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

Transparent Ce 3+ :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 Ce 3+ :YAG ceramics were fabricated using the uniform Ce:Y 2 O 3 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.