Enhanced performance of organic electroluminescent diodes by UV–ozone treatment of molybdenum trioxide

The operating voltage is reduced and luminous efficiency is improved in the organic light-emitting diodes (OLEDs) with UV–ozone treatment of molybdenum trioxide (MoO3) anode buffer layer. The interface of indium tin oxide (ITO)/MoO3 was investigated by X-ray photoelectron spectroscopy. It was found that the binding energies of Mo 3d, O 1s, In 3d and C 1s were shifted to higher after UV–ozone treated MoO3. The enhanced properties are impervious to the UV–ozone treatment of ITO. Therefore, the improved performance can be attributed that the binding energies of Mo 3d, O 1s, In 3d and C 1s are changed to higher and also that the sheet resistance of ITO/MoO3 films is decreased after UV–ozone treated MoO3.

► The performance of OLED is improved by O3 treatment of molybdenum trioxide (MoO3).
► The enhanced performance can be due to the change of ITO/MoO3 sheet resistance.
► The improvement of performance is also due to oxidation by O3 treatment of MoO3.
► XPS shows the binding energy of Mo 3d after O3 treated MoO3 are shifted to higher.