Diketopyrrolopyrrole-based acceptors with multi-arms for organic solar cells

Po Sun; Xiangzhi Li; Yulong Wang; Haiquan Shan; Jiaju Xu; Changmei Liu; Cong Zhang; Fei Chen; Zongxiang Xu; Zhi-Kuan Chen; Wei Huang

doi:10.1039/c8ra03792b

Diketopyrrolopyrrole-based acceptors with multi-arms for organic solar cells

RSC Adv. 2018 Jul 12;8(44):25031-25039. doi: 10.1039/c8ra03792b. eCollection 2018 Jul 9.

Authors

Po Sun^{1

2

3}, Xiangzhi Li^{1

2}, Yulong Wang², Haiquan Shan², Jiaju Xu², Changmei Liu¹, Cong Zhang¹, Fei Chen¹, Zongxiang Xu², Zhi-Kuan Chen¹, Wei Huang¹

Affiliations

¹ 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 iamzkchen@njtech.edu.cn iamwhuang@njtech.edu.cn.
² Department of Chemistry, South University of Science and Technology of China Shenzhen P. R. China xu.zx@sustc.edu.cn.
³ Analysis and Testing Central Facility, Engineering Research Institute, Anhui University of Technology Maanshan 243002 P. R. China sunpoo@ahut.edu.cn.

Abstract

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^-4 cm² V^-1 s^-1), which further leads to a higher J _sc (10.71 mA cm^-2). These findings suggest that multi-arm acceptors present better performance than one-arm or two-arm molecules for organic solar cells.