Ga-doped TiZnO transparent conductive oxide used as an alternative anode in blue, green, and red phosphorescent OLEDs

Abstract

X-ray diffraction was used to study the optoelectronic characteristics of Ga-doped TiZnO (GTZO) thin film and revealed increased crystallinity with annealing temperatures ranging from as-grown to 450 °C. The low thin film resistivity of 6.1 × 10⁻⁴ Ω cm and the average high optical transmittance of 93% in the wavelength range between 350 and 800 nm make GTZO an alternative candidate for application in organic light-emitting diodes (OLEDs). Both GTZO and indium-tin-oxide (ITO) anodes are employed for the successful fabrication of blue, green, and red phosphorescent OLEDs. The similar device electrical characteristics observed could be interpreted as evidence of the effectiveness of doping Ga in TiZnO. The simplified tri-layer blue, green, and red phosphorescent OLEDs demonstrated high performance with respective maximum efficiencies of 19.0%, 14.5%, and 9.1%, representing an improvement over ITO-based OLEDs. Furthermore, the OLEDs with the GTZO anode exhibited superior performance at higher current densities, demonstrating high potential for OLED display and lighting applications.