Bifunctional photovoltaic and electroluminescent devices using a starburst amine as an electron donor and hole-transporting material

Photovoltaic (PV) devices, using ${\text{4,4}}^{\prime }{\text{,4}}^{″}$ -tris(2-methylphenylphenylamino)triphenylamine (m-MTDATA) as an electron donor and tris-(8-hydroxyquinoline) aluminum (Alq) as an electron acceptor, were fabricated. The relationship between photocurrent generation, exciplex formation, and device structure was explored. PV performance was significantly enhanced by inserting a thin mixed layer (5 nm) of m-MTDATA and Alq between the two organic layers of the original m-MTDATA/Alq bilayer device. Both the bilayer and trilayer devices showed PV and electroluminescent (EL) properties, suggesting their potential use as multifunction devices. It was also shown that strong EL emission from exciplex might be used as an indicator of efficient exciton dissociation during the reverse PV process.