NOVELTY - A luminescent solar concentrator device (1) comprises a receiving surface (11); a photoluminescent material (13) having a spectral content that is different from the absorbed solar radiation; a transmission surface (12) of the light radiation (L2) emitted by the photoluminescent material; and spectral and spatial filtering means (14, 15) adapted to select the spectral content of the light radiation (L2) emitted by the photoluminescent material.    USE - The luminescent solar concentrator device is used in a photovoltaic conversion apparatus (claimed).    ADVANTAGE - The luminescent solar concentrator devices allow an increase in the light power density received by the photovoltaic cells, and allow improvement of photovoltaic conversion efficiency. These devices are easy to produce at industrial level and are economically competitive with regard to installation and operating costs.    DETAILED DESCRIPTION - A luminescent solar concentrator device (1) comprises a receiving surface (11) adapted to receive the solar radiation (L1); a photoluminescent material (13), adapted to absorb the solar radiation and to emit a light radiation (L2) having a spectral content that is different from the absorbed solar radiation, with a net optical gain that is positive or zero; a transmission surface (12) of the light radiation (L2) emitted by the photoluminescent material, the transmission surface being optically associable with at least one photovoltaic cell (2); and spectral and spatial filtering means (14, 15) adapted to select the spectral content of the light radiation (L2) emitted by the photoluminescent material, the filtering means inducing the light radiation (L2) emitted by the photoluminescent material to propagate along a predefined main direction (Z). INDEPENDENT CLAIMS are:    (1) a photovoltaic conversion apparatus comprising at least one photovoltaic cell (2) and a luminescent solar concentrator device (1), operatively associated with the at least one photovoltaic cell; and    (2) an electrical power production system or a lighting system or a window or a building cladding panel comprising a photovoltaic conversion apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a concentrator device.    Luminescent solar concentrator device (1)    Photovoltaic cell (2)    Receiving surface (11)    Transmission surface (12)    Photoluminescent material (13)    Spatial filtering means (14, 15)    Solar radiation (L1)    Light radiation (L2)    Main direction (Z)