Solar spectrum modification by luminescent agriculture films for enhanced light use efficiency in greenhouse plant trials

Modifying the spectral quality of light for crops grown in controlled environments has had a large influence on plant development in terms of plant morphology and photosynthetic light use efficiency (LUE). Most research focused on light quality has been conducted with LED lamps in growth chambers, and these results are limited to applications such as vertical farming or supplemental lighting for greenhouses in low natural-light conditions. In this work, a new luminescent film technology has been developed that passively modifies the solar spectrum to reduce blue wavelengths and enhances the red wavelengths through a luminescent photoconversion process. This process utilizes a nanotechnology called quantum dots to offer a sustainable option for enhancing light quality in greenhouse applications that does not require electricity and instead relies on the power of the sun. Greenhouse plant growth trials were conducted under luminescent agriculture CuInS2 quantum dot films that were installed over crops to compare to adjacent crops grown under a clear control film without QDs. Crop production was improved for lettuce under both QD treatments. The O625 QD film treatment showed increases in fresh mass (FM) ranging from +19-+21%, dry mass (DM) of (+16-+31%), and LUE (+14%) compared to the control. The R650 QD film showed improvements in FM ranging from +13 to +25%, DM from +20 to +30%, and LUE ranging from +22 to +39%. For one lettuce trial with low DLI (11.9 mol m^-2 day^-1), no improvements were observed from the QD treatment, potentially indicating a minimum light intensity needed before spectrum modification can benefit lettuce growth in greenhouses.