Researchers in China have identified a new mechanism that uses proton movement to speed up energy transfer in materials. The process, observed in quantum dots, relies on quantum tunneling at room temperature. It could help improve solar cells, lasers and catalysts.
A team led by Prof. Kaifeng Wu at the Dalian Institute of Chemical Physics discovered the proton shuttle-assisted triplet energy transfer, or PS-TET. In experiments, energy moved from ZnSe-based colloidal quantum dots to phenol-pyridine dyads on their surfaces. A proton shifts position briefly to coordinate electron and hole movement before returning to its starting point.
The shuttle increased both the speed and efficiency of the transfer compared with a version lacking the proton. The rate changed little with temperature, indicating the proton moves via quantum mechanical tunneling rather than heat-driven steps.
"The discovery of the PS-TET mechanism has profound implications for many modern molecular technologies involving the spin-triplet excited states of molecules," Prof. Wu noted. The findings suggest that adding or removing such a shuttle could allow scientists to tune triplet formation in devices as needed.