Colloidal quantum dots (QDs) have long been a fascinating area of research, offering a versatile platform for exploring various quantum effects under ambient conditions. Their unique size-dependent colors provide a vivid demonstration of the quantum confinement effect, revealing even more exotic quantum behaviors, including single-photon emission and exciton coherence.
In recent years, QDs have revealed novel quantum behaviors that challenge traditional solid-state quantum platforms. Unlike other solid-state quantum platforms, QDs can be handled in solution like molecules, enabling the functionalization of their surfaces with organic molecules to drive photochemical processes.
The ability of colloidal QDs to maintain strong room-temperature spin quantum coherence while participating in photochemistry has inspired Prof. Kaifeng Wu and his team at the Dalian Institute of Chemical Physics, part of the Chinese Academy of Sciences, to pioneer a new interdisciplinary field: leveraging the quantum coherence of QDs to control photochemical reactions.
This idea is closely linked to a fascinating example of quantum biology, where migratory animals are believed to use the Earth’s magnetic field to coherently modulate spin-triplet recombination yields of photogenerated radical pairs and trigger navigation. This concept has been explored in various studies, but recent breakthroughs have shown that QDs can indeed harness this principle for manipulating photochemical reactions.
In a study published on January 6 in Nature Materials, Prof. Wu’s team demonstrated the hybrid radical pairs prepared from colloidal QDs and their surface-anchored molecules, showcasing the unique “quantum advantage” of hybrid radical pairs in quantum coherent control of triplet photochemistry.
Unlike pure organic radical pairs featuring similar Landé g-factors, QDs’ large Δg values enabled direct observation of the radical-pair spin quantum beats, which were previously hidden in studies. Moreover, researchers can now control these magnetic field effects through QD size and composition, a unique advantage over previous pure organic radical pairs.
“The hybrid radical pairs and their strong tunable magnetic field effect reported in this study will significantly benefit the spin-control over molecular and hybrid inorganic/organic optoelectronics,” said Prof. Wu. “Hybrid radical pairs may constitute a unique material platform to merge the field of emerging molecular quantum sciences with solid-state quantum platforms.”
“Hybrid radical pairs may also enable many novel quantum information technologies,” he added, highlighting their potential for widespread applications.
Recent Highlights:
- Hybrid radical pairs show strong magnetic field control over triplet recombination dynamics
- QDs’ unique size-dependent colors provide vivid demonstrations of the quantum confinement effect under ambient conditions
- Functionalization of QD surfaces enables the development of powerful tools for driving photochemical processes
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