Efficient Multicolor and White Photoluminescence in Erbium- and Holmium-Incorporated Cs₂NaInCl₆:Sb³⁺ Double Perovskites

Inorganic lead-free halide perovskites with a broad-band emission of self-trapped excitons (STEs) have attracted great attention in lighting applications. However, it remains a fundamental challenge to expand the display color gamut because it is difficult to individually tune the emitting proportion at different wavelengths. Herein, we employ a doping route to incorporate Sb3+, Er3+, and Ho3+ ions into the Cs2NaInCl6, which enables multicolor emissions with narrow full width at half-maxima and high photoluminescence quantum yields (PLQYs). The blue emission (445 nm) originates from STEs in the [SbCl6]3– octahedrons, while the narrowband green (550 nm) and red (655 nm) emissions are mainly derived from the Er3+ and Ho3+ ions, respectively. An efficient energy transfer between multiple luminescent centers is the key point to achieve such an efficient and tunable emission. By controlling the lanthanide doping level, the emission color can be systematically modulated, and cold 10401 K (0.278, 0.286) to warm 4608 K (0.347, 0.298) adjustable white-light emission (PLQY of ∼70%) can be achieved successfully. The results provide inspiration for the material design of lead-free perovskites with efficient and tunable light-emitting properties for optoelectronic applications.