A series of organic photovoltaic (PV) cells in which the electron acceptor and donor are gadolinium (dibenzoylmethanato)3(bathophenanthroline) and N,N′-diphenyl-N,N′bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine , respectively, were fabricated. Although TPD acts as an active layer in the bilayered cells, insertion of a Gd-complex film between TPD and the alloy cathode is necessary for efficient carrier photogeneration. Open-circuit voltage of 3.2 V is obtained due to efficient exciton dissociation near the interface between (Gd(DBM)3bath) and TPD. By incorporating an ultrathin mixed layer of Gd-complex and TPD, external quantum efficiency is improved significantly.It was found that photovoltaic performance of the devices has a common origin, exciplex formation, which results in broadband emission during both photoluminescent and the electroluminescent processes.
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