Proceedings of Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP24)
Publication date: 18th October 2023
Wide bandgap (WBG) Sn halide perovskite (Sn-HP) is an eco-friendly choice for tandem device technology. However, fast crystallization witnessed in Sn-HPs leads to inadequate film morphology and the substantial creation of defects, which compromise device performance. Here, the 4-Phenylthiosemicarbazide (4PTSC) precursor additive is selected to achieve a densely packed Sn-HP film with reduced imperfections. Chemical interaction between SnI2 and 4PTSC functional groups S=C-N (Sn···S=C-N), -NH2, and phenyl ring improved solution stability, assisting the retardation of perovskite crystallization through adduct formation, resulting in pinhole-free and compact morphology film. The 4PTSC passivates uncoordinated Sn2+ thus suppressing the formation of defects that lead to improved charge carrier lifetime. Besides, the hydrophobic nature of 4PTSC controls Sn2+ oxidation which inhibits moisture penetration and improves perovskite stability. A notable increase in open circuit voltage was observed from 0.78V (control) to 0.94V (4PTSC-1.0). The 4PTSC-1.0 device achieved 12.22% efficiency with negligible hysteresis. Furthermore, the unencapsulated 4PTSC-1.0 device retained outstanding device stability over 1200 h in ambient atmospheric conditions.