Effect of particle size and halide composition on structural and optical properties of CsPbX₃nanocrystals

Cesium lead halide perovskite nanocrystals (NCs) are emerging as a promising material for next-generation optoelectronic systems. This work investigates how variations in particle size and halide composition affect the structural and optical properties of CsPbX₃NCs. CsPbBr₃NCs of different sizes were prepared using a hot-injection procedure, with the ability to regulate the quenching time, and it was found that larger NCs have a smaller band gap. The crystal structure was found to be cubic. The influence of the halide composition was analyzed by synthesizing CsPbCl₃, CsPbBr₃, and CsPbI₃under the same conditions. CsPbCl₃showed the broadest bandgap and shortest lifetime, CsPbI₃the closest bandgap and longest lifetime, and CsPbBr₃showed a good compromise between bandgap, luminescence intensity, and structural stability. Optical tuning was also confirmed with respect to size and composition, with reference to UV-visible absorption and photoluminescence tests; blue, green, and red emissions were observed in the case of CsPbCl₃, CsPbBr₃, and CsPbI₃, respectively, with UV illumination. These findings demonstrate the synergistic nature of particle size and halide composition in designing the structural and optical characteristics of CsPbX₃NCs to offer principles of perovskite-based devices.