Rubrene/fullerene heterostructures with a half-gap electroluminescence threshold and large photovoltage

Light and current generation functions from a rubrene/fullerene heterostructure are integrated into an efficient organic dual device (see figure). Electroluminescence, with the characteristic rubrene color, has a turn-on voltage less than 1 V. Solar-power conversion efficiency reaches 3% with a 5.3 mA cm(-2) short-circuit current density and almost 1 V open-circuit voltage under AM 1.5 illumination. The half-bandgap electroluminescence turn-on voltage is interpreted as an Auger fountain effect.