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Construction of thermally stable Tb3+-activated green-emitting phosphors: dual driving strategy of doping concentration and excitation wavelength

  • 0Department of Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China. guoning@usst.edu.cn.
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February 22, 2024

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February 22, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Achieving stable green light emission from Tb<sup>3+</sup>-doped phosphors at high temperatures is difficult. This study shows that doping concentration and excitation wavelength can effectively control thermal quenching in Gd<sub>1-</sub>TaO<sub>4</sub>:<i>x</i>Tb<sup>3+</sup> phosphors.

Area Of Science

  • Materials Science
  • Solid-State Chemistry
  • Luminescence

Background

  • Thermally stable Tb<sup>3+</sup>-doped green emission is crucial for solid-state lighting but remains a significant challenge.
  • Modulating luminescence stability at high temperatures requires further investigation.

Purpose Of The Study

  • To systematically investigate the thermal quenching performance of Tb<sup>3+</sup>-activated Gd<sub>1-</sub>TaO<sub>4</sub> phosphors with varying doping concentrations.
  • To explore the influence of intervalence charge transfer (IVCT) energy levels and excitation wavelengths on luminescence stability.

Main Methods

  • Synthesis of Gd<sub>1-</sub>TaO<sub>4</sub>:<i>x</i>Tb<sup>3+</sup> phosphors (<i>x</i> = 0.1%, 0.5%, 2%) with varying Tb<sup>3+</sup> concentrations.
  • Determination of IVCT energy levels using empirical formulas and spectral measurements (excitation and diffuse reflectance).
  • Analysis of thermal quenching performance via variable-temperature spectra and fluorescence lifetimes under different excitation conditions.

Main Results

  • IVCT energy levels showed a decreasing trend with increasing Tb<sup>3+</sup> concentration.
  • Thermal quenching performance varied significantly with excitation wavelength (host absorption, Tb<sup>3+</sup> 4f-5d, and Tb<sup>3+</sup>-Ta<sup>5+</sup> IVCT band).
  • Quantum efficiency increased with Tb<sup>3+</sup> concentration, explained by a model of compensating and quenching channels and Tb<sup>3+</sup> to Gd<sup>3+</sup> energy conversion.

Conclusions

  • The dual strategy of optimizing doping concentration and excitation wavelength effectively regulates the thermal quenching performance of Tb-activated green-emitting tantalate phosphors.
  • Understanding IVCT energy levels is key to modulating high-temperature luminescence stability.