Organic light-emitting devices patterned by screen-printing

We have demonstrated a patterned organic light-emitting device fabricated by screen-printing on the basis of the doped hole-transport layer (DHTL) which is our novel concept. The DHTL, which consisted of a polymeric compound of N,N'-diphenyl-N,N'-bis(3-methylphenyl)- 1,1'-biphenyl-4,4'-diamine (P-TPD) as a hole-transport material and tris (4-bromophenyl) aminium hexachloroantimonate (TBAHA) as an electron-accepting dopant, was patterned by screen-printing. The luminous area of the device was restricted to the DHTL-printed area. The device was operated at approximately 5 V, and a luminance of 4800 cd/m(2) was obtained at a current density of 150 mA/cm(2). The appropriate concentration of P-TPD was 80 g/l in dichlorobenzene, at which a smooth and pinhole-less layer was obtained with a thickness of 0.5 mu m. The suitable concentration of TBAHA in P-TPD was approximately 8 wt%.