The effects of chemical treatment on ITO properties and performance of OLED devices

摘要

In this work, chemical treatment was performed on the surfaces of two types of indium tin oxides (ITOs) with different physical properties. The effects of the chemical treatment on the physical parameters of the ITOs, and on the efficiency of the organic light emitting diodes (OLEDs) fabricated on the ITOs, were then examined. The ITO substrates were characterized via X-ray diffraction, atomic force microscopy, optical absorption, and electrical resistance measurement. The results showed that the chemical treatment exerted no significant changes on the structure and transparency of the wavelength of the light emitted from Alq_3; however, the treatment improved the morphology and resistance of the ITOs examined. To serve the research purpose, the ITOs were first characterized, and then, the OLEDs were fabricated so that they would have a structure of Glass/ITO/PEDOT:PSS/ Alq_3/Al. The OLEDs were characterized current density, resistance, power, and irradiance as a function of the voltages. The results of the study showed decreases in the turn-on voltage (from 5.5 to 4 V for one of the OLEDs and 7 to 6 V for the other), resistance and power (for one of the ITOs), and irradiance (for one of the ITOs) due to the chemical treatment.