| 초록 |
One of the major disadvantages in the widely used methylammonium (CH3NH3)-based perovskite material is its hygroscopicity, which is a self-contained property of the CH3NH3+. The NH3 group of CH3NH3 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, perovskite solar cells (PSCs) used formamidinium cesium lead triiodide (FACsPbI3) was chosen in this experiment. In this study, Pb(SCN)2, NH4SCN and NaSCN were added as an additive to improve the power conversion efficiency (PCE) of FACsPbI3 PSCs. J-V curve, X-ray diffraction, field emission scanning electron microscope, and UV-vis were measured to confirm the effect of thiocyanate ion on FACsPbI3. Especially, NH4SCN helps to enhance performance of PSCs. The PCE of PSCs with NH4SCN increased from 3.75% to 8.29%. The PCE of 6.98% and 6.79% were obtained for Pb(SCN)2 and NaSCN, respectively. It seemed that SCN- is partly substituted for I-, resulting in a FACsPb(SCN)3I3-x perovskite. From results, thiocyanate ion is expected to be useful for fabricating FACsPbI3 PSCs with high efficiency. Acknowledgment This research was supported in part by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2017K1A3A1A67014432) and in part by the Basic Research Laboratory of the NRF funded by the Korean government (2018R1A4A1022647). |
