The role of additives on the performance of CsPbI3-based perovskite solar cells (PSCs) is investigated. As additives, HCl, HBr, HI, NH4I, NH4Cl, and NH4Br were used. One of the major disadvantages in the widely used methylammonium-based perovskite material is its hygroscopic nature, which is a self-contained property of the methylammonium ion. The NH3 group of methylammonium is hydrogen bonded to H2O, which is a water molecule. Since the bonding force is more stable than the CH3NH3-PbI3 hydrogen bond, H2O is attracted to bond, resulting in collapse of the crystal structure. As a result, the overall stability of the device is decreased. So, inorganic PSC, CsPbI3, was chosen in this experiment. Because CsPbI3 needs high annealing temperature(>300°C), we added HCl, HBr, HI, NH4I, NH4Cl, and NH4Br as additives and investigated the effect of them. It is expected that the additives increase the solubility of low materials, reducing the process temperature. The CsPbI3 layer was synthesized by one-step coating of CsI mixed with PbI2 and a additives in N,N-dimethylformamide respectively. We investigated the power conversion efficiency of PSCs depend on the annealing temperature and additive content. In this presentation, we will discuss the effect of additives.
This research was supported in part by National Research Foundation of Korea (NRF) grants provided by the Korean government (MSIP) (Nos 2015K1A3A1A59073839, 2017H1D8A1030599, 2017K1A3A1A67014432) and in part by Korea Agency for Infrastructure Technology Advancement grant funded by Ministry of Land, Infrastructure and Transport (17IFIP-B133622-01).