The invention concerns a photoactive nanocomposite (3) comprising at least one donor-acceptor couple of semiconductor elements. One of the elements is made of doped nanowires (7) with sp3 structure, and the other of the elements is an organic compound (8). The elements are supported by a device substrate (1). The invention also concerns a production method. According to a first embodiment, after their growth, the nanowires (7) are retrieved, functionalised and solubilised in the organic component (8). The mixture is deposited by coating on a device substrate. According to a second embodiment, the nanowires (7) are formed on a growth substrate (5) which is also the device substrate. The organic component (8) is combined with the nanowires (7) so as to form an active layer (3). Such a photoactive nanocomposite (3) allows production of a photovoltaic cell.