Control of metal oxide nanoparticles as a charge transport layers for solution-processed OLEDs and QLEDs

Abstract

In this thesis, nickel oxide and znic oxide nanoparticles which has used in multilayer optoelectronic device with excellent optical and electrical properties are mainly discussed. In the case of nickel oxide, it was co-doped with copper ions having different oxidation numbers of copper (I) and copper (II). The enhancement of conduction / injection was confirmed by electrical analysis and it was determined that the improvement of electrical properties were result of chemical composition change by chemical analysis. The co-doped nickel oxide film adjusted OLED showed 1.5 times increased current efficiency compared to the conventional nickel oxide device by improving the charge balance. Zinc oxide was hybrided with two multifunctional polymers. Optical and chemical analysis indicated the surface defect passivation and observed the shift in injection barrier due to the interface dipole effect. The vinyl and methyl backbones of the polymers improved the charge balance by suppressing the excessive electron current in the Cd-based QLED and QLED showed the current efficiency of 34.7 Cd/A.