Abstract: The invention provides luminescent solar concentrator (LSC) exhibiting high efficiency, and durable fluorescence properties, comprising at least one plate having two major surfaces and a plurality of edges having solar cells attached thereto, the plate comprising a substrate selected from the group consisting of glass and plastic and being provided with a composite inorganic-organic sol-gel based matrix film deposited on at least one major surface thereof, wherein the film is doped with at least one luminescent dye and the concentrator comprises at least three luminescent dyes of substantially different absorption ranges and wherein the film has a thickness of at least 10 ?m.