Molecular relay architecture facilitates accelerated photon upconversion for solar and healthcare applications
by Riko Seibo
Tokyo, Japan (SPX) Jun 16, 2025
A groundbreaking molecular design established by scholars at Kobe University boosts light upconversion by facilitating quicker intramolecular energy transfer. This breakthrough may lead to more effective solar energy solutions and improved medical diagnostics.
Photon upconversion, which involves the combination of two low-energy light particles into a single higher-energy particle, has potential for uses ranging from photovoltaics to precise therapies. Nonetheless, this approach typically relies on rare and inefficient molecular collisions with exact alignment. Researchers have been striving to enhance both the reliability and effectiveness of this operation.
Under the leadership of photoscientist KOBORI Yasuhiro, the Kobe group formulated a molecule that considerably elevates the probability of successful energy fusion occurrences. By positioning three anthracene molecules around a central boron atom, the team constructed a configuration where an excited state, or triplet exciton, can swiftly transfer among the anthracenes. This internal transfer enhances the effective interaction area and sustains energy levels, rendering the energy fusion—referred to as triplet-triplet annihilation—more feasible during molecular interactions.
“Our study elucidates how absorbed energy travels and transforms the molecule,” stated Kobori. “This insight can direct the development of more efficient upconverters.”
Published in Angewandte Chemie International Edition, the innovative molecular arrangement exhibited a 20% quicker rate of triplet fusion compared to earlier designs. The hopping velocity of the triplet exciton surpassed the typical duration of molecular collisions, enhancing the orientation match necessary for upconversion.
Furthermore, the researchers uncovered that luminescence efficiency can be modified by varying the viscosity of the medium. A more viscous setting diminishes both molecular interactions and exciton mobility in the molecule. This presents opportunities for utilizing upconversion luminescence to examine cellular microenvironments.
By showcasing how internal energy mobility can be engineered for improved efficiency, the Kobe team proposes an expansive design strategy that could lead to innovative classes of high-performance upconverters. Kobori mentioned, “We anticipate that this advancement may aid in addressing global energy challenges, as well as broaden into diverse fields like cancer treatment and diagnostics, utilizing harmless low-energy light and in-situ upconversion.”
Research Report: Vibronic Trimer Design Enhancing Intramolecular Triplet-Exciton Hopping to Accelerate Triplet-Triplet Annihilation for Photon Upconversion
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