Photo-induced Charge Transfer in Organic Semiconductor Nano-crystal Films: Kelvin-Probe and Transient Studies

We study the photo-induced charge transfer processes in organic nano-crystals, between electron donor and acceptor, to pave the way for employing organic nano-crystals materials for photo-voltaic relevant applications. We produced nano-crystals of sizes of sub-micron to microns of perylenediimides (PDIs) and Copper Phthalocyanine (CuPc), created their interfaces in three different forms, and studied the charge transfer phenomena with kelvin-probe force microscopy under laser or white light excitation. In addition, we studied the materials with femto-second transient absorption and photo-luminescence. This provides us fruitful information for understanding factors akin to photo-voltaic voltage under open-circuit condition.