Sunlight-operable light converting smart windows for fertilizer-free plant growth enhancement

The development of a smart sunlight window to promote plant growth without the need for fertilizer is of considerable interest in both materials science and biology. In particular, green light is considered as an inefficient wavelength in the solar spectrum for photosynthesis. In contrast, blue and far-red and near-infrared photons are preferable for plant growth. Here, we report on a smart window containing SrAl12O19: Ti3+ nanoparticles that are transparent in blue region of the solar spectrum but can selectively convert the less favorable green light to the most useful far-red and near-infrared light with respect to photosynthesis. When cultivated beneath such a smart window, plants, such as a garlic bolt and oxalis demonstrate remarkably improved longitudinal and lateral growth under direct outdoor sunlight or green and white LED room light. This method offers a simple way to maximize the use of solar energy for more effective plant cultivation without the need for fertilizer. In addition, such operable light converting nanoparticles may also lead to a wide variety of applications in the fields of biophotonics and photonics.