High efficiency ultraviolet photovoltaic cells based on ZnO-C-60 core-shell QDs with organic-inorganic multilayer structure

We report on the successful conjugation of C-60 molecules on the surface of ZnO quantum dots (QDs) and their application in multilayer structured ultraviolet (UV) photovoltaic (PV) devices. In situ growth of C-60 on the surface of ZnO QDs with a core-shell structure was realized via a mild solution-process method, which resulted in an improvement in photo-induced charge separation and transport of carriers to the collecting electrodes in a fabricated device. The conjugation of the C-60 with ZnO QDs leads to a PL quenching of about 99.8%, which can be attributed to an efficient transfer of photo-induced electrons from the ZnO QDs to the C-60 through a Zn-O-C chemical bonding. UV PV cells with ZnO-C-60 core-shell QDs as an active layer and fabricated through an all layer simple chemical method exhibit high power conversion efficiency as much as about 3.02%.