Xu Zongxiang, Chen Zhi-Kuan, Huang Wei
Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), National Jiangsu Synergistic Innovation Center for Advanced Materials, Nanjing Tech University 30 South Puzhu Road Nanjing 211816 China
Department of Chemistry, South University of Science and Technology of China Shenzhen P. R. China
RSC Adv. 2018 Jul 12;8(44):25031-25039. doi: 10.1039/c8ra03792b. eCollection 2018 Jul 9.
Three small molecules SBF-1DPPDCV, SBF-2DPPDCV and SBF-4DPPDCV consisting of a spirobifluorene (SBF) unit as the core and one, two, and four diketopyrrolopyrrole dicyanovinyl (DPPDCV) units as the arms have been designed and synthesized for solution-processed bulk-heterojunction (BHJ) solar cells. The UV-Vis absorption and cyclic voltammetry measurement of these compounds showed that all these compounds have an intense absorption band over 300-750 nm with a LUMO energy level at around -3.87 eV. When pairing with PTB7-Th as the donor, devices fabricated based on PTB7-Th : SBF-4DPPDCV blends showed a decent PCE of 3.85%, which is the highest power conversion efficiency (PCE) amongst the three DPP acceptor fabricated devices without extra treatment. Devices with SBF-1DPPDCV and SBF-2DPPDCV acceptors showed lower PCEs of 0.26% for SBF-1DPPDCV and 0.98% for SBF-2DPPDCV respectively. The three dimensional (3D) structure of SBF-4DPPDCV facilitates the formation of a 3D charge-transport network and thus enables a rational electron-transport ability (1.04 × 10 cm V s), which further leads to a higher (10.71 mA cm). These findings suggest that multi-arm acceptors present better performance than one-arm or two-arm molecules for organic solar cells.
已设计并合成了三种小分子SBF-1DPPDCV、SBF-2DPPDCV和SBF-4DPPDCV，它们以螺二芴（SBF）单元为核心，分别以一个、两个和四个二酮吡咯并吡咯二氰基乙烯（DPPDCV）单元为臂，用于溶液处理的体异质结（BHJ）太阳能电池。这些化合物的紫外-可见吸收和循环伏安测量表明，所有这些化合物在300-750nm范围内都有一个强吸收带，最低未占分子轨道（LUMO）能级约为-3.87eV。当与作为给体的PTB7-Th配对时，基于PTB7-Th : SBF-4DPPDCV共混物制备的器件显示出3.85%的良好功率转换效率（PCE），这是三种DPP受体制备的器件在未经额外处理情况下的最高功率转换效率。含有SBF-1DPPDCV和SBF-2DPPDCV受体的器件分别显示出较低的PCE，SBF-1DPPDCV为0.26%，SBF-2DPPDCV为0.98%。SBF-4DPPDCV的三维（3D）结构有助于形成3D电荷传输网络，从而具有合理的电子传输能力（1.04×10 cm V s），进而导致更高的电流密度（10.71 mA cm）。这些发现表明，对于有机太阳能电池，多臂受体比单臂或双臂分子表现出更好的性能。
