Nitrogen- and sulfur-containing conjugated polymers as the hole-transporting materials

A series of novel nitrogen- and sulfur-containing conjugated polymers have been synthesized via an acid-induced self polycondensation of functional mo nomers with methyl sulfinyl group. They exhibit good solubility in common s olvents, such as CHCl3, THF, DMF, DMSO, et al; and thus show excellent film -forming properties. They are used as hole-transport layer (HTL) in two-lay er light-emitting diodes (ITO/polymer/Alq3/Mg:Ag). The typical turn-on volt age of these diodes is about 4 similar to 5V. The maximum brightness is abo ut 3440cd/m(2) at 20 V. The maximum efficiency is estimated to be 0.15 Im/W at 10V.