Dual-Mode Manipulating Multicenter Photoluminescence in a Single-Phased Ba 9 Lu 2 Si 6 O 24 :Bi 3+ , Eu 3+ Phosphor to Realize White Light/Tunable Emissions.

A Bi ³⁺ and Eu ³⁺ ion co-doped Ba ₉ Lu ₂ Si ₆ O ₂₄ single-phased phosphor was synthesized successfully via a conventional high-temperature solid-state reaction. X-ray diffraction, crystal structure analysis, diffuse reflectance and luminescent spectra, quantum efficiency measurements, and thermal stability analysis were applied to investigate the phase, structure, luminescent and thermal stability properties. From the analyses of the crystal structure and luminescent spectra, we observed four discernible Bi ³⁺ luminescent centers with peaks at ~363.3, ~403.1, ~437.7, and ~494.5 nm. Moreover, due to the complex energy transfer processes among these Bi ³⁺ centers, their relative emission intensity tightly depended on the incident excitation wavelength. Interestingly, the as-prepared phosphor could generate warm white light/tunable emission by changing the concentration of Eu ³⁺ ions or adjusting the excitation wavelength. The energy transfer mechanism from Bi ³⁺ to Eu ³⁺ was confirmed via an electric dipole-dipole interaction, the energy transfer efficiencies [Formula: see text] from Bi ³⁺ to Eu ³⁺ were 50.84% and 40.17% monitoring at 410 and 485 nm, respectively. The internal quantum efficiency of the optimized Ba ₉ Lu ₂ Si ₆ O ₂₄ :Bi ³⁺ , Eu ³⁺ phosphor was calculated to be 42.6%. In addition, the configurational coordinate model was carried out to explain the energy decrease of the phonon-electron coupling effect.