Exploring photoexcitation effects on Cs3Bi2Br9 perovskite single crystal properties

Abstract

Lead-free halide perovskite single crystals (SCs) offer a compelling alternative for optoelectronic devices due to their superior intrinsic properties. Despite advancements in excellent perovskite SCs, analyzing defects remains crucial. This two-fold approach can both enhance device performance and provide insights into the interactions between light-induced carriers and these defects within the material. This work investigates defects in Cs3Bi2Br9 perovskite SCs using photoexcitation. Photocurrent and photocapacitance measurements are employed to analyze these light-induced defects and their influence on the material's properties. The examination of Cs3Bi2Br9 SCs properties alongside a gold electrode involves evaluating both bulk and interfacial defect densities. This assessment is carried out by analyzing the capacitive behavior in response to different wavelengths λR, λG, and λB (λR = 652.54 nm, λG = 539.06 nm, and λB = 413.28 nm). The temporary reaction to light of individual crystals indicates the presence of carrier capture and subsequent recombination processes. The analysis of the response to light under different situations offers insights into potential defect origins within SCs of Cs3Bi2Br9. This extensive optoelectronic investigation unveils a critical connection between light illumination conditions, carrier transport properties, and overall system efficiency. A comprehensive comprehension of light-triggered defects in perovskites could aid in identifying the source of electrical inefficiency and in the creation of exceptionally effective optoelectronic systems.