Highly Emissive Halide Perovskite Nanocrystals: From Lead to Lead-Free

Nanostructured halide perovskites have highly yielded record LEDs. This is mainly due to their higher versatility in the local management of charge carriers, which has enabled photoluminescence quantum yields (PLQYs) close to 100%. However, the most promising perovskite structures mainly rely on lead analogues, thereby hindering their commercial applications due to the toxicity of lead. Here, we summarized the recent developments of highly emissive perovskite nanocrystals (NCs) from lead to lead free. Given the performance and current challenges, possible future research directions of emissive halide perovskite nanocrystals are provided in this rapidly evolving field of more extensive basic research and practical applications.