University of Colorado Boulder (CU Boulder) engineers have received a $2.45 million grant from the U.S. Department of Agriculture (USDA) to develop a scalable, cost-effective greenhouse material that splits sunlight into photosynthetically efficient light and repurposes inefficient IR light to aid in solar-driven water purification. The thin engineered material is applied directly to the surface of greenhouse panels. Assistant professor Ronggui Yang (left) and assistant professor Xiaobo Yin in a greenhouse on the University of Colorado Boulder campus. Courtesy of Glenn Asakawa/University of Colorado Boulder. “The new CU Boulder technology will take the form of a semitranslucent film that splits incoming light and converts the rays from less-desired green wavelengths into more desirable red wavelengths, thus increasing the amount of photosynthetically efficient light for the plant with no additional electricity consumption,” said professor Xiaobo Yin. “The near-infrared wavelengths can help clean brackish wastewater, allowing it to be recirculated in an advanced humidification-dehumidification interface and further reducing the greenhouse’s energy footprint,” said professor Ronggui Yang. Under normal conditions, plants use only around 50 percent of incoming sunlight for photosynthesis while the remaining half goes unused. The study will be led by researchers from CU Boulder’s Department of Mechanical Engineering in collaboration with Michigan State University’s Department of Horticulture. The innovation could help improve U.S. agricultural competitiveness and lead to new best practices for greenhouse systems in different climates, especially in arid regions with limited freshwater availability where crops cannot be grown profitably.