Abstract：
All-inorganic CsPbI3 perovskite has emerged as an important photovoltaic material due to its high thermal stability and suitable bandgap for tandem devices. Currently, the cell performance of CsPbI3 solar cells is mainly subject to a large open-circuit voltage (VOC ) deficit. Herein, a multifunctional room-temperature molten salt, dimethylamine acetate (DMAAc) is demonstrated, which not only directly acts as a solvent for precursor solutions, but also regulates the phase conversion process of the CsPbI3 film for high-efficiency photovoltaics. DMAAc can stabilize the DMAPbI3 structure and eliminate the Cs4 PbI6 intermediate phase, which is easily spatially segregated. Meanwhile, a new homogeneous intermediate phase DMAPb(I,Ac)3 is formed, which finally affords high-quality CsPbI3 films. With this approach, the charge capture activity of defects in the CsPbI3 film is significantly suppressed. Consequently, a VOC of 1.25 V and >21% power conversion efficiency are achieved, which is the record highest reported thus far. This intermediate phase-regulation strategy is believed to be applicable to other perovskite material systems.
摘要：
全无机CsPbI3钙钛矿由于其高热稳定性和适合串联器件的带隙而成为重要的光伏材料。目前,CsPbI3太阳能电池的电池性能主要受到大的开路电压(VOC)亏空的影响。在这里，一种多功能的室温熔盐,证明了乙酸二甲胺（DMAAc），它不仅直接充当前体溶液的溶剂，而且还调节了用于高效光伏的CsPbI3薄膜的相转换过程。DMAAc可以稳定DMAPbI3结构，消除Cs4PbI6中间相，很容易在空间上隔离。同时,一种新的均匀中间相DMAPb(I，Ac)3已形成,最终提供高质量的CsPbI3薄膜。通过这种方法，CsPbI3膜中缺陷的电荷捕获活性被显著抑制。因此,实现了1.25V的VOC和>21%的功率转换效率，这是迄今为止报道的最高记录。这种中间相位调节策略被认为适用于其他钙钛矿材料系统。
