Near-Unity PLQY in Lead-Free Halide Perovskites and Perovskite-Inspired Halides for Light-Emitting Diode Applications

Lead-free halide perovskites (LFHPs) and perovskite-inspired halides have attracted considerable interest owing to their eco-friendly nature and distinctive optoelectronic properties, which make them suitable candidates for electroluminescent and phosphor materials in optoelectronic applications. Their tunable optical properties, photoluminescence quantum yields (PLQYs), and low environmental impacts make them viable substitutes for Pb-based perovskites. However, achieving near-unity PLQY is critical to enhance their efficiency and stability for practical applications. This review focuses on the emission mechanisms of LFHPs and perovskite-inspired halides, the factors influencing their luminescence, and emphasizes strategies to improve their PLQY. Techniques such as dimension reduction, surface passivation, doping, alloying, and crystal engineering are discussed, highlighting their roles in enhancing radiative recombination, mitigating nonradiative losses, and improving structural stability. Finally, the potential applications of LFHPs and perovskite-inspired halides as electroluminescent and phosphor materials in light-emitting diodes are explored, along with future research directions for their integration into next-generation optoelectronic technologies.