Abstract: ITO anode surfaces are polished with Al2O3.Machine polishing is replaced with an ultrasonic process,which is easier to control to obtain a better ITO anode surface.ITO-coated glass substrates (ITO thickness is 50±10nm,sheet resistance is 40Ω/□) are put into different water-graded Al2O3 polishing solutions with different Al2O3 granularities.Then devices are fabricated with a traditional double-layer structure.The performance of the organic light-emitting diodes (OLEDs) based on the indium tin oxide (ITO) anodes processed ultrasonically in Al2O3 polishing solution is improved.By optimizing the Al2O3 granularity to 0.6μm and the ultrasonic processing time to 10min,the drive voltage falls from 9 to 6V at 100cd/m2 compared with the control device,which underwent no treatment.The luminance of the device is over three times that of the control device,reaching 25880cd/m2 at 15V.The luminous efficiency is 3.82cd/A,which is the best of all the devices.As a result,with an Al2O3 granularity of 0.6μm and ultrasonic processing time of 10min,the electroluminescence performance of the ITO-treated device is improved.The solution-treated sample shows a much smoother surface than the non-treated one,which enhances the hole injection,leading to improved device performance.

Key words: organic light-emitting device, indium tin oxide anode, polishing