基于Cu掺杂ZnInS和ZnCdS量子点的高显色性白光LED

利用胶体化学方法合成了发光波长可调的Cu掺杂量子点, 其波长范围可从绿光到深红光连续调节.通过将绿光ZnInS :Cu和红光ZnCdS :Cu量子点与蓝光GaN芯片相结合, 制备了高显色性的白光LED, 其流明效率为71 lm·W^-1, 色温为4 788 K, 显色指数高达94, CIE色坐标为(0.352 4, 0.365 1).通过测量Cu掺杂量子点的荧光衰减曲线, 发现不存在从绿光ZnInS :Cu到红光ZnCdS :Cu量子点的能量传递过程, 因为红光ZnCdS :Cu量子点在绿光波段没有吸收. 实验结果表明, Cu掺杂量子点有望应用于固态照明领域.

High Color Rendering White-light-emitting Diodes Based on Cu-doped ZnInS and ZnCdS Quantum Dots

Cu-doped quantum dots (QDs) were used as color converting materials for preparing efficient white light-emitting diodes (LEDs). The Cu-doped QDs synthesized by chemical method showed composition-tunable emission from green to deep red and large Stokes shifts. By using the combination of green light-emitting ZnInS :Cu QDs and red emitting ZnCdS :Cu QDs with blue GaN chips, a high color rendering white LED was fabricated. The resulting three-band RGB QD-white LED exhibits high performance with luminous efficacy of 71 lm/W, color rendering index up to 94, CIE-coordinates of (0.352 4, 0.365 1), and color temperature of 4 788 K. Based on the changes in the photoluminescence lifetimes of Cu-doped QDs, it is found that the energy transfer process from green ZnInS :Cu QDs to red ZnCdS :Cu QDs can be negligible, because the red QDs had no absorption at green band. These results suggest that Cu-doped QDs are promising for solid state lighting.