Improving the thermal stability of Pr3+-based niobate phosphor by adjusting the energy level of intervalence charge transfer band

Currently, the thermal quenching effect is still a pain point limiting the application of luminescent materials at high temperatures, and therefore it is of great significance to explore schemes with a well-defined mechanism to regulate the thermal quenching of phosphors. In this work, a controllable regulation of the energy level positions of the intervalence charge transfer bands was achieved by modifying the Sr/Ca ratio of Sr 1-x Ca x Nb 2 O 6 :0.005Pr 3+ . With the increase of x from 0.00 to 1.00, the IVCT energy level decreases from 4.03 eV to 3.96 eV, which leads to the easier transfer of 3 P 0 electrons of Pr 3+ to the 1 D 2 energy level through the IVCT band during the heating process, and thus realizes the enhancement of the thermal stability of the 1 D 2 emission, which is shown by the increase of the integrated emission intensity of 1 D 2 at 573 K compared with that of 298 K from 22.87 % (x = 0) to 98.89 % (x = 1) gradually. In particular, CaNb 2 O 6 :0.005Pr 3+ with the lowest IVCT energy level achieves a high degree of thermal stability, with the integrated emission intensity consistently maintained at 98.1%–103.6 % at 298K–573K. In addition, the phosphor's has potential for thermochromic and optical thermometry applications. This work shows the reliability of modulating the IVCT band energy level positions to realize the antithermal quenching of phosphors and its promising applications.