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。

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.