Ce:YAG荧光陶瓷掺杂Gd对白光LED发光性能的影响

Ce: YAG荧光陶瓷具有突出的导热性及化学稳定性, 相比有机硅胶封装法在高功率白光LED的应用上具有更广阔的应用前景。本研究采用真空固相烧结法制备了不同Gd掺杂浓度的(Gd, Y)₃Al₅O₁₂:Ce样品, 通过XRD, SEM及荧光光谱等表征手段, 研究了Gd掺杂对Ce:YAG荧光陶瓷的晶体结构及其用于白光LED时对发光性能的影响。实验表明, 随着Gd掺杂浓度的提高, Gd³⁺取代Y³⁺ 的位置进入晶格, 使得样品的晶格常数增加。Gd³⁺还影响了Ce³⁺对蓝光的吸收, 同时Ce³⁺将蓝光转换成黄光的效率也下降, 导致光效从81.45 lm/W降低至63.70 lm/W。Gd的掺 杂使Ce³⁺的光致发光谱峰位从534 nm向564 nm红移, 显色指数从61.3提升至70.2。Gd的掺杂虽然降低了发光 效率, 但显著提高了(Gd, Y)₃Al₅O₁₂:Ce样品的显色指数, 使得黄色YAG荧光陶瓷应用于白光LED的性能得到了 提高。

Luminescence Characteristics of Ce: YAG Ceramic Phosphors with Gd3+ Doping for White Light-emitting Diodes

Ce:YAG ceramic phosphor has outstanding thermal conductivity and chemical stability for application in white light-emitting diodes (WLEDs), thus has a broader application than organic packaging in high-power WLEDs. (Gd,Y)₃Al₅O₁₂:Ce ceramic phosphors of varying Gd³⁺ concentrations were fabricated through solid-state reactive sintering method. Through X-ray diffraction, scanning electron microscopy, and fluorescence spectroscopy, the crystal structures, influence of the Gd concentration on fluorescence spectra of Ce:YAG, and luminescence properties of WLEDs with (Gd,Y) ₃Al₅O₁₂:Ce ceramic phosphors were investigated. As Gd content increased, the Gd³⁺ replaced the lattice position of Y³⁺ into the lattice. The absorption of blue light and relative photoluminescence (PL) intensity of the (Gd,Y)₃Al₅O₁₂:Ce ceramic phosphors decreased as Gd content increased, leading to a reduction in the luminous efficacy from 81.45l m/W to 63.70l m/W. Moreover, the PL emission bands of (Gd,Y)₃Al₅O₁₂:Ce exhibited redshift from 534 nm toward 564 nm and resulted in increase of the color, rendering index from 61.3 to 70.2. Although doping of Gd decreases the luminous efficacy, the color rendering index of the (Gd,Y)₃Al₅O₁₂:Ce sample is significantly increased, and the performance of the yellow YAG ceramic phosphor applied to the white LED is improved.