A prepreg composition includes a plurality of core/shell quantum dots that exhibit an increase in detectable luminescence when the prepreg composition has been exposed to an amount of UV radiation that would render the prepreg composition unsuitable for use in fabricating composite structures, thereby greatly simplifying detection of compromised prepreg materials that for example, may have been inadvertently and undesirably exposed to UV radiation during storage or handling. A method of manufacturing a prepreg composition includes forming a bed of fibers, contacting the fiber bed with a resin matrix, and disposing a plurality of core/shell quantum dots on or in the resin matrix.