Plants convert visible light to energy via a process called photosynthesis. In addition to visible light, sunlight also contains ultraviolet (UV) light. Researchers in this study aimed to provide plants with additional visible light to use in photosynthesis by employing a wavelength converting material (WCM) that can convert the UV light into red light. Researchers developed a WCM based on a europium complex and made a thin-film coating that can be applied to commercially available plastic sheets. Researchers not only showed that the film converts UV light to red light, but also that the film does not block any of the beneficial visible light from the sun. The film was then tested by comparing plant growth using sheets with and without the WCM coating. Trials were performed for both Swiss chard, a vegetal plant, and Japanese larch trees. In summer, when days are long and sun irradiation is strong, no significant difference was observed for Swiss chard when using the WCM films. In