碱金属碘化物后处理制备大晶粒CH3NH3PbI3钙钛矿薄膜

有机-无机杂化钙钛矿太阳电池作为一种低成本、高效的光伏技术具有巨大的发展潜力,制备大晶粒、致密的钙钛矿吸收层仍然是获得高效钙钛矿太阳电池的关键因素。本文采用简单碱金属碘化物(NaI,KI,CsI)后处理方法诱导CH3NH3PbI3薄膜二次结晶,成功制备了微米级大晶粒、致密的CH3NH3PbI3钙钛矿薄膜。与KI相比,NaI和CsI更有利于促进钙钛矿薄膜晶粒长大。并且碱金属碘化物后处理能够钝化晶界,降低钙钛矿薄膜内的缺陷。最后,碱金属掺杂对CH3NH3PbI3带隙的影响很小,不改变其接近单节电池带隙的最优值。因此,碱金属碘化物后处理是进一步提高钙钛矿太阳电池的有效方法。

Preparation of Large-grain CH3NH3PbI3 Perovskite Films by Alkali Metal Iodides Post-treatment Method

Organic-inorganic hybrid perovskite solar cells have shown great prospect as a low-cost and high efficiency photovoltaic technology.The fabrication of large-grain perovskite absorber layer with high surface coverage is still most critical to obtain high performance of perovskite solar cells.Here,the MAPbI 3 is recrystallized through a simple alkali metal iodides post-treatment method,andμm-sized grain MAPbI 3 with high surface coverage is obtained.NaI and CsI are more effective in promoting the crystallization of perovskite thin films than KI.And the grain boundaries of the perovskite can be passivated by the alkali metal iodides post-treatment,thus the defect states in film decrease.Finally,alkali metal iodides post-treatment adjusts the band gap of MAPbI 3,which close to the optimal band gap of the single-junction solar cell.So,this reported method provides a pathway for further improving the performance of perovskite solar cells.