Tunable Optoelectronic Properties of CsPbBr3 Perovskite Nanocrystals for Photodetectors Applications

Inorganic halide perovskite nanocrystals (NCs) have drawnconsiderableattention in recent years due to their improved stability, superiorphotophysical properties, and defect-tolerant nature, which allowsfor high carrier mobility and efficient charge transport in variousoptoelectronic devices. The bandgap and size of halide perovskitenanocrystals can be tuned through a variety of approaches, includingcation/anion exchange, ligand modification, and precursor concentrationadjustment. In this article, we investigate the effects of precursorconcentration on the structural, optical, and electronic propertiesof cesium lead bromide (CsPbBr3) nanocrystals. We havesynthesized & SIM;13-50 nm nanocrystals from four differentconcentrations of precursor solutions. It has been observed that theexcitonic absorption band increases with particle size as the precursorconcentration decreases. The steady state photoluminescence intensitydecreases due to a shorter carrier lifetime (in solution). We havefabricated photodetectors using four different-size samples and showthat the photoresponsivity increases with increasing particle size.The nanocrystals synthesized from the diluted precursor solution (0.005M) exhibits the highest detectivity of 2.84 x 10(9) jonesdue to their larger crystal size and fewer defect states, which resultsin a higher carrier diffusion length with reduced free carrier recombination.

Automated summary

Inorganic halide perovskite nanocrystals have gained significant attention due to their enhanced stability, superior photophysical properties, and defect-tolerant nature. This study investigates the effects of precursor concentration on the structural, optical, and electronic properties of cesium lead bromide nanocrystals. It is found that as the precursor concentration decreases, the excitonic absorption band increases and the steady state photoluminescence intensity decreases. Photodetectors fabricated using different-size samples show that the photoresponsivity increases with increasing particle size. The nanocrystals synthesized from the diluted precursor solution exhibit the highest detectivity due to their larger crystal size and fewer defect states.