White Hybrid Light-Emitting Devices Based on the Emission of Thermal Annealed Ternary CdSe/ZnS Quantum Dots

We report on a white hybrid light-emitting device employing a mixture of ternary CdSe/ZnS quantum dots (QDs) as an emitting layer (EML) and a small molecular material tris(8-hydroxyquinoline) aluminum (Alq₃) as an electron-transporting layer. The film morphology of the spin-coated mixture of QDs is strongly improved via thermal annealing, and therefore a close-packed QD-EML is realized between organic charge-transporting layers. As a result, compared to the device with an unannealed QD-EML, the emission of Alq₃ is deeply suppressed. In addition, a maximum luminance of more than 1000 cd/m² and a maximum luminous efficiency of 2.2 cd/A are achieved.