2013 Volume E96.C Issue 3 Pages 365-368
A self-assembled monolayer having a benzophenone unit as a photoreactive terminal group (BP-SAM) was prepared on an indium-tin oxide (ITO) electrode, on which a hole-transport layer of a phenoxazine-dioctylfluorene copolymer (H5) was spin-coated and irradiated with UV light. After washing the physisorbed H5 molecules, contact angle measurement and ellipsometry showed that the H5 molecules can be tethered to the ITO surface via the BP-SAM. Organic light-emitting diodes (OLEDs) were prepared in the structure of ITO/H5 hole transport layer/tris(8-hydroxyquinolato) aluminum/bathocuproin/LiF/Al electrode with and without the BP-SAM layer on the surface of ITO. The device with the BP-SAM showed higher current density and higher luminance due to the improvement of contact at the ITO/H5 interface by forming covalent bonds via the BP-SAM.
