NOVELTY - A photovoltaic device comprises an optical system for enhanced light harvesting with a transparent layer of dielectric material having on one side an array of micro-lenses (4) and on the opposite side a metal reflective film (8) with an array of openings (6); first photovoltaic cell system (16) for the exploitation of direct sunlight located in the opposite hemi-space of the micro-lenses array; and a second photovoltaic cell system (30) for the exploitation of diffuse sunlight, located in the same hemi-space containing the micro-lenses array with respect to the plane of the openings array.    USE - A photovoltaic device.    ADVANTAGE - The device allows to exploit independently direct light and diffuse light, and has enhanced optical absorption and efficiency.    DETAILED DESCRIPTION - A photovoltaic device comprises an optical system for enhanced light harvesting with a transparent layer of dielectric material having on one side an array of micro-lenses (4) and on the opposite side a metal reflective film (8) with an array of openings (6). The micro-lenses focus direct sunlight impinging on it through the openings, thus separating direct sunlight and diffuse sunlight. The photovoltaic device includes first photovoltaic cell system (16) for the exploitation of the direct sunlight located in the opposite hemi-space of the micro-lenses array with respect to the plane of the openings array, and a second photovoltaic cell system (30) for the exploitation of diffuse sunlight, located in the same hemi-space containing the micro-lenses array with respect to the plane of the openings array. The first photovoltaic cell system is connected by a layer of a transparent dielectric material (18), which comprises elastomeric material, to the assembly of micro-lenses and openings array. The energy gap for the optical transitions in the active layers of both the first and second photovoltaic cell is 0.8-2.5eV. An INDEPENDENT CLAIM is included for the construction of photovoltaic device.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the photovoltaic device and possible ray paths of both direct and diffuse sunlight.    Micro-lenses (4)    Openings (6)    Metal reflective film (8)    First photovoltaic cell system (16)    Dielectric material (18)    Second photovoltaic cell system (30)