Tunable Emission in Bi/Te-Doped Rb₂ZrCl₆ Crystals for White Lighting

Wide-spectrum tunability is of great importance for the design of white light-emitting materials. The vacancy-ordered double perovskite hosts are suitable for incorporating emissive dopant ions to produce white emissions due to their high impurity tolerance and electronically "zero-dimensional" nature. This study presents a Bi/Te-doped Rb₂ZrCl₆ phosphor with a double perovskite structure, displaying a wide-band light emission covering 400-700 nm. Optical characterization reveals that the wide emission consists of blue and yellow emissions centered at 450 and 560 nm, stemming from host- and/or dopant-induced self-trapped excitons. Due to the independent luminescence processes of the self-trapped excitons, an exceptional color tunability can be achieved flexibly through a change of either the dopant concentrations or the excitation wavelengths. Given the good stability, great color tunability, and wide-band emission, the study on Bi/Te-doped Rb₂ZrCl₆ phosphors establishes a viable way for the development of single-phase phosphors capable of emitting white light with specific correlated color temperatures.