Rare earth-based Cs2NaRECl6 (RE = Tb, Eu) halide double perovskite nanocrystals with multicolor emissions for anticounterfeiting and LED applications

Abstract

Metal halide double perovskites are a promising alternative to lead-based perovskites. Especially, rare earth (RE)-based halide double perovskites have attracted much attention due to their unique optical properties. As RE³⁺ ions could be served not only as the component of the matrix but also as the luminescence centers, the chemical composition of RE-based halide double perovskites can be simplified and tunable luminescence could be achieved. In this work, Cs₂NaRECl₆ (RE = Tb, Eu) halide double perovskite nanocrystals were synthesized by the hot injection method. Cs₂NaRECl₆ nanocrystals exhibit not only the intrinsic host emission but also the characteristic emissions of RE³⁺ ions. Furthermore, the excitation-wavelength-dependent multicolor emissions of Cs₂NaRECl₆ nanocrystals make them highly potential for anticounterfeiting applications. Multicolor LED devices based on various components of Cs₂NaRECl₆ could be obtained, providing promising candidates for optoelectronic applications.