Core/shell/shell of CdSe/CdTe/CdS QDs were prepared by chemical reaction and used to fabricate hybrid quantum organic light emitting devices (QDOLEDs). QDOLEDs were made-up using layers of ITO/PEDOT: PMMA/QDs/Alq3and ITO/PEDOT: PMMA/QDs/Alq3/TPBi devices which prepared by phase segregation method. The hybrid white light emitting devices consists, of four-layers deposited successively on the ITO glass substrate; the first layer was of Poly(3,4-ethylenedioxythiophene) (PEDOT) polymer mixed with polymethyl methacrylate (PMMA) polymers. The second layer was QDs and the third layer was tris (8-hydroxyquinoline) aluminium (Alq3) while the fourth layer was 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL)The results of the optical properties show that the prepared QDs were nanocrystalline with defects formation. The produced white light has suitable efficiency by confinement effect which creates the energy gap larger, so that the aim of the light sites are toward the center of white light color.The quantum dots organic light emitting devices (QDOLEDs) were characterized by electroluminescence (EL) at room temperature. Current-voltage (I-V) characteristics indicate that the output current is good compared to the few voltages ( 4-6 V) used which gives acceptable results to get a generation of white light. The emissions affecting this white luminescence were detected depending on the chromaticity coordinates (CIE 1931). The correlated color temperature (CCT) was found to be about 6300 and 5290 K. Fabrication of QDLEDs from semiconductors material (CdSe/CdTe/CdS core/shell/shell QDs) with hole injection organic polymer (PEDOT) and electron injection from organic polymer molecules (TPBi) was successful in white light production.
White organic light-emitting devices with CdSe/ZnS quantum dots as a red emitter
