Increasing greenhouse production by spectral-shifting and unidirectional light-extracting photonics

Improving photosynthesis and light capture increases crop yield and paves a sustainable way to meet the growing global food demand. Here we introduce a spectral-shifting microphotonic thin film as a greenhouse envelope that can be scalably manufactured for augmented photosynthesis. By breaking the intrinsic propagation symmetry of light, the photonic microstructures can extract 89% of the internally generated light and deliver most of that in one direction towards photosynthetic organisms. The microphotonic film augments lettuce production by more than 20% in both indoor facilities with electric lighting and in a greenhouse with natural sunlight, offering the possibility of increasing crop production efficiency in controlled environments. A unidirectional light-extracting fluorescent film was designed for passive augmentation of photosynthesis and biomass production for leafy green lettuces grown indoors and in greenhouse facilities. The batch-processed films have a total light extraction efficiency of 89%, with a majority of the converted light directed towards lettuce crops. This film demonstrates application potential in greenhouses and other protected environments to increase crop production efficiency.