title: Performance enhancement of fullerene-based solar cells by light processing.
abstract: A key challenge to the commercialization of organic bulk heterojunction solar cells is the achievement of morphological stability, particularly under thermal stress conditions. Here we show that a low-level light exposure processing step during fabrication of blend polymer:PC60BM solar cells can result in a 10-fold increase in device thermal stability and, under certain conditions, enhanced device performance. The enhanced stability is linked to the light-induced oligomerization of PC60BM that effectively hinders their diffusion and crystallization in the blend. We thus suggest that light processing may be a promising, general and cost-effective strategy to optimize fullerene-based solar cell performance. The low level of light exposure required suggests not only that this may be an easily implementable strategy to enhance performance, but also that light-induced PC60BM oligomerization may have inadvertently influenced previous studies of organic solar cell device behaviour.
authors.affiliation: Centre for Plastic Electronics and Department of Chemistry, Imperial College London, London SW7 2AZ, UK.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.forename: Him Cheng
authors.initials: HC
authors.lastname: Wong
authors.forename: Zhenggang
authors.initials: Z
authors.lastname: Huang
authors.forename: Hongliang
authors.initials: H
authors.lastname: Zhong
authors.forename: Ching Hong
authors.initials: CH
authors.lastname: Tan
authors.forename: Wing Chung
authors.initials: WC
authors.lastname: Tsoi
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Kim
authors.forename: James R
authors.initials: JR
authors.lastname: Durrant
authors.forename: João T
authors.initials: JT
authors.lastname: Cabral
mesh_terms: D003460:Crystallization; D037741:Fullerenes / Q000737:chemistry*; D006801:Humans; D008027:Light; D058105:Polymerization; D012993:Solar Energy / Q000706:statistics & numerical data*; D013830:Thiadiazoles / Q000737:chemistry*
chemical_list: D037741:Fullerenes; D013830:Thiadiazoles