电荷补偿对红色LED用荧光粉体的荧光性能改进

通过高温动态球磨固相法, 采用三种电荷补偿方式: (a) 3Ca2+/Sr2+→2Eu3+/Gd3++空穴; (b) 2Ca2+/Sr2+→2Eu3+/Gd3++M+(M+=Li+, Na+, K+中的一种或多种离子); (c) Ca2+/Sr2+→2Eu3+/Gd3++X-(X-=F-, Cl-, Br-, I-), 制备了红色发光二极管(LED)荧光粉体Ca0.54Sr0.16-δEu0.08Gd0.12(MoO4)0.2(WO4)0.8(δ=0-0.16). 研究表明, 方法(b)是一种较优的电荷补偿方式. 利用此荧光粉和390-405 nm发射LED芯制备了红色LED, 当正向驱动电流为20 mA时, 色坐标为x=0.66, y=0.33; 色纯度100%; 光强达6200 cd·m2; 发光效率约为95 lm·W-1. 器件的色坐标和显色指数等参数随正向驱动电流的变化起伏很小, 颜色稳定. 该红光荧光粉在新一代白色LED照明领域具有广阔应用前景.

Improved Luminous Properties of Red Emitting Phosphors for LED Application by Charge Compensation

Froma dynamic ball-grinding solid-state reaction, a series of red-emitting phosphors Ca0.54Sr0.16-δEu0.08Gd0.12 (MoO4)0.2(WO4)0.8 (δ=0-0.16) were synthesized by charge compensation. Three approaches to charge compensation were used and are (a) 3Ca2+/Sr2+→2Eu3+/Gd3++vacancy; (b) 2 Ca2+/Sr2+→2Eu3+/Gd3++M+, where M+ is a monovalent cation like Li+, Na+, or K+ employed as a charge compensator; (c) Ca2+/Sr2+→2Eu3+/Gd3++N-, where N- is a monovalent anion like F-, Cl-, Br- or I- employed as a charge compensator. The results showed that model (b) was better at charge compensation. One red light-emitting diode (LED) was made by combining a phosphor with a 390-405 nm emitting LED chip under a 20 mA forward-bias current. The chromaticity coordinates (CIE), color purity, light intensity, and luminous efficiency were x=0.65, y=0.33, 100%, 6200 cd·m2, and 95 lm·W-1, respectively. Furthermore, the CIE and color purity of the apparatus changed little and the color was stable. This red-emitting phosphor in the field of new generation white-light LEDs has broad application prospects.