Three-step cascaded artificial light-harvesting systems with tunable efficiency based on metallacycles

Area of Science:

• Materials Science
• Photochemistry
• Supramolecular Chemistry

Background:

• Developing efficient multi-step cascaded artificial light-harvesting systems (ALHSs) with tunable efficiency remains a significant challenge.
• Existing systems often struggle with energy transfer losses and lack precise control over efficiency.

Purpose of the Study:

• To design and investigate novel cascaded ALHSs utilizing AIE-active metallacycles for enhanced light harvesting.
• To achieve efficient sequential three-step energy transfer from antenna to acceptor molecules.
• To demonstrate a strategy for regulating ALHS efficiency via hydrophilic and hydrophobic interactions.

Main Methods:

• Design of cascaded ALHS incorporating AIE-active metallacycles (MTPEPt1) as the antenna.
• Incorporation of Eosin Y (ESY) and sulforhodamine 101 (SR101) as intermediate energy conveyors.
• Utilizing near-infrared emissive chlorin-e6 (Ce6) as the final energy acceptor.
• Analysis of spectral overlap and molecular proximity for efficient energy transfer pathways.
• Investigation of hydrophilic and hydrophobic interactions to tune system efficiency.

Main Results:

• Successful design of a novel cascaded ALHS with efficient sequential three-step energy transfer (MTPEPt1 → ESY → SR101 → Ce6).
• Demonstrated close contact and adequate spectral overlap between donor and acceptor molecules at each energy transfer stage.
• Established a unique method for regulating ALHS efficiency by manipulating hydrophilic and hydrophobic interactions.

Conclusions:

• The developed cascaded ALHS exhibits efficient energy funneling to the near-infrared emissive Ce6.
• The strategy of adjusting hydrophilic and hydrophobic interactions offers a novel approach for tuning the efficiency of artificial light-harvesting systems.
• This work provides a foundation for developing advanced light-harvesting materials with controllable performance.