title: Solvents induced ZnO nanoparticles aggregation associated with their interfacial effect on organic solar cells.
abstract: ZnO nanofilm as a cathode buffer layer has surface defects due to the aggregations of ZnO nanoparticles, leading to poor device performance of organic solar cells. In this paper, we report the ZnO nanoparticles aggregations in solution can be controlled by adjusting the solvents ratios (chloroform vs methanol). These aggregations could influence the morphology of ZnO film. Therefore, compact and homogeneous ZnO film can be obtained to help achieve a preferable power conversion efficiency of 8.54% in inverted organic solar cells. This improvement is attributed to the decreased leakage current and the increased electron-collecting efficiency as well as the improved interface contact with the active layer. In addition, we find the enhanced maximum exciton generation rate and exciton dissociation probability lead to the improvement of device performance due to the preferable ZnO dispersion. Compared to other methods of ZnO nanofilm fabrication, it is the more convenient, moderate, and effective to get a preferable ZnO buffer layer for high-efficiency organic solar cells.
authors.affiliation: Institute of New Energy Technology, Ningbo Institute of Material Technology and Engineering (NIMTE), Chinese Academy of Science (CAS) , Ningbo, Zhejiang 315201, People's Republic of China.
authors.forename: Pandeng
authors.initials: P
authors.lastname: Li
authors.forename: Tonggang
authors.initials: T
authors.lastname: Jiu
authors.forename: Gang
authors.initials: G
authors.lastname: Tang
authors.forename: Guojie
authors.initials: G
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Li
authors.forename: Junfeng
authors.initials: J
authors.lastname: Fang
keywords: aggregations of ZnO nanoparticles; cathode buffer layer; inverted organic solar cells; mixed solvents