Apparatus and methods to enhance light intensity within useful red to near-infrared spectral ranges, using direct or indirect sunlight, or from other ambient white light, are described. The disclosed devices provide high quantum yield photoluminescent ambient light spectrum conversion to increase the supplied energy primarily in the 590 nm-850 nm spectral range. These devices also pass much of the incident light in the spectral range in which the device's photoluminescent materials emit light, thereby greatly increasing the effective intensity of light available in the targeted 590-850 nm wavelength range. The ambient light conversion devices of the disclosure may be incorporated in apparel, bandage-like patches, converting reflectors, large area converters, awnings, window covers, and other articles, materials, and products. The converted light may be used in therapeutic treatments, horticultural and biotechnological applications, and other applications in which the converted light outputs of the present disclosure are beneficial.
