Plant growth acceleration using a transparent Eu-painted UV-to-red conversion film.

The stimulation of photosynthesis is a strategy for achieving sustainable plant production. Red light is useful for plant growth because it is absorbed by chlorophyll pigments, which initiate natural photosynthetic processes. Ultraviolet (UV)-to-red wavelength-converting materials are promising candidates for eco-friendly plant cultures that do not require electric power. In this study, transparent films equipped with a UV-to-red wavelength-converting luminophore, the Eu complex, were prepared on commercially available plastic films for plant growth experiments. The present Eu-based films absorb UV light and exhibit strong red luminescence under sunlight. Eu-painted films provide significant growth acceleration with size increment and biomass production for vegetal crops and trees in a northern region. The plants cultured with Eu-painted films had a 1.2-fold height and 1.4-fold total body biomass than those cultures without the Eu luminophores. The present film can promote the plant production in fields of agriculture and forestry.