CsSnBr3 and Cs3Bi2Br9: Structural, Optical Characteristics, and Application in a Schottky Barrier Diode

The search for alternatives to Pb‐based perovskites, due to concerns about stability and toxicity, has led to the exploration of Pb‐free options. Tin (Sn) and bismuth (Bi) are promising candidates, given their similar ionic radii to Pb and the isoelectronic nature of Pb2+ and Bi3+, which suggest comparable chemical properties. Among these, CsSnBr3 and Cs3Bi2Br9 are relatively underexplored but offer lower toxicity and enhanced stability while demonstrating optoelectronic properties suitable for various applications. In this study, CsSnBr3 and Cs3Bi2Br9 nanocrystals are synthesized using a colloidal method and integrated into Schottky diodes. X‐ray photoelectron spectroscopy analysis of the surface chemistry confirms improved thermal and phase stability compared to Pb‐based perovskites. Schottky diode parameters, including ideality factor, barrier height, and series resistance are assessed using conventional thermionic emission, modified Cheung's, and Norde's models. The Cs3Bi2Br9‐based Schottky diode exhibits superior electrical performance with the lowest series resistance and optimal barrier height. Electrical impedance spectroscopy results indicated that CsSnBr3 has higher resistances and lower capacitances than Cs3Bi2Br9, reflecting lower charge carrier mobility and more defects, although the R1C1 regions in both materials demonstrated faster charge dynamics, making them ideal for high‐speed applications. Cs3Bi2Br9 perovskite nanocrystals excel as Schottky diodes, surpassing CsSnBr3 perovskite nanocrystals in junction properties. This superiority arises from their narrow size distribution, minimal oxidation, and enhanced stability.