Improved Color-Rendering Property of the YAG:Ce-Nanocrystalline-Phosphor-Converted White-Light-Emitting Diode Through the Addition of CuInS2/ZnS Quantum Dot

초록

The present work describes the synthesis of the YAG:Ce nanophosphor and the CuInS2/ZnS (CIS/ZnS) core/shell quantum dot (QD) and their application to the white-light-emitting diode (WLED). First, 120- to 180-nm citric-acid-assisted sol gel-derived YAG:Ce nanophosphor was obtained after 1300 degrees C annealing. Quantum-shifted CIS/ZnS QD was synthesized through a novel, facile solvothermal method and exhibited an orange band emission with a peak wavelength of 570 nm and an excellent quantum yield of 63%. Using either the nanophosphor or the QD as a color converter, WLEDs were fabricated but showed limited color-rendering properties due to the spectral deficiency in the white light that was generated. To enhance the color-rendering index (CRI) of the WLED, the nanophosphor and QD were combined into the same chip through the stacking scheme. The resulting WLED exhibited a CRI value of 86, suggesting that the orange-emitting CIS/ZnS QD can effectively contribute to the spectral extension of white light by supplementing the red spectral deficiency.

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