Tailoring photophysical properties of low-dimensional CsPbBr3 nanocrystals via solvothermal morphology control

All-inorganic CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals with low-dimensional morphologies exhibit unique photophysical properties due to quantum confinement effects. However, systematic studies correlating their structure with photophysical performance have been hindered by the lack of effective synthesis strategy for controllably tailoring their morphologies. Herein, we address this challenge using a simple solvothermal method to synthesize CsPbBr₃ nanowires and nanoplates with controlled size and morphology by solely varying reaction time (30 min–24 h). Prolonged reaction time induces a size-dependent morphological transition from nanowires (∼2 nm diameter) to nanoplates (∼2–3 nm thickness), accompanied by a quantum confinement-mediated redshift in photoluminescence (PL) spectra. Fluorescence lifetime measurements and Urbach energy analysis reveal a reduction in defects within nanoplates compared to nanowires, effectively suppressing non-radiative recombination pathways. Temperature-dependent PL studies further demonstrate that CsPbBr₃ nanoplates exhibit a higher exciton binding energy (320.78 meV), indicating enhanced electron-hole interactions. These findings not only achieve precise morphology modulation but also establish a fundamental structure-property relationship, highlighting the critical role of defect engineering and quantum confinement in tailoring the photophysical performance of low-dimensional perovskite nanocrystals. This work provides a strategic framework for designing high-performance perovskite nanomaterials for advanced optoelectronic applications.