Multicolor and multimode luminescent lanthanide-doped Cs2NaInCl6:Sb3+ from visible to near infrared for versatile applications

Double halide perovskites have shown admirable potential in promising optoelectronic applications due to simple synthesis, good stability and high structural tolerance. However, the poor optical properties caused by the parity-forbidden transitions posts a stringent limitation on their potential applications. Herein, we dope the lanthanide (Ln³⁺) ions with abundant energy levels into the Cs₂NaInCl₆:Sb³⁺ single crystals, which not only achieve multicolor visible emissions spectra from blue to red light, but also expand to the near infrared region from 800 to 1900 nm. In addition, the phosphors enable the multimode emissions with the up-conversion and down-conversion photoluminescence. Intriguingly, the excitation source, and the excitation light intensity also endow the multicolor emissions. Thus, combining with the multicolor and multimode luminescent properties, Cs₂NaInCl₆:Sb³⁺/Ln³⁺ could be applied to night vision imaging, substance detection, optical thermometry, white-light-emitting diodes (WLEDs) and anti-counterfeiting. The maximum value of relative temperature sensitivity reaches as high as 1.207 % K⁻¹, which is relatively higher than those of most metal halide perovskites. Moreover, the single-source WLED displays Commission Internationale de L'Eclairage color coordinates (0.32, 0.31), a correlated color temperature of 6673 K, and color rendering index of 81.7. These results demonstrate the potential applications in the multifunctional photoelectric applications.