Two-step sintered phosphor ceramics for high-power LED applications: Fine microstructure and luminescent property

With the development of the high-power solid-state lighting (SSL) industry, there is an urgent demand for low-cost color converters with good luminescent performance and thermal robustness. Conventional phosphor ceramics face the problems of high sintering energy consumption and low light extraction efficiency. In the present work, a two-step sintering (TSS) method has been developed to obtain a series of YAG:Ce and YAG:Ce-Al2O3 samples at a lower temperature of 1600 °C, where the operating power is reduced to 67% of the traditional one-step process. The TSS samples have a fine microstructure, which leads to a better scattering enhancement effect. The impacts of grain size and composition on optical and thermal properties were investigated in detail. The luminous characteristics and stability were analyzed by packaging phosphor ceramics with blue LEDs, with a maximum LE of 188.72 lm/W, CRI of 58.7, and CCT in the range of 3628–5048 K, respectively. Such suitable properties of the TSS material make it a promising candidate for high-power white LEDs applications.