Post-synthesis Treatment with Lead Bromide for Obtaining Near-Unity Photoluminescence Quantum Yield and Ultra-stable Amine-Free CsPbBr<sub>3</sub> Perovskite Nanocrystals
Syed Akhil, V. G. Vasavi Dutt, Rahul Singh, Nimai Mishra
Abstract
Improving the photoluminescence quantum yields (PLQYs) and optimizing the stability have been challenging tasks to promote cesium lead halide (CsPbX3; X = Cl, Br, and I) perovskite nanocrystals (PNCs) for real optoelectronic applications. In recent years, the amine-free synthesis route has become an option for making stable CsPbX3 PNCs. Further improvement in the PLQY and stability of amine-free PNCs is paramount for their practical applications. Herein, we have introduced a simple lead bromide (PbBr2) post-treatment process to achieve the near-unity PLQY (>95%) in amine-free CsPbBr3 PNCs. Furthermore, PbBr2 treatment enables these materials to have a drastically improved stability under different environmental conditions (polar solvents, light, and heat). In addition, a green-emitting down-converted light-emitting diode was fabricated using PbBr2-treated amine-free CsPbBr3 PNCs, which shows its considerable prospects for display applications. Thus, our results will promote these PbBr2-treated amine-free inorganic perovskite nanocrystals for commercial development in optoelectronic applications.