Optically pumped white light-emitting diodes based on metal halide perovskites and perovskite-related materials

Optically pumped white light-emitting diodes (WLEDs), consisting of blue/ultraviolet LED chips and down conversion phosphors, have a wide range of applications in our daily life, such as full color display and solid-state lighting. While remarkable progress in light quality, device efficiency, and lifetime has been achieved during the last two decades, many challenges remain in optically pumped WLEDs, and searching for low cost high performance down conversion phosphors is still of great interest. Recently, metal halide perovskites have emerged as a highly promising new generation of light emitters for their exceptional optical properties with high quantum efficiencies and color tunability, which have also inspired researchers to investigate their derivatives. In this perspective, we briefly review the progress during the last few years in the development of metal halide perovskites and perovskite-related materials as down conversion phosphors for optically pumped WLEDs. We also highlight some major issues and challenges that need to be addressed to enable perovskite-based light emitters to possibly replace currently used rare-earth doped inorganic phosphors and quantum dots.