Effect of boron carbide (B4C) on luminescent efficiency and thermal stability of Y3Al5O12:Ce3+ phosphors

Abstract

Achieving high efficient and thermally stable YAG:Ce3+ phosphor is ideal for assembling bright white-LEDs. In this paper, we report a new method to improve the luminescent efficiency and thermal stability of the YAG:Ce3+ phosphor by adding a proper amount of B4C. The YAG:Ce3+,xB4C phosphors were prepared via the conventional high-temperature solid-state reaction method. The phase, microstructure, luminescent properties and thermal stability of the prepared phosphors were investigated in detail. After adding B4C, the single-phase YAG:Ce3+ phosphor can be obtained at a temperature of 1350 °C, lower than that of the sample without B4C (1500 °C). The emission intensity of the sample was significantly enhanced by adding B4C. The maximum emission intensity is obtained at x = 0.05 wt%, which is enhanced by a factor of ~160%, comparing to the sample without B4C. The enhancement can be attributed to the improved Ce3+/Ce4+ ratio, the enhanced crystallinity, and the fine morphology. Moreover, the emission band exhibits a red shift due to the B3+ incorporation. Importantly, the prepared phosphor exhibits an improved thermal stability. Its emission intensity can maintain about 92% (200 °C) of its original value at room temperature, higher than that of the commercially available one (86% at 200 °C). The results reveal the addition of B4C in a proper amount is an effective way to improve the luminescent efficiency and thermal stability of the YAG:Ce3+ phosphor. This work also provides an important guidance for the synthesis of Ce3+ doped luminescent materials for white-LEDs.