Rational Design and Controlled Synthesis of Perovskite Nanocrystals for Bridging Dimensionality and Excited-State Dynamics

Abstract Cesium lead bromide perovskites exhibit morphology-dependent emission that can be harnessed to design high-performance optoelectronic devices. This work establishes how thermodynamic and kinetic factors govern the formation of CsPbBr3 quantum dots, nanosheets, and nanowires and correlates dimensionality with carrier dynamics and band alignment using temperature-dependent photoluminescence (TDPL), cyclic voltammetry (CV), and transient absorption spectroscopy (TAS) and photodetector device performance. Quantum confinement and ligand-driven surface passivation are used to tune emission properties (e.g., wavelength and linewidth) and to boost radiative efficiency. Smaller quantum dots display stronger excitonic character with reduced exciton–phonon coupling and enhanced exciton binding energy, whereas higher-dimensional nanostructures show an unusual photoluminescence lifetime shortening above 260 K. Furthermore, the I–V and I–T measurements for the photodetector device indicate that the nanosheets exhibit a strong photoresponse across all three dimensionalities. Transient absorption spectroscopy reveals that lower dimensionality suppresses Auger recombination, identifying nanostructure design as a powerful lever for controlling nonradiative losses in perovskite emitters and enabling the rational design of next-generation optoelectronic devices.