Charge injection at interfaces between molecularly doped polymer thin films

Charge injection between the active layers in organic semiconducting devices is a key determinant of device function. Accordingly, understanding the effect of intermixing between the layers at these interfaces is of fundamental importance. In this letter, via the use of the time-of-flight method, a comparison is made between the charge injection across discrete versus intermixed interfaces of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine and 1,1-bis((di-4-tolylamino)phenyl)-cyclohexane doped polycarbonate, semiconducting thin-film layers. No perturbation to the overall charge transport was observed with the discrete interface; however, in contrast the rate of charge transport was clearly reduced through the intermixed interface.