GRAPHENE-BASED PHOTOVOLTAIC DEVICE

A photovoltaic device and a method for preparing same are described. The photovoltaic device comprises at least one pair of electrodes, wherein each member of the at least one pair of electrodes having a different working function than the other member of that pair; and one or more layers of graphene located between the two electrodes, wherein the one or more layers made of graphene have a lower working function than a working function of one member of the at least one pair of electrodes, and a higher working function than a working function of the other member of the at least one pair of electrodes, thereby allowing generation of an electric field across the photovoltaic device without applying any external voltage to the electrodes, in response to solar radiation impinging the device. Optionally, one or both electrodes have a coating of a different buffering material than the other.