TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: In the luminescent solar collector, the luminescent sheet is also optically connected to a substrate that is transparent between 400 and 700 nm. The polymer material is comprised of a material containing poly (alkyl methacrylates), polycarbonate, fluorinated polymer or a derivative or combination. The fluorescent materials emit at least 50% of radiated photons with wavelengths between 600 and 690 nm. The percentage of solar photons absorbed by the fluorescent materials between 410 nm and 490 nm is less than a percentage of solar photons absorbed by the fluorescent materials between 500 and 600 nm, and where a percentage of solar photons absorbed by the fluorescent materials between 620 nm and 680 nm is less than a percentage of solar photons absorbed by the fluorescent materials between 500 and 600 nm. The concentration of the fluorescent materials in the polymer material, measured in wt.%, multiplied by the thickness of the luminescent sheet, measured in millimeters, is between 0.005 and 0.05. The photoactive surface of the light energy converter is mounted approximately parallel to a plane of the luminescent sheet. The back surface of the light energy converter is mounted on a supportive frame. The percentage of active area of the light energy converter to an active area of the luminescent sheet is between 5% and 35%. The light energy converter is composed of silicon, gallium arsenide, copper indium gallium selenide or cadmium telluride photovoltaic. The luminescent solar collector further comprises an additional transparent sheet positioned behind the light-energy converter for purposes of protection; a second luminescent sheet which contains a second fluorescent material which absorbs less than 50% of solar photons between 620 and 680 nm, and where the second luminescent sheet is optically coupled to the light energy converter; and additional single or multiple non-luminescent sheets which contain a light diffuser, an IR-absorber, a IR-reflector, or a combination. The backsheet material is textured to make the transmitted light diffuse. The ratio of red transmission between 620 and 680 nm to blue transmission between 410 nm and 490 nm is greater than 1. Moreover, it absorbs greater than 30% of the light in the far-red region between 700 nm and 900 nm.