UCLA scientists have discovered a way to reconcile the conflict between solar farms and conventional agriculture by integrating semi-transparent solar cells onto greenhouse roofs, which have the added benefit of promoting plant growth. The team’s organic solar cells proved to be the perfect candidate for this concept due to their transparency and flexibility, but were limited by their quick degradation under sunlight. The researchers added a protective layer of L-glutathione to prevent the cells from breaking down, and found that they retained 84% of their original efficiency after 1,000 hours of continuous use.
Improving Crop Yields
The team conducted tests using wheat, mung beans, and broccoli grown in two greenhouses; one with a clear glass roof with segments of inorganic solar cells and another with a roof entirely consisting of semi-transparent organic solar cells. The organic cells allowed 21.5% of visible light to pass through, with a power conversion efficiency of 13.5%. To their surprise, the plants grown under the organic cells outperformed those in the traditional greenhouse. The researchers discovered that plants do not need as much sunlight as previously thought, and that excessive sun exposure can actually be harmful to plant growth, particularly in regions with abundant sunlight, such as California. The L-glutathione layer was also found to block ultraviolet rays and infrared rays, which can damage plants and overheat the greenhouse.
Commercializing the Concept
The team’s discovery has promising implications for the future of sustainable agriculture and renewable energy. The integration of solar cells onto greenhouse roofs not only mitigates the conflict between solar farms and agriculture, but also promotes plant growth and efficiency. The team has set up a startup to scale up production of these organic solar cells commercially. The organic cells have the added advantage of being less expensive and less resource-intensive to produce than traditional inorganic solar cells, and their flexibility makes them easier to install on curved surfaces. The team believes that their technology can be implemented in various forms, from large-scale commercial greenhouses to individual garden structures. As Yepin Zhao, the lead author of the study, said, “We’re hoping our technology can play a role in meeting rising food demands and increasing renewable energy use.”
