Tokyo Tech Develops Solid Film That Converts Visible Light to UV for 100 Hours
Updated
Updated · Chemical Industry Digest · Jun 25
Tokyo Tech Develops Solid Film That Converts Visible Light to UV for 100 Hours
1 articles · Updated · Chemical Industry Digest · Jun 25
Summary
Tokyo Institute of Technology researchers built a solid thin film that upconverts visible light into ultraviolet light and kept it performing in air for more than 100 hours.
Only about 4% of sunlight at Earth’s surface is UV, and earlier upconversion systems usually used liquids that degraded in air, needed oxygen-free sealing, and struggled under natural sunlight.
The new material works at light intensities below natural sunlight, pairing a low excitation threshold with high conversion efficiency to generate UV even under weak visible light.
Using a melt-and-cool manufacturing process, the team made a reproducible film that cured UV-sensitive resin under simulated visible-only sunlight, pointing to uses in photocatalysis, hydrogen production, sterilization and industrial chemistry.
Solid-state materials can now convert visible light into higher-energy ultraviolet (UV) light, marking a major scientific breakthrough. This process, called photon upconversion, is much harder in solids than in liquids because it requires both high fluorescence efficiency and fast movement of energy between molecules. Achieving this means carefully controlling how light-absorbing molecules interact and preventing energy loss as heat. Recent advances have overcome these hurdles, leading to robust systems that efficiently upconvert light using triplet–triplet annihilation. These innovations open the door to practical applications, such as solar energy, purification, and advanced manufacturing, all powered by ordinary sunlight.