Invited Paper TF+SS-ThA6
Materials Synthesis and Device Fabrication for Novel Inorganic Perovskites

Thursday, October 24, 2019, 4:00 pm, Room A122-123

In recent years, organic lead halide perovskite materials have attracted much attention due to their outstanding optoelectric properties and low manufacturing cost. To improve the stability of perovskite solar cells, inorganic CsPbI₃ perovskite has been demonstrated as promising material for solar cells owing to the superb photoelectronic property and composition stability. However, the low stability of perovskite phase CsPbI₃ (α-phase) with an appropriate band gap under ambient environment hinders its practical application.

Here, we investigate new ways of synthesizing inorganic perovskite materials and optimizing the device stability through dimensional engineering. we tailor the three-dimension CsPbI₃ perovskite into quasi-two-dimensional Cs_xPEA_1-xPbI₃ perovskite, where an optimal Cs_xPEA_1-xPbI₃ film remains stable in α phase up to 250℃. Moreover, we further present an in-depth investigation of the so-called stable ‘α-CsPbI₃,’ especially the starting material hydrogen lead trihalide (HPbI₃, also known as PbI₂∙xHI) that is usually used for synthesizing α-CsPbI₃. We notice that the “mythical” HPbI₃, the often-assumed reaction product of HI and PbI₂, does not actually exist. Instead, adding acid to DMF is known to generate a weak base dimethylamine (DMA) through hydrolysis, and with the presence of PbI₂ the actual final product is believed to be a compound of DMAPbI₃. Our findings offer new insights into producing inorganic perovskite materials, and lead to further understanding in perovskite materials for solar cells with improved efficiency and stability.