A 200 nm x 2 mm array of organic light-emitting diodes and their anisotropic electroluminescence

We demonstrated the fabrication of a 200 nmX2 mm array of organic light-emi tting diodes (OLEDs) on a glass substrate. The photolithographic technique using an optical phase shift mask allowed us to construct a super-fine reso lution patterning of OLEDs. A single organic electroluminescent (EL) layer composed of an inert poly(methylmethacrylate) polymer binder and tetrapheny lbendidine and tris(8-quinolinol) aluminum molecules was fabricated on a fi ne-resolution photoresist patterning by a spin coating method. The lines an d spaces of the photoresist patterning were 200 nm. The emitting area was w ell confined by the regular array of residual photoresist resin walls. Fina lly, a MgAg cathode layer was uniformly deposited on the organic layer. We observed anisotropic EL spectra between the directions perpendicular and pa rallel to the patterning of OLED arrays. Furthermore, we observed a large d ifference of EL intensities between them. We assume that the anisotropic EL characteristics are caused by the confinement effect of photons inside the submicrometer-sized OLED array. (C) 1999 American Institute of Physics. [S 0003-6951(99)02709-6].