EurekAlert December 4, 2020
To directly convert visible light with wavelengths longer than 400 nm into higher-energy ultraviolet light researchers in Japan focused on triplet-triplet annihilation where triplets are formed on molecules following absorption of visible light. These “donor” molecules then give their triplets to “acceptor” molecules that can combine two triplets to create a single, higher-energy state that is released as ultraviolet light. They developed an acceptor molecule TIPS-naphthalene that has a high triplet-triplet-annihilation efficiency and a low enough triplet energy to easily accept triplets from a molecule called Ir(C6)2(acac). The combination of TIPS-naphthalene and Ir(C6)2(acac) successfully achieved the highest upconversion efficiency of 20.5% under high-intensity light. The research has applications in high-energy rays to power photocatalysts that enable a variety of useful reactions from producing hydrogen for use in fuel-cell vehicles to purifying indoor environments…read more. TECHNICAL ARTICLE