The a-Si:H p-i-n photovoltaic cells photosensitized with an organic layer of 5,10,15,20-tetra (4-pyrydil) 21H,23H porphine (TPyP) have been prepared. The action spectrum of these cells was extended by approximately 30 nm to longer wavelengths, with respect to non-sensitized cells. The presence of the organic layer gives some modifications in the electrical and photovoltaic behavior of the cells, that is why an analysis of dark current-voltage characteristics of the cells at room temperature, is also presented. (C) 2000 Elsevier Science B.V. All rights reserved.