Quest of Ideal Precursors for RT Synthesis of Luminescent CsPbBr ₃ Perovskite QDs for LED Phosphor Applications

Cesium lead bromide (CsPbBr₃) perovskite quantum dots (QDs) present a fascinating nanoscale material that has gained substantial attention in the field of optoelectronics and nanotechnology. Here in, we report the synthesis of CsPbBr₃ QDs using a modified ligand-assisted rapid precipitation (LARP) technique under ambient conditions and studied the impact of various cesium precursors on structural, morphological, and photophysical properties of as-synthesized QDs. It is observed that QDs obtained from CsOH exhibited the highest intensity-averaged lifetime (τI ≈ 50 ns) and photoluminescence quantum yield (46%). This is the first report for the synthesis of the CsPbBr₃ QDs employing CsOH, and astonishingly, the QDs obtained from this precursor showed superior stability and photoluminescence owing to better passivation of surface trap states. The photostability of CsPbBr₃ QDs under blue LED excitation has been evaluated, which revealed that QDs synthesized from cesium hydroxide retained the highest luminescence during down-conversion, proving its applicability as QDs phosphor. The green emission intensity decreases by only ∼ 50% after 16 h of continuous operation, establishing the durability of the fluorophore film. Even after 6 months, the half-life emission intensity is 12 h. These observations advocated the impact of precursor choice on both quantum yield and long-term stability for illumination applications.