光电子快报(英文版), 2018, 14 (4): 262, Published Online: Apr. 16, 2019
Effects of organic acids modified ITO anodes on lumi-nescent properties and stability of OLED devices
Abstract
In this paper, p-chlorophenylacetic acid and p-fluorophenylacetic acid were applied to modify the indium tin oxide (ITO) electrodes. The surface work functions of unmodified ITO, p-chlorophenylacetic acid modified ITO (Cl-ITO) and p-fluorophenylacetic acid modified ITO (F-ITO) are 5.0 eV, 5.26 eV and 5.14 eV, respectively, and the water contact angles are 7.3°, 59.1° and 46.5°, respectively. The increase of the work function makes the hole injection ability of the devices im-proved, which is proved by the hole transport devices. The self-assembly (SAM) layers transfer hydrophilic ITO to hydro-phobic ITO, which makes ITO more compatible with the hydrophobic organic layers, making the organic film more stable during the operation. After modification, the organic light emitting diodes (OLEDs), SAM-modified ITO/NPB/Alq3/LiF/Al, with better performance and stability were fabricated. Especially, the OLED with Cl-ITO (Cl-OLED) has a maximum lumi-nance of 22 428 cd/m2 (improved by 32.9%) and a half-lifetime of 46 h. Our results suggest that employing organic acids to modify ITO surface can enhance the stability and the luminescent properties of OLED devices.
HU Jun-tao, YE Kang-li, HUANG Yang, WANG Peng, XU Kai, WANG Xiang-hua. Effects of organic acids modified ITO anodes on lumi-nescent properties and stability of OLED devices[J]. 光电子快报(英文版), 2018, 14(4): 262.