气相辅助电沉积法低温制备CH_3NH_3PbI_3钙钛矿薄膜的研究

Preparation of Perovskite CH_3NH_3PbI_3 Thin Films By Vapor-Assisted Electro-deposition at Low Temperature

采用低成本的气相辅助电沉积方法(vapor-assisted electro-deposition,VAED)成功制备了面积为15 cm^2均匀致密的钙钛矿薄膜。首先通过电化学沉积制备PbO_2薄膜,然后与HI气体反应得到PbI_2薄膜,接下来再与HI和CH3NH2混合气体反应,得到CH_3NH_3PbI_3薄膜。实验发现:电化学沉积电压对PbO_2薄膜的表面形貌和微结构有重要影响;在PbO_2向PbI_2的转化过程中,随着反应时间的减小,PbI_2的结晶性逐渐增强,最佳反应时间为10 min;在钙钛矿的转化过程中,当HI/CH_3NH_2体积比为1∶2时可获得均匀致密、四方相的钙钛矿薄膜。本研究提供了一种低温制备大面积均匀CH_3NH_3PbI_3薄膜的方法,得到的CH_3NH_3PbI_3薄膜可望在光电器件中得到应用。

A uniformly dense perovskite film with an area of 15 cm2 was successfully prepared by low-cost vapor-assisted electro-deposition （VAED）. Firstly, PbO2 film was prepared by electro-deposition and then reacted with HI gas to obtain PbI2 film, and then reacted with HI and CH3NH2 mixed gas to obtain CH3NH3PbI3 film. The experimental results show that the electro-deposition voltage had an important influence on the surface morphology and mierostructure of PbO2 films. During the conversion of PbO2 to PbI2, the crystallinity of PbI2 gradually increased with the decrease of reaction time, and the optimum reaction time was 10 rain ; In the process of perovskite conversion, a uniform and compact perovskite film with cube phase can be obtained when the volume ratio of HI/CH3 NH2 was 1 ： 2. This study provided a preparation method of large-area CH3NH3PbI3 films in a low-temperature way, and the obtained CH3NH3PbI3 thin films was expected to be used in optoelectronic devices.