高色纯度白光LED用蓝光材料Gd2MgTiO6∶Bi^3+的合成及性能

采用高温固相法合成了一系列蓝光荧光粉Gd2-xMgTiO6∶xBi3+(0.0025≤x≤0.015),并对样品的表面形貌、晶体结构、发光性能和热稳定性进行了探究。SEM测试结果显示,样品Gd2MgTiO6∶Bi3+的粒径分布范围大,颗粒尺寸在1~5μm范围。XRD测试表明,Bi3+成功掺杂进入基质Gd2MgTiO6中且无杂相产生。荧光光谱测试结果表明,在375 nm波长激发下,蓝光荧光粉Gd2MgTiO6∶Bi3+于385~500 nm波长范围内呈现出属于Bi3+的1S0→3P1能级跃迁的窄带发射峰,且发射强度最大处位于418 nm,这有利于避免光的重吸收现象。不同掺杂浓度下样品的发射光谱研究表明,最佳Bi3+掺杂浓度为x=0.0075。此外,发光强度最佳的蓝光样品Gd1.9925MgTiO6∶0.0075Bi3+的CIE坐标为(0.1629,0.0364),位于蓝光区域,色纯度高达96.42%,平均荧光寿命高达11.29 ms。样品的热稳定性高于文献报道的同类样品。这些均说明该样品是一种发光性能和热稳定性能良好的W-LEDs用蓝光组分。

High Color Purity Blue Emitting Phosphors Gd2MgTiO6∶Bi^3+for White Light Emitting Diodes:Synthesis and Luminescence Properties

A series of blue-emitting phosphors Gd2-xMgTiO6∶xBi3+(0.0025≤x≤0.015)were synthesized by high-temperature solid state method,and the corresponding morphology,crystal structure,photoluminescence properties and thermal stability were investigated.The scan electron microscope(SEM)test predicted that the samples Gd2MgTiO6∶Bi3+possessed a large particle size distribution with the particle size ranging from 1μm to 5μm.The X-ray diffraction(XRD)analysis showed that the Bi3+ions successfully doped into host lattice Gd2MgTiO6 with no other impurity phase existed.The photoluminescence properties stated that the blue emitting phosphors Gd2MgTiO6∶Bi3+presented a single narrow emission peak located at about 418 nm assigned to the 1S0→3P1 transition in the range from 385 nm to 500 nm in the excitation of 375 nm,which helped to avoid light reabsorption.Moreover,when the doping concentration of Bi3+ions is 0.0075,the emission intensity reaches the maximum.The sample Gd1.9925MgTiO6∶0.0075Bi3+with best photoluminescence properties exhibited a Commission Internationale De I'eclairage(CIE)coordinates of(0.1629,0.0364)in blue-light area with an impressive color purity up to 96.42%and an impressive average lifetime of 11.29 ms.In addition,the thermal stability of sample Gd1.9925MgTiO6∶0.0075Bi3+was relatively higher than that of similar blue-emitting phosphors in the literature.These results indicated that sample Gd1.9925MgTiO6∶0.0075Bi3+is a kind of blue-emitting component for W-LEDs with excellent luminescence and thermal stability.