Sunlike Full-Spectrum White Light-Emitting Diodes Based on Efficient and Eco-Friendly Hybrid Copper Halide Ionic Crystals

White light-emitting diodes are regarded as a substitute for traditional incandescent lights, becoming promising solid-state light sources. However, the insufficiency of rare earth elements, environmental problems caused by element mining, and an inadequate color rendering index for high-saturation colors restrict long-term application. Herein, a kind of sunlike full-spectrum white light-emitting diodes is successfully prepared, consisting of two complementary-color low-toxicity copper-based materials, which demonstrates an excellent color rendering index. Two types of eco-friendly hybrid copper halide ionic crystals with broadband emission are synthesized via cooling crystallization, exhibiting near unity photoluminescence quantum yields. Different thermal-assisted self-trapped exciton emission mechanisms result in distinctive temperature-dependent photoluminescence, both of which possess robust resistance against thermal quenching and good stability under UV laser irradiation. The white light-emitting diode devices were fabricated with an appropriate ratio of two kinds of phosphors, which show splendid rendering index, R a of 93, and R 9 of 86 simultaneously, and operational half-lifetime of 140 h under a continuous 250 mA current mode. The results provide an approach for achieving healthy lighting using environmentally friendly materials.