Design of dual-mode optical temperature sensing in single-component white light emission Bi3+/Sb3+/Ho3+ tri-doped Cs2Ag0.2Na0.8LuCl6 double perovskites

The single-component white light emission microcrystals were synthesized in Bi 3+ /Sb 3+ /Ho 3+ ions tri-doped Cs 2 Ag 0.2 Na 0.8 LuCl 6 double perovskites by a simple precipitation method. In Bi 3+ /Sb 3+ ions double-doped Cs 2 Ag 0.2 Na 0.8 LuCl 6 microcrystals, the tunable emission from yellow (Bi 3+ ) to blue (Sb 3+ ) can be achieved under ultraviolet light excitation. Particularly, the white light emission is obtained after doping Ho 3+ ion because of the energy transfer processes of Bi 3+ →Ho 3+ and Sb 3+ →Ho 3+ . The chromaticity coordinates (CIE) of Cs 2 Ag 0.2 Na 0.8 LuCl 6 :5 mol% Bi 3+ ,1 mol% Sb 3+ ,15 mol% Ho 3+ microcrystal are (0.3354, 0.3394) under 315 nm excitation. Meanwhile, the white light emissions with different color temperatures are obtained through varying the excitation wavelength (255–365 nm). Additionally, temperature-dependent fluorescence spectra show that the emission intensity of Bi 3+ /Sb 3+ /Ho 3+ tri-doped Cs 2 Ag 0.2 Na 0.8 LuCl 6 microcrystal at 423 K remains 54% of that at 303 K. Moreover, the fluorescence intensity ratio (FIR) of 641 and 665 nm is highly temperature-dependent, the relative sensitivity ( S r ) reaches 1.06%/K at 303 K under 315 nm excitation. Simultaneously, the microcrystal shows thermochromism phenomenon, and the emission changes from white to blue-purple with the increase of temperature from 303 to 513 K. The novel temperature sensing is achieved based on CIE coordinates and temperature technology in Cs 2 Ag 0.2 Na 0.8 LuCl 6 :5 mol% Bi 3+ ,1 mol% Sb 3+ ,15 mol% Ho 3+ microcrystal by exciting at 315 nm. The corresponding maximum S r is 0.34%/K. Accordingly, Bi 3+ /Sb 3+ /Ho 3+ ions tri-doped Cs 2 Ag 0.2 Na 0.8 LuCl 6 double perovskite has potential applications in the fields of white light emitting diode and optical temperature sensing.