Enhanced performance of organic light-emitting devices by atmospheric plasma treatment of indium tin oxide surfaces

Atmospheric plasma treatment of indium tin oxide (ITO) surfaces has been studied and demonstrated to be the most efficient method in improving the performance of vacuum-deposited double-layer organic light-emitting diode devices, among various plasma treatment methods including low-pressure Ar plasma and low-pressure ${\mathrm{O}}_{\mathrm{2}}$ plasma treatment. Although with a current–voltage characteristic close to low-pressure ${\mathrm{O}}_{\mathrm{2}}$ plasma treatment, the atmospheric plasma treatment exhibits a 40% increase of electroluminescence efficiency. X-ray photoelectron spectroscopy results show that the atmospheric plasma treatment increases the work function and reduces the carbon contamination of ITO surfaces. Our results suggest that atmospheric plasma treatment is a cheaper, more convenient, and more efficient method than low-pressure ${\mathrm{O}}_{\mathrm{2}}$ plasma treatment for improving device performance.