Robust organic radical cations with near-unity absorption across solar spectrum

Area of Science:

• Materials Science
• Photothermal Conversion
• Solar Energy

Background:

• Efficient solar energy utilization is crucial for sustainable development.
• Developing effective photothermal materials is key for applications like water desalination.
• Organic radical cations offer potential as advanced solar absorbers.

Purpose of the Study:

• To investigate the use of robust organic radical cations for efficient solar-driven seawater evaporation.
• To synthesize gram-scale organic radical cations with near-unity solar absorption.
• To establish a highly efficient interfacial evaporation system using these materials.

Main Methods:

• Single-electron oxidation for synthesizing organic radical cations.
• Femtosecond transient absorption spectroscopy to study electron relaxation dynamics.
• Fabrication of an interfacial evaporation system using cellulose paper.

Main Results:

• Organic radical cations synthesized with near-unity absorption across the full solar spectrum.
• Rapid non-radiative relaxation of intervalence charge-transfer electrons (rate of 5.26 × 10^12 s^-1).
• Achieved a 97.2% solar-to-vapor conversion efficiency under one sun irradiation.

Conclusions:

• Organic radical cations are stable and effective near-unity solar absorbers.
• The developed interfacial evaporation system demonstrates exceptional efficiency.
• This research provides new strategies for designing photothermal materials for solar energy applications.