Effect of structure ordering on charge carrier mobilities in green-emitting poly(phenylene vinylene)s

Abstract

Charge transport behaviors and performances of electroluminescent (EL) devices of the two greenemitting poly(phenylene vinylene)s, the homopolymer of 2-[3′-(3,7-dimethyloctyloxy)phenylene]p-phenylene-vinylene and the copolymer of 50% by mole 2-[4′-(3,7-dimethyloctyloxy)phenylene]p-phenylene-vinylene and 50% 2-[3′-(3,7-dimethyloctyloxy)phenylene]-p-phenylene-vinylene are investigated. The former is found to have more ordered chain alignment than the latter. Such ordered alignment leads to significant increases of the mobilities of charge carriers, especially for that of an electron, which is promoted to a level equivalent to that of a hole. The balance of electron and hole mobility could be the reason for its high brightness (100 000 cd/m2) and efficiency (12 cd/A) of the EL device.