Incorporation of quantum dots within greenhouse films has the potential to enhance local food production with a reduced carbon footprint, without compromising yield or quality. Silicon quantum dots in particular hold advantages over other photoluminescent nanoparticles in that they have low toxicity and are highly tunable. The down-shifting of photons observed under silicon quantum dot films can enhance vegetative productivity of plant commodities, but due to a relatively low photon emission efficiency of the films, the transmitted light to crop canopies below is reduced. A growth model has been used to predict the performance of lettuce grown under a silicon quantum dot spectrum, but no studies have been conducted to validate these predictions. Our study aimed to evaluate the yield and physiological performance of Lactuca sativa cv. ‘Rex’ grown in controlled environment growth chambers fit with tunable 11-channel LEDs which were used to match the color fraction of a solar spectrum transmitted through glass greenhouse glazing or a solar spectrum transmitted through a silicon quantum dot film. Light intensity levels of 500 and 350 µmol m−2 s−1 were also tested to simulate the expected 33% loss of light transmission through the silicon quantum dot film at a density of 5 wt%. The spectrum and light intensity treatments were tested in a factorial design for a total of four treatments, with each treatment replicated five times. Fresh biomass results from the growth chambers showed that growth model predictions underestimate the performance of ‘Rex’ under the mock silicon quantum dot spectrum. The elimination of UV-A photons and enrichment of red and far red photons in the mock silicon quantum dot treatment increased leaf area and growth at their respective light intensities compared to the mock solar spectrum; however, the yield of the 350 µmol m−2 s−1 mock silicon quantum dot spectrum did not surpass that of the 500 µmol m−2 s−1 mock solar spectrum. This research highlights the importance of coupling solar cells with silicon quantum dot films to increase their economic feasibility and further illuminates the effects of down-shifted spectra on lettuce physiology.
