CdTe quantum dots and YAG hybrid phosphors for white light-emitting diodes.

CdTe quantum dots, 3.28 nm in size, were synthesized using a one-step method in an aqueous medium. The CdTe quantum dots were successfully employed as hybrid phosphors for white light-emitting diode (LED) devices by combining them with yellow-emitting YAG:Ce phosphor. The color-rendering index value and International Commission on illumination coordinates for hybrid phosphor white LEDs were 75 and (x = 0.30, y = 0.29), respectively. Compared with conventional phosphors, semiconductor quantum dots have larger band gap energy and broader absorption features, and can be excited more efficiently by optical pumping sources. The results confirmed that the high color-rendering index value of the white LED was due to the CdTe quantum dots introduced in the hybrid phosphor system.