Charge-Transfer Cocrystal via a Persistent Radical Cation Acceptor for Efficient Solar-Thermal Conversion

Area of Science:

• Materials Science
• Photochemistry
• Renewable Energy

Background:

• Designing organic charge-transfer (CT) cocrystals for efficient solar-thermal conversion is a significant challenge.
• Existing materials often struggle to capture the full solar spectrum effectively.

Purpose of the Study:

• To construct a unique CT cocrystal for efficient solar-thermal conversion.
• To investigate the material's performance in solar-driven interfacial evaporation.

Main Methods:

• Synthesized a CT cocrystal using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS radical cation) as the electron acceptor and 3,3',5,5'-tetramethylbenzidine as the donor.
• Characterized the cocrystal's properties, including electron delocalization and light absorption.
• Evaluated the cocrystal's performance in solar-driven interfacial evaporation under 1 sun irradiation.

Main Results:

• The synthesized cocrystal exhibited a high degree of electron delocalization due to the persistent ABTS radical cation.
• The material effectively captured the full solar spectrum, leading to distinguished photothermal efficiency.
• Achieved a high evaporation rate of 1.407 kg m⁻² h⁻¹ and a solar-to-vapor efficiency of 97.0% for solar-driven interfacial evaporation.

Conclusions:

• Rational engineering of radical cations can lead to advanced charge-transfer functional materials.
• The developed CT cocrystal shows great potential for efficient solar-thermal energy applications, particularly in solar-driven interfacial evaporation.