As a fundamental electrostatic limit, the space charge limit (SCL) for photocurrent is a universal feature and of paramount importance in organic semiconductors with unbalanced electron/hole mobility and high exciton generation. Here, we first demonstrate a new concept of plasmon-electrical effect to manipulate the electrical properties (photocarrier generation, recombination, transport, and collection) of semiconductor devices with the help of plasmonically induced light redistribution. With careful incorporation of metal nanostructure in organic photoactive layer, we report abnormally redistributed holes by the plasmon-electrical effect. Despite of the typically low mobility of holes, we shorten hopping path of low mobility holes to reach the anode and break the SCL with detailed multiphysics explanations. We will also introduce to a new plasmonic solar cell architecture to simultaneously achieve plasmon-optical and plasmon-electrical effects. The plasmon-optical effects are that (1) for the first time asymmetric modes of the metal nanostructures are excited to achieve a broadband enhancement of OSC absorption, and (2) the optical-power distribution is relocated that the optical power in carrier transport layer (which otherwise will be waste as the role of carrier transport layer is not for photon-absorption induced carrier generation) would transfer to active layer and contribute to the improvement of active layer absorption. We experimentally obtain high-performance plasmonic organic solar cells with PCE reaching 10.5%.
© 2016 Optical Society of AmericaPDF Article