A quantum discovery at room temperature
Scientists have identified a new quantum mechanism that could transform how energy moves through advanced materials. Prof. Kaifeng Wu's team at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, discovered a process called proton shuttle-assisted triplet energy transfer (PS-TET) that operates at room temperature.
Published in _Nature Materials_, the discovery reveals how proton motion can subtly yet powerfully influence triplet energy transfer — a process fundamentally important in both natural and synthetic systems.
How the proton shuttle works
When ZnSe quantum dots absorb light, they become excited and trigger a linked sequence of steps. First, a positive charge moves from ZnSe to phenol while a proton shifts from phenol to pyridine. Next, an electron transfers from ZnSe to the phenoxyl radical, accompanied by the proton moving back.
Even though the proton ultimately returns to its starting position, it plays a critical role as a shuttle. This temporary movement boosts both the speed and efficiency of triplet energy transfer compared to similar systems lacking this feature.
Quantum tunneling at room temperature
The researchers observed that the PS-TET process remains largely unaffected by temperature — suggesting the proton moves through quantum mechanical tunneling rather than classical motion. Calculations of proton vibrational wavefunction overlap integrals support this interpretation.
These findings show that quantum effects can be used to control how charge and energy move through complex materials, even at room temperature.
Implications for technology
"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.
Improving triplet formation can enhance photoredox and environmental catalysis. On the other hand, devices like solar cells and lasers often need to limit triplet formation to perform efficiently. The study suggests that adding or removing a proton shuttle could provide a way to control triplet formation on demand — offering a new dial for designing advanced materials.
This breakthrough opens new possibilities for controlling energy flow at the molecular level, with potential applications in catalysis, solar energy, and optoelectronics.
