Decomposition of Organometal Halide Perovskite Films on Zinc Oxide Nanoparticles

• DOI: 10.1021/acsami.5b04695
• Publication Date: 2015-08-17T16:41:41Z
• Authors: Yuanhang Cheng; Qing-Dan Yang; Jingyang Xiao; Qifan Xue; Ho-Wa Li; Zhiqiang Guan; Hin-Lap Yip; Sai-Wing Tsang
• Keywords: Zinc hydroxide

Solution processed zinc oxide (ZnO) nanoparticles (NPs) with excellent electron transport properties and a low-temperature process is viable candidate to replace titanium dioxide (TiO2) as layer develop high-efficiency perovskite solar cells on flexible substrates. However, the number of reported high-performance using ZnO-NPs still limited. Here we report detailed investigation chemistry crystal growth CH3NH3PbI3 ZnO-NP thin films. We find that films would severely decompose into PbI2 upon thermal annealing bare surface. X-ray photoelectron spectroscopy (XPS) results show hydroxide groups surface accelerate decomposition To reduce decomposition, introduce buffer in between layers. commonly used small molecule [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) can slow down but cannot completely avoid decomposition. On other hand, polymeric poly(ethylenimine) (PEI) effectively separate perovskite, which allows larger formation annealing. The power conversion efficiencies photovoltaic are significantly increased from 6.4% 10.2% by replacing PC61BM PEI layer.