Morphology Optimization via Side Chain Engineering Enables All-Polymer Solar Cells with Excellent Fill Factor and Stability

• DOI: 10.1021/jacs.8b05038
• Publication Date: 2018-06-26T17:37:50Z
• Authors: Xi Liu; Chaohong Zhang; Chunhui Duan; Mengmeng Li; Zhicheng Hu; Jing Wang; Feng Liu; Ning Li; Christoph J. Brabec; René A. J. Janssen; Guillermo C. Bazan; Fei Huang; Yong Cao
• Keywords: Side chain; Acceptor; Thermal Stability

All-polymer solar cells (all-PSCs) composed of conjugated polymers as both donor and acceptor components in bulk heterojunction photoactive layers have attracted increasing attention. However, it is a big challenge to achieve optimal morphology polymer:polymer blends. In response, we report herein new strategy adjust the nanoscale organization for all-PSCs. Specifically, side chain engineering well-known naphthalene diimide (NDI)-based polymer N2200 modulated by introducing fraction linear oligoethylene oxide (OE) chains replace branched alkyl on NDI units synthesizing series NDI-based acceptors NOEx, where x percentage OE substituted relative total units. Compared reference NOE0, OE-chain-containing NOE10 offers much higher power conversion efficiency (PCE) 8.1% with record high fill factor (FF) 0.75 Moreover, NOE10-based all-PSC exhibits excellent long-term thermal stabilities >97% initial PCE being maintained after 300 h aging at 65 °C. This work demonstrates an effective optimization highly efficient stable all-PSCs shows potential alternative commercially available N2200.