Realization of color-tunable emission via energy transfer in novel single-phase K3YB6O12:Bi3+, Eu3+ phosphors

Abstract

Nowadays, Bi3+→Eu3+ energy transfer behavior is a hot research topic in phosphor-converted white light emitting diodes, because it can simultaneously realize the efficient sensitization of red emission of Eu3+ and emission color adjusting. Herein, we report a series of novel Bi3+ singly doped and Bi3+/Eu3+ co-doped K3YB6O12 phosphor materials synthesized by conventional high-temperature solid-state reaction. The structural and photoluminescence properties of the as-prepared phosphors were investigated by X-ray diffraction, photoluminescence spectra and decay curves. K3YB6O12:Bi3+ phosphors exhibited a single ultraviolet-blue emission band excited by ultraviolet that corresponded to the characteristic 3P1 → 1S0 transition of Bi3+ ions and reached the highest emission intensity with the Bi3+ doping concentration of 15%. By introducing Eu3+ into K3YB6O12:0.015Bi3+ phosphor, the Bi3+ → Eu3+ energy transfer phenomenon was induced in the K3YB6O12:Bi3+, Eu3+ phosphors that resulted in broad excitation characteristic in ultraviolet region. With the Eu3+ contents increase, the Bi3+ → Eu3+ energy transfer becomes more and more efficient that leads to the color-tunable emission from ultraviolet-blue to red. In addition, the efficiency and mechanism of Bi3+ → Eu3+ energy transfer were also investigated in detail, as based on theoretical evaluations. Our results implied that the as-prepared K3YB6O12:Bi3+, Eu3+ phosphors could be suitable to be applied in white light emitting diodes.