Bi³⁺ -activated dual-wavelength emitting phosphors toward effective optical thermometry

Optical thermometry as an important local temperature-sensing technique, has received increasing attention in scientific and industrial areas. However, it is still a big challenge to develop luminescent materials with self-activated dual-wavelength emissions toward high-sensitivity optical thermometers. Herein, a novel ratiometric thermometric strategy of Bi3+-activated dual-wavelength emission band was realized in the same lattice position with two local electronic states of La3Sb1-xTaxO7:Bi3+(0 <= x <= 1.0) materials based on the different temperature-dependent emission behaviors, benefiting from the highly-sensitive and regulable emission to the coordination environment of Bi3+. The structural and spectral results demonstrate that the emission tremendously shifted from green to blue with 68 nm and the intensity was enhanced 2.6 times. Especially, the visual dual-wavelength emitting from two emission centers was presented by increasing the Ta(5+)substitution concentration to 20% or 25%, mainly originating from the two local electronic states around the Bi3+ emission center. Significantly, the dual-wavelength with different thermal-quenching performance provided high-temperature sensitivity and good discrimination signals for optical thermometry in the range between 303 and 493 K. The maximum relative sensitivity reached 2.64%/K (La3Sb0.8Ta0.2O7:0.04Bi(3+)@383 K) and 1.91%/K (La3Sb0.75Ta0.25O7:0.04Bi(3+)@388 K). This work reveals a rational design strategy of different local electronic states around the single-doping multiple emission centers towards practical applications, such as luminescence thermometry and white LED lighting. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.