基于铈钆共掺杂YAG单晶荧光片的高光效白光LED

为了满足高功率白光发光二极管(Light-Emitting Diode,LED)对荧光体的高性能要求,对白光LED用Cex Gd:YAG单晶荧光材料的制备和光学、电学、热学特性进行了研究.采用提拉法生长了CexGd:YAG(x=0.02,0.04,0.06,0.08)单晶,并借助于X射线衍射(XRD)、吸收光谱、发射光谱等对晶体的光谱特性进行了表征,同时也测试分析了相对荧光强度随温度的变化关系、基于不同Ce3+浓度Cex Gd:YAG单晶的白光LED性能参数.结果表明Cex Gd:YAG单晶在450 nm的蓝光激发下,产生一个500～650 nm的宽峰发射,在100℃高温下,其荧光光强比商用荧光体粉末高出10;.当Ce3+浓度为6;时,采用Cex Gd:YAG单晶荧光片的白光LED光效高达153 lm/W,是Ce:YAG和树脂荧光材料白光LED的两倍多.Cex Gd:YAG单晶荧光片,具有更高更稳定的荧光光强,制作的白光LED光效有明显提升,有望成为新型的商用荧光体.

High Luminous Efficacy White LED Based on Cex,Gd Co-doped YAG Single Crystal Phosphors

In order to meet the high performance requirements of phosphors for high-power white light-emitting diode(LED),preparation and optical,electrical and thermal properties of CexGd∶YAG single crystals fluorescent materials for white LED were studied.The CexGd:YAG(x=0.02,0.04,0.06,0.08)single crystals were grown by the Czochralski method,and its luminescence properties were characterized via the XRD patterns,absorption and emission spectra.The temperature dependence of relative florescent light intensity and the performances of white LEDs fabricated by CexGd:YAG single crystals with different Ce3^+ concentration were also analyzed.The results indicate that when CexGd:YAG crystal is excited by 450 nm blue light,a broad emission band of 500-650 nm range is produced,and the luminescence intensity is 10% higher than commercial phosphor at 100℃.When the Ce^3+ concentration is 6%,the efficacy of white LED fabricated by CexGd:YAG single crystals is up to 153 lm/W,more than twice the efficacy of white LED with Ce:YAG-resin composite.CexGd:YAG single crystals have higher and more stable florescent light intensity,and the efficacy of white LED has been greatly improved.CexGd:YAG single crystals is expected to become a new type of commercial fluorescent material.