Facile Synthesis of Efficient Copper Chlorine‐in‐glass for White Light‐Emitting Diode and Anti‐Counterfeiting

Copper halides have attracted extensive interest because of the merits of environmental friendliness, low lost, and superior optoelectronic properties. However, the stability issue heavily hinders their commercial application. Herein, the successful synthesis of copper chlorine in glass using melting‐quenching method under vacuum condition is reported. By introducing CuCl into the glass matrix (CuCl@glass), the as‐fabricated samples emit white or yellow light, which depends on the ratios of CuCl:glass. The maximum values of the photoluminescence quantum yield are found to be 37% and 26%, respectively. With the addition of CsCl, CsCu 2 Cl 3 , and Cs 3 Cu 2 Cl 5 phases form in the glass, leading to the phosphor‐in‐glass which emits green light. A maximum luminous yield of 74% is achieved. Based on the synthesized samples, light‐emitting diodes are successfully prepared by the remote packaging technology, and the utilization of the as‐obtained composites for anticounterfeiting application is realized. Herein, an effective approach for the preparation of lead‐free halide perovskite@glass composites is provided, opening up potential commercial applications.