Dual-function of the ZnO nano-sheets as light absorber scaffold and electron transport material in perovskite solar cells

Recent advances in the development of perovskite solar cells using CH3NH3PbI3 as the absorber material have reached over 18.7% in power conversion efficiency. The best performance perovskite-based cells required support of a mesoporous charge collector. In this work we present a new process for preparing perovskite solar cells with the structure of AZO/Au/AZO(AAA)/ZnO-sheets/CH3NH3PbI3/HTM/Au. Herein, ZnO nanosheets layer was prepared by electrochemical deposition method using zinc nitrate hexahydrate as nutrient solution, then annealed at 150 degrees C in ambient air. The results show that high crystal ZnO sheets assembled simply from AZO top layer could act as electron transporter and scaffold for perovskite layer. The presentation of ZnO scaffold was exploited to improve 19% in power conversion efficiency, offering great promise for further improvement of the low-temperature, low-cost processing solar technology.