Electroluminescence from organic/inorganic heterostructure device based on blends of PVK and water–sol CdSe nanocrystals

Organic/inorganic heterostructure devices were fabricated with polymer material poly(N-vinylcarbazole) (PVK) and CdSe nanocrystals synthesized in aqueous solution. Stable electroluminescence (EL) was obtained from the organic/inorganic heterostructure devices with different mass ratios of CdSe to PVK and under different applied voltages. With increasing applied voltages, the ratio of EL from CdSe nanocrystals to that from PVK decreased, and the color of the emission could be tuned from yellow to white. By changing the mass ratios of CdSe to PVK and the applied voltages, we obtained a pure white color from the heterostructure device with the CIE coordinates of (0.313, 0.336) for the mass ratio of CdSe:PVK = 9:1 at 24 V. The EL emission from the devices is mainly attributed to the incomplete energy transfer and carrier trapping directly on CdSe nanocrystals.