Interface-enhanced organic solar cells with extrapolated T80 lifetimes of over 20 years

Xiang Xu, Jingyang Xiao, Guichuan Zhang, Long Wei, Xuechen Jiao, Hin Lap Yip, Yong Cao

Research output: Contribution to journalArticleResearchpeer-review

56 Citations (Scopus)

Abstract

With recent advances in the power conversion efficiency (PCE) of organic solar cells (OSCs) based on novel donor and non-fullerene acceptor (NFAs), improving the stability of these systems has become the most important issue for their practical applications. Herein, an efficient and highly stable OSC, containing a novel polymer donor and a non-fullerene acceptor system, is reported. The OSC is based on an inverted device structure that utilizes a self-assembled fullerene monolayer (C60-SAM) as the cathode modification layer, and an efficient and highly stable OSC composes of a polymer donor of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-alt-3-fluorothie-no[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and a non-fullerene acceptor of (2,2′-((2Z,2′Z)-(((4,4,9,9-Tetrakis(4-hexylphenyl)-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(4-((2ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene −2,1-diylidene))dimalononitrile) (IEICO-4F) is presented, showing a PCE of 10%. It further achieves an extrapolated T80 lifetime (the time required to reach 80% of initial performance) of 34,000 h, operating under one sun illumination equivalent. Based on an estimated solar irradiance of 1500 kWh/(m2 year) for China, a potential lifetime of 22 years is inferred for the OSC. Further investigation reveals that the reported C60-SAM modification stabilizes the OSC active layer morphology by lowering the surface energy of the underlying ZnO electron transport layer and suppressing trap-assisted recombination, thereby improving photostability. The results of this work establish important guidelines for the development of non-fullerene based OSCs with enhanced stability and pave the way for the commercialization of OSC technology.

Original languageEnglish
Pages (from-to)208-216
Number of pages9
JournalScience Bulletin
Volume65
Issue number3
DOIs
Publication statusPublished - 15 Feb 2020

Keywords

  • Green solvent
  • Interlayer modification
  • Non-fullerene acceptor
  • Organic solar cell
  • Photostability

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