Enhanced thermally stable performance of Pr-doped vanadate phosphor by inhibiting the intervalence charge transfer quenching channel.

Praseodymium (Pr) ion and the transition metal vanadium (V) ion with d electronic configuration can form an intervalence charge transfer (IVCT) band, which can function both as a compensatory channel for its red emission and as a quenching channel, thus affecting the luminescence thermal stability of the phosphors. Research studies reveal that the emission of Pr in the YVO matrix can be quenched by the IVCT mechanism, thereby limiting the application of phosphors. As such, the present contribution is based on the solid solution replacement strategy to inhibit the constitutent of the IVCT quenching channel and thus improve thermal stability. Therefore, phosphonium (P) with a valence state matching V and a similar ion radius was selected for the V/P substitution. It lacks a d electron configuration, preventing the formation of an IVCT band with Pr and thereby inhibiting the construction of the quenching channels to enhance thermal stability. While the empirical formula of IVCT indicates a decrease in the IVCT energy level from 3.32438 to 3.06251 eV upon the introduction of P, the PLE spectra demonstrate a sharp reduction in IVCT intensity, , weakening of the quenching channel. The thermal stability of the phosphors at different excitation locations was enhanced with the rise of P concentration. When excited at the P level, the YPO:0.5%Pr phosphor demonstrated highly stable red emission from 303 to 523 K, with a luminescence integrated intensity ranging from 95.5% to 105.3% compared to that at 303 K. This research provides a novel approach for inhibiting the IVCT quenching channel and broadens the commercial value of YVO:Pr phosphor for various applications.