Synergistic Two-Electron Transfer Enables Minute-Scale Redox Accumulation under Low-Light Conditions

Area of Science:

• * Artificial photosynthesis and renewable energy storage.
• * Molecular design for solar fuel conversion.

Background:

• * Converting sunlight to chemical fuels is crucial for renewable energy.
• * Accumulating multiple redox equivalents is essential for fuel formation but challenging under low light.
• * Key challenges include redox state persistence and preventing charge recombination.

Purpose of the Study:

• * To address challenges in accumulating redox equivalents for solar fuel production.
• * To develop a molecular system for efficient two-electron transfer under low solar irradiance.
• * To advance molecular approaches to artificial photosynthesis.

Main Methods:

• * Designed a covalently linked molecular triad: ruthenium-based photosensitizer, two-electron acceptor, and terminal electron relay.
• * Investigated electron transfer dynamics and redox equivalent accumulation using light excitation and ascorbate.
• * Analyzed system performance under sunlight-level irradiances.

Main Results:

• * Developed a molecular system enabling millisecond-scale electron storage via a terminal relay.
• * Achieved reversible two-electron accumulation on a minute time scale via disulfide bond cleavage and protonation.
• * Demonstrated suppressed charge recombination and efficient redox accumulation under low light conditions.
• * Utilized a peripheral relay design to enhance stability and efficiency.

Conclusions:

• * The novel molecular design effectively overcomes key challenges in solar fuel generation.
• * This strategy enables efficient solar-driven multielectron chemistry.
• * Findings advance molecular approaches to artificial photosynthesis and renewable energy storage.