Thermally stable and highly efficient Ta-doped CsV1-xO3 green-light-emitting phosphors for WLED.

Owing to their energy-saving and environmentally friendly characteristics, rare-earth-free ultraviolet-excited green-luminescent materials have garnered significant attention. To improve the luminescence efficiencies of green-luminescent materials, this study synthesized Ta-doped CsV 1-x O 3 green-light-emitting phosphors through a solid-state-reaction method, adopting an optimal Ta doping concentration of 10%. Theoretical calculations and reflection spectra revealed an intrinsic indirect band gap of 2.86 eV for CsV 0.9 Ta 0.1 O 3 , lower than that of CsVO 3 (3.63 eV). Under 365 nm excitation, the as-prepared phosphors exhibited broadband emissions ranging from 400 nm to 700 nm, attributed to the 3T 2 →1A 1 and 3T 1 →1A 1 transitions within VO 4 tetrahedra. Notably, adding Ta5+ ions to CsVO 3 increased its emission intensity by 1.39 times and induced a redshift in its excitation spectrum from 369 to 375 nm. Furthermore, Ta5+ doping significantly distorted the VO 4 tetrahedra and influenced the optical properties of the synthesized phosphors. Specifically, the nearest of Cs–V bond length increased, and weak interactions between V5+ ions and Cs + ions led to a 1.5-fold higher internal quantum efficiency (60.49%) of CsV 0.9 Ta 0.1 O 3 compared to that of CsVO 3. Furthermore, CsV 0.9 Ta 0.1 O 3 demonstrated high thermal stability, retaining 75.57% of its initial intensity even at 140 °C. Overall, these results indicate the potential applicability of CsV 0.9 Ta 0.1 O 3 as a green-emitting phosphor for white-light-emitting diode applications. [ABSTRACT FROM AUTHOR]