Investigation on tunable EL from ZnO QDs/SiO₂ hybrid devices

The ZnO QDs/SiO₂ composite materials, which were synthesized in different concentrations of SiO₂-ethanol solution, were fabricated into light-emitting devices by spin coating. With the increase of SiO₂ concentration, electroluminescence (EL) spectra of the devices are blue shift gradually. Experiments were designed and carried out to explore the mechanism of the spectrum-tunable EL with SiO₂. The EL spectra of the series of devices, which were fabricated with the mixtures of the ZnO QDs/SiO₂ sample and pure SiO₂ in different molar ratios, indicate that the spectrum-tunable EL performance is not related to the emission of SiO₂. The quantum size effect may be significant for the spectrum-tunable EL behavior, Gaussian multi-peak fitting for EL spectra showed that the increased ratio of green and orange-red emission with the increasing SiO₂ concentration results in the blue shift of EL spectra.