# Kyushu University Scientists Convert Visible Sunlight Into UV Light in 14-Year Breakthrough

*2026-06-27 14:02 UTC · Science · 2 min read*

> Kyushu University researchers developed a solid-state material that converts visible sunlight into UV light via triplet-triplet annihilation, achieving 60%+ quantum yield and 100-hour air stability.

Researchers at Kyushu University in Japan have developed the world's first solid-state material capable of converting ordinary visible sunlight into ultraviolet (UV) light at natural sunlight intensity. Published in Nature Communications on June 23, the study uses a process called triplet-triplet annihilation (TTA), where two visible light photons are combined to produce a single higher-energy UV photon. "What we do here is 'add together' the energy from two visible light photons to make one ultraviolet photon," explained Associate Professor Yoichi Sasaki.

The key material is dihydroindenoindenedene (DHI), an organic semiconductor modified with alkyl chains that prevent molecules from quenching each other's energy in the solid state. The result is a quantum yield above 60% and a conversion efficiency of 1.9% under actual outdoor sunlight — enough for practical real-world use. Crucially, the material maintains its performance for more than 100 hours in open air, setting a new benchmark for durability in this class of materials.

"This discovery is the culmination of over 14 years of our research and marks a major milestone," said Professor Emeritus Nobuo Kimizuka. Potential applications span indoor air purification, solar-driven photocatalysis, and low-intensity 3D printing — all powered by sunlight alone, with no electrical input. A patent application has already been filed for the technology.

## Sources

- [scitechdaily.com](https://scitechdaily.com/scientists-turn-ordinary-sunlight-into-uv-light-in-major-energy-breakthrough/)
- [nature.com](https://www.nature.com/articles/s41467-026-73898-0)

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TechTools News · https://techtools.cz/tools/news/article/1901-kyushu-university-scientists-convert-visible-sunlight-into-uv-light-in-14-year
Česká verze: https://techtools.cz/tools/news/clanek/1974-vedci-z-kjusu-prevadeji-viditelne-slunecni-svetlo-na-uv-zareni-po-14-letech