Stable White Light-Emitting Diodes using Metal Halide Perovskites*

Inorganic lead halide perovskite nanocrystals (NCs) are emerging as attractive materials for their applications in modern lighting technologies due to their excellent optoelectronic properties. However, the inclusion of toxic element (lead) and stability issues in the perovskite NCs hinder their practical applications in the devices. Here, we report on the transformation of lead halide perovskite NCs to lead depleted (by 20 %) perovskite NCs and incorporation of lead depleted perovskite NCs in the commercially available polymers. As a result, the composites retain the excellent optical properties without degrading photoluminescence quantum yield. Furthermore, we have fabricated white light-emitting diodes (WLEDs) using these composites. Bright white light is achieved with superior color quality. Thus, this work demonstrates that the halide perovskite NCs are promising alternatives to conventional phosphors for the fabrication of efficient, less-toxic, and stable WLEDs.