Morphology optimization via side chain engineering enables all-polymer solar cells with excellent fill factor and stability

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

Research output: Contribution to journalArticleAcademicpeer-review

128 Citations (Scopus)
141 Downloads (Pure)

Abstract

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

Original languageEnglish
Pages (from-to)8934-8943
Number of pages10
JournalJournal of the American Chemical Society
Volume140
Issue number28
DOIs
Publication statusPublished - 18 Jul 2018

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