Enhanced luminous efficacy of transparent Ce3+:YAG ceramics with “light-scattering centres” prepared by uniform Ce:Y2O3 submicron spheres for WLEDs

Transparent Ce3+:YAG ceramics have great potentials in WLEDs due to their ultra-high thermal endurance property and thermal stability of luminescence. However, it is still a challenging issue to enhance their light extraction ability. In the study, the transparent Ce3+:YAG ceramics were fabricated using the uniform Ce:Y2O3 submicron spheres by a solid-state reactive sintering method under vacuum without any sintering additives. The content of the residual pores and grain boundaries, which acted as the “light-scattering centres” to improve the absorption of blue light, were adjusted by changing sintering temperature. The luminous efficacy of the WLED with the sample sintered at 1700 °C was as high as 104.6 lm/W, due to the appropriate quantity of the “light-scattering centres”. The microstructures, transmittance, excitation and emission spectra, luminous characteristics of the samples were studied. The results showed that the preparation progress could significantly enhance the luminous efficacy in the WLED with transparent ceramics.