Characterization of Hybrid Composites of Nano YAG:Ce-CdSe/ZnS Quantum Dots and Conjugate Polymer Used for Solid State Lighting

摘要

White light was obtained by mixing blue light from emission of Indium Gallium Nitride (InGaN) chip and green-yellow-red light form the fluorescence of nano-Y3Al5O12:Ce (YAG:Ce), CdSe/ZnS quantum dots (QDs) and Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) polymer hybrid composite. The hybrid composite was coated on InGaN chip by way similar to slurry method. To achieve an efficient white light emitting diode (WLED) it is necessary to obtain a hybrid composite as homogeneous as possible and with excellent thickness uniformity. The used QDs have core-shell structure with thirteen ZnS monolayer. The properties of YAG:Ce, CdSe/ZnS QDs and MEH-PPV polymer hybrid composite prepared by slurry method were examined using photoluminescence. In this paper, the WLED fabricated by coating the hybrid composite was examined by PMS-50(PLUS) UV-VIS-near IR Spectrophotocolorimeter. The chromaticity of WLED depends on the thickness of the hybrid composite layer. The thickness of this layer could be easily controlled by slurry method. The luminous efficiency of WLED was 20.8 (lm/W) with a colour rendering index (CRI) of 75.8 at 200 mA. The WLED exhibited white light with a CIE coordinates of (0.30, 0.35).