Facilitating White Light Emission through Heterovalent Sr²⁺-Doped Nanocrystals for Visible Light Transparent Electronics

Electric lighting accounts for nearly 15% of the power consumption globally, and so it is important to develop low-cost lighting technologies. Here, we report a combined experimental and theoretical study of the optoelectronic properties of heterovalent, i.e., Sr2+-doped, Cs2AgInCl6 nanocrystals. A significant enhancement in the photoluminescence quantum yield is observed with Sr-doping concentration up to ∼6.25%. Improved optoelectronic properties are shown to originate from a combined replacement of both In and Ag sites by the Sr atoms doped into the lattice. Further, we showcase a perovskite–perovskite composite (Cs2Sr2xAg1–xIn1–xCl6:(DAO)Sn2I6)) to produce pure white light without halide segregation and transparent to visible light. The obtained white light rendered a perfect white light CIE coordinate of (0.33, 0.34) along with a luminous efficacy of radiation of ∼229 Im/W and a color rendering index of 94, proving to be the best among the lead-free halide perovskite white light emitting diodes so far.