Effects of Annealing on the Photoluminescence Properties of Citrate-Capped YVO₄:Bi³⁺,Eu³⁺ Nanophosphor

Abstract

We investigated the effects of annealing on the photoluminescence (PL) properties of a citrate-capped YVO4:Bi3+,Eu3+ nanophosphor. The 300 °C annealed nanophosphor exhibited the highest PL intensity at 619.5 nm corresponding to an f–f transition of Eu3+ under near-UV excitation. Fourier transform infrared spectroscopy indicated a decrease in the amounts of adsorbed water and citrate on the nanophosphor surface with annealing. Dehydration and the increase in near-UV absorption contributed to the improved PL intensity, since water is a Eu3+ luminescence quencher. The thermal decomposition of citrate, which photoreduces vanadate under near-UV irradiation, caused the improved photostability. Annealing at ≥400 °C decreased the PL intensity. A color change from white to yellow may be attributed to absorption by byproducts, possibly formed by the segregation of YVO4:Bi3+,Eu3+. A shorter PL lifetime and lower activation energy of thermal quenching at higher annealing temperature were confirmed from PL decay curves and the temperature dependence of PL intensity, respectively. The formation of surface defects resulted from the thermal decomposition of adsorbed citrate. The decrease in PL intensity was caused by the formation of byproducts and surface defects.

Effects of Halide Composition on the Self-Recovery of Photodegraded Cesium Lead Halide Perovskite Nanocrystals: Implications for Photoluminescence Applications

“…Photodegradation is a significant problem for many luminescent nanomaterials, e.g., lanthanide-doped oxide nanocrystals, such as Y 3 Al 5 O 12 :Ce 3+ and YVO 4 :Bi 3+ ,Eu 3+ , − and ZnS-shelled semiconductor nanocrystals of CdSe, CdTe, CuInS 2 , InP, and ZnS:Mn 2+ . − Many studies investigating the suppression of photodegradation have focused on preserving the initial PL properties of the material; however, recovery of the photodegraded nanophosphors has not been a primary objective because photodegradation has generally been considered an irreversible phenomenon. Recently, our group reported on the complete self-recovery of CsPbBr 3 NCs after drastic degradation by light excitation .…”

Effects of Weak Electric Field on the Photoluminescence Behavior of Bi3+-Doped YVO4:Eu3+ Core–Shell Nanoparticles

“…YVO 4 core NPs were synthesized using a modified hydrothermal route and then annealed at 300 °C for 2 h to volatilize the absorbed citrate and hydroxyl ions and improve crystallinity. 61 The different nanoarchitectures studied here are shown in Table 1. The Eu 3+ -doped YVO 4 core NPs were synthesized without (C1) and with (C2) the addition of Bi 3+ to demonstrate the relationship between the hybridization of Bi 3+ with VO 4 3− ions and its effect on Eu 3+ ion luminescence.…”

Structural, optical and special spectral changes of Dy3+ emissions in orthovanadates

“…Yoshiki Iso et al have reported a detailed mechanism behind the decrement in PL intensity due to the thermal treatment for YVO 4 :Eu 3+ , Bi 3+ phosphor. 41 Herein, the decrease in PL intensity above 600 C could be due to the fact that during hightemperature synthesis, the excess thermal energy deteriorated the crystallinity which caused in a distortion of the crystal eld rather than enhancing the atomic arrangement for the recrystallization. Furthermore, the change in morphology could also be the reason to decrease the PL intensity.…”