Characteristics of CuInS2/ZnS quantum dots and its application on LED

In this research, CuInS2 quantum dots (QDs) have been studied as an excellent red emitting source for white LED because of its non-toxic deep red emission, and large Stokes shift properties. The CuInS2 QDs are synthesized by the one-pot method, which is a candidate for the mass-production method. In addition, formation of ZnS shells on QD surfaces has been conducted in order to reduce non-radiative recombination on its surface defects. The photoluminescence (PL) characteristics of core/shell quantum dot show that the maximum PL wavelength blue-shifts by about 80 nm on increasing its intensity more than 6 times. Quantum yield (QY) of the CuInS2/ZnS QDs shows about 67% as the maximum value. The dispersion of the quantum dots in polystyrene, which is hydrophobic and transparent, was also conducted using co-dispersing toluene. Finally, the polystyrene/quantum dot composite was applied on blue LEDs and it showed luminous efficacy of 10.7 lm/W and (0.4338, 0.1827) CIE coordinates.