A novel single-phase color tunable LiYGeO 4 :Dy 3+ , Eu 3+ phosphor exhibiting warm white light and excellent thermal stability.

LiYGeO 4 phosphors doped with Dy 3+ and Eu 3+ ions were synthesized using the solid phase method, and their color characteristics were adjustable. The bandgap value of LiYGeO 4 calculated by diffuse reflection data is very close to the theoretical value of 3.669 eV, indicating that LiYGeO 4 is an ideal candidate for doped rare earth activated ions. The analysis of the emission spectra and fluorescence attenuation curves of Dy 3+ and Eu 3+ co-doped LiYGeO 4 phosphors revealed a clear energy transfer process: energy transfer from Dy 3+ to Eu 3+ . Analysis of emission spectra and fluorescence attenuation curves revealed a transfer of energy from Dy 3+ to Eu 3+ . This transfer mechanism is attributed to the dipole-dipole interactions. In addition, by constantly adjusting the doping levels of Dy 3+ and Eu 3+ , a warm white phosphor with a color temperature of 3881 K was obtained. Finally, the emission intensity of the LiYGeO 4 :0.015Dy 3+ ,0.02Eu 3+ phosphor at 423 K was 86%, indicating that the phosphor has excellent thermal stability and 40% internal quantum efficiency, which proves the potential application of the LiYGeO 4 phosphor in white light-emitting diodes (w-LEDs).