Effects of Indium-Tin-Oxide Surface Treatment on Organic Light-Emitting Diodes

Effects of mechanically polished and annealed ITO substrates on tris-(8-hydroxyquinoline)aluminium (Alq3)-based light-emitting diodes were studied. The roughness and O content at the ITO surface were reduced after mechanical polishing. Organic light-emitting diodes (OLEDs) fabricated on polished ITO surfaces showed ten fold better electroluminescence and current injection than OLEDs fabricated on as-received ITO surfaces, due to the increase of the smooth contact area between the ITO surface and the organic layer. The ITO substrate annealed at 300 C did not show much enhancement of electroluminescence, even though it showed high current injection at low voltage. Therefore, mechanical polishing is an effective treatment for enhancing the performance of OLEDs. 14 refs.