At the International Symposium on Photochromism (ISOP'2019 Paris) held at the Institut Pasteur in Paris, France from September 23 to September 27, Aoyama Gakuin University's Ayako Tokunaga won the Poster Award. Tokunaga is a first-year chemistry-course doctoral student at the Aoyama Gakuin University Graduate School of Science and Engineering.

ISOP'2019 Paris is an international event held once every three years for purposes of presenting the latest research results in the photochemical field of photochromism and sharing related information. Posters are presented over a 2-day period by 97 participants, which include researchers and students, after which 49 are selected for final evaluation and 4 receive Poster Awards.

Tokunaga presented her research through a poster titled "Red-Light Driven Photochromic Molecule by Using Triplet Fusion." Red light, near-infrared light and other low-energy light types have greater permeability in biotissue, organic materials and similar compared with ultraviolet light, and also cause less damage. Therefore, researchers utilize the color-change reactions that result from irradiation with red light and near-infrared light photochromic molecules(*1), and some hope to realize "molecular switches" by controlling the internal properties of cells, materials and so forth using light.

Tokunaga found that the mixed solution of a triplet energy donor molecule and a photochromic molecule having a triplet energy acceptor unit shows a photochromic reaction via triplet fusion(*2) upconversion even under low-energy red light irradiation.

In addition to exhibiting brilliant research results, Tokunaga's poster presentation was carried out extremely well and her overall responses and attitude during the question-and-answer session highly rated, earning her a 2019 Poster Award.

*1 Photochromic molecule: A molecule whose structure changes in response to light. This molecule type is capable of changing its color, molecular properties, etc. The high-speed photochromic molecules developed in the Jiro Abe Research Laboratory have properties not found in other photochromic molecules, enabling them to change their color, molecular properties and similar at higher speeds. Expected applications include sunglasses that take on their colored shading only when the user steps outside, real-time holograms, and other such innovations.

*2 Triplet fusion: A process the takes place between two molecules in an excited state known as a triplet state. The two molecules collide with one another, resulting in one of the molecules transferring its energy to the other, bringing the recipient molecule to a higher excited state. An "excited state" refers to a state achieved after a molecule in its ground state (stable state) receives energy in the form of light, heat or similar, thus putting it in an energized, unstable state.