采用含二甲基亚砜(DMSO)添加剂的二步溶液法制备高质量CH3NH3PbI3吸收层, 并制备了结构为FTO/TiO2致密层/TiO2介孔层/CH3NH3PbI3吸收层/碳电极的碳基无空穴传输层的钙钛矿太阳能电池(PSCs)。研究了PbI2薄膜分别在相同浓度的MAI/IPA溶液中浸泡不同时间, 以及在不同浓度的MAI/IPA溶液中浸泡相同时间对CH3NH3PbI3薄膜的形貌、结构以及对PSCs光伏性能的影响规律。结果表明, 在PbI2/DMF溶液中添加DMSO之后使制备的PbI2薄膜呈多孔疏松状态, 有利于MAI/IPA溶液渗入PbI2薄膜内部, 缩短PbI2完全转换成CH3NH3PbI3的时间; 当浸泡时间为40 min时, 电池的光伏性能最佳, 其开路电压为0.82 V, 短路电流密度为21.21 mA/cm2, 填充因子为0.49, 光电转化效率为8.61%。但是当浸泡时间过长, CH3NH3PbI3薄膜表面会出现大晶粒, 导致电池的光伏性能变差。而在相同的浸泡时间下, MAI/IPA溶液的浓度则会显著影响PbI2转化成CH3NH3PbI3的速度, MAI/IPA溶液的浓度越高, PbI2完全转化成CH3NH3PbI3的速度越快。

In this paper, a two-step solution method including dimethyl sulfoxide(DMSO) as additive is used to prepare a high-quality CH3NH3PbI3 absorb layer for carbon-based hole conductor-free perovskite solar cells(PSCs), which have the structure consisting of FTO glass/compact TiO2/mesoporous TiO2/CH3NH3PbI3/carbon electrodes. The effects of dipping time and dipping concentration on the photovoltaic performance of PSCs are studied. Introducing some DMSO in the PbI2/DMF solutions results in formation of porous and loose PbI2 films, which shortens the time required for the complete conversion of PbI2 to perovskite. When the dipping time is 40 min, the PSCs have the best photovoltaic performance with the open circuit voltage of 0.82 V, the short-circuit current density of 21.21 mA/cm2, the fill factor of 0.49, and the photoelectric conversion efficiency of 8.61%. However, when the dipping time is too long, the large grains will appear on the surface of the CH3NH3PbI3 absorb layer, resulting in the poor photovoltaic performance of PSCs. In addition, the concentration of MAI/IPA solution will significantly affect the rate of the conversion of PbI2 to CH3NH3PbI3. The higher the concentration of MAI/IPA solution is, the faster the rate of the conversion of PbI2 to CH3NH3PbI3 is.