We report a theoretical study about the performances of graphene on semiconductor Schottky barrier solar cells with the aim to show the potentiality of this kind of device. The simulations are carried by a generalized equivalent circuit model, where the circuital parameters are strictly dependent on the physical properties of the graphene and semiconductor which form the Schottky junction. We have realized graphene samples and characterized them by optical and atomic force microscopy, and Raman spectroscopy. Capacitance-voltage measurements have been made on some "ad hoc" graphene based devices in order to obtain graphene workfunction, a very essential physical parameter. The estimated value is compatible with four layer graphene. This result is in agreement with the morphological characterizations of our material. (C) 2012 Elsevier B.V. All rights reserved.