Enhanced plant growth and harvestable yield through fluorescent copper-based composites

Improving crop productivity without increasing land, energy or chemical inputs is a critical challenge for sustainable agriculture, and spectral conversion materials that transform underutilized ultraviolet radiation into photosynthetically active radiation (PAR) offer a promising solution. Here, we report copper-based luminescent composites that enable wavelength-selective spectral reshaping and evaluate their physiological impact on Raphanus sativus grown under controlled greenhouse conditions. Three complementary materials were developed: melt-quenched glass composites incorporating the copper iodide clusters [Cu4I4(PPh3)4] and [Cu4I4(PPh2Et)4], and flexible cellulose acetate films embedded with copper-carbon nanoassemblies (Cu-CNAs), producing blue-green, yellow, and blue emissions, respectively, within the PAR window. Plant trials revealed clear wavelength dependent responses, with blue and blue-green emission accelerating early foliar expansion, while prolonged exposure to the yellow emitting [Cu4I4(PPh2Et)4] composite delivered the highest final biomass and significantly increased chlorophyll, carotenoid and ascorbic acid content, indicative of enhanced carbon assimilation and photoprotective metabolism. These results demonstrate that copper-based luminescent composites provide a scalable, low-cost and sustainable platform for spectral optimization in controlled environment agriculture, offering a practical materials driven strategy to improve both crop yield and nutritional quality.