Photolithographic hole-transport layer derived from electrochemical deposition of oligo(5-vinyl-2-nitrobenzyl triphenylamine-4-carboxylate)

Electrochemically deposited layer (EDL) prepared from electropolymerization of oligo(5-vinyl-2-nitrobenzyl triphenylamine-4-carboxylate) on conductive indium tin oxide glass (ITO) showed photolithographic properties as well as good hole-injection and transport properties. Under the optimized conditions, the polymeric light-emitting device (PLED) of ITO/EDL/polyvinylcarbazole(PVK)-Ir(PPY)(3)[2-bihenylyl-5-(4'-tert-butylphenyi)oxadiazole] (PBD)/Ma-Ag had a turn-on voltage of 13.5 V (100 cd/m(2)) with a maximum brightness of 9100 cd/m(2) and the current efficiency of 10.3 cd/A. When the EDL was exposed to UV liight (365 nm) through a patterned photomask and developed in CH2Cl2, a positive image was obtained. After irradiation for 8 min through a band-pass filter (17 mW/cm(2)) by a Xeon lamp, the EDL became soluble and could be depleted completely in CH,Cl,. Patterned PLED device was also fabricated by this technique.