GdAl3(BO3)4:Cr3+ is used to fabricate a NIR-pc-LED that shows promise for plant lighting and applications in the nondestructive analysis of agricultural products.

All-inorganic lead-free perovskite-derivative metal halides have shown great promise in optoelectronics, however, it remains challenging to realize efficient near-infrared (NIR) luminescence in these materials. Herein, we report a novel strategy based on Te 4 + /Ln 3 + (Ln = Er, Nd, and Yb) co-doping to achieve efficient NIR luminescence in vacancy-ordered double perovskite Cs 2 ZrCl 6 phosphors, which are excitable by a low-cost near-ultraviolet light-emitting diode (LED) chip. Through sensitization by the spin-orbital allowed 1 S 0 ! 3 P 1 transition of Te 4 + , intense and multi-wavelength NIR luminescence originating from the 4f!4f transitions of Er 3 + , Nd 3 + , and Yb 3 + was acquired, with a quantum yield of 6.1 % for the Er 3 + emission. These findings provide a general approach to achieve efficient NIR emission in lead-free metal halides through ns 2metal and lanthanide ion co-doping, thereby opening up a new avenue for exploring NIR-emitting perovskite derivatives towards versatile applications such as NIR-LEDs and bioimaging.

K2TiF6:Mn4+ is a highly efficient narrow‐band emission red phosphor with promising applications in white light‐emitting diodes (LEDs) and wide‐gamut displays. Nevertheless, the poor moisture‐resistant properties of this material hinder commercialization. A convenient reverse cation‐exchange strategy is introduced for constructing a core–shell‐structured K2TiF6:Mn4+@K2TiF6 phosphor. The outer K2TiF6 shell acts as a shield for preventing moisture in the air from hydrolyzing the internal MnF62− group, while effectively cutting off the path of energy migration to surface defects, thereby increasing the emission efficiency (especially for the phosphors doped with high concentrations of Mn4+). Employed as a red phosphor, the packaged white LED exhibits an extraordinarily high luminous efficacy of 162 lm W−1, a correlated color temperature (CCT) of 3510 K, and a color rendering index of 93 (Ra). Aging tests performed on this device at 85 °C and 85 % humidity for 480 h retain up to 89 % luminous efficacy. The findings could facilitate commercial application of K2TiF6:Mn4+@K2TiF6 phosphor.