Defect Suppression and Charge Transport in PbSe-Decorated CsPbBr₃ Nanocrystal Transistors

Lead halide perovskites are promising semiconductors for optoelectronic and transistor applications, yet their performance is often limited by surface and interface defects that trap charge carriers. In this work, we investigate charge transport in PbSe-decorated CsPbBr_₃ nanocrystal-based thin-film transistors (TFTs). Atom probe tomography provides direct three-dimensional nanoscale evidence of PbSe incorporation within individual CsPbBr_₃ nanocrystals, confirming uniform integration. Kelvin probe force microscopy reveals Fermi-level modulation and improved hole injection, while low-temperature photoluminescence spectra show a redshift from 521 to 532 nm with enhanced intensity, indicative of exciton confinement and interfacial coupling. Temperature-dependent transport exhibits two conduction regimes: three-dimensional Mott variable-range hopping below 140 K and nearest-neighbour hopping between 150-300 K. These findings demonstrate that controlled PbSe incorporation effectively tunes interfacial energetics and charge transport, advancing perovskite-based transistor performance.