Singlet Fission in Carbene-Derived Diradicaloids

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Singlet fission (SF) is a photophysical process that can generate two electron-hole pairs from one high-energy photon, making it promising for advanced solar cell technologies.
• Developing efficient SF materials requires precise control over molecular structure and excited-state properties.

Purpose of the Study:

• To introduce a new class of SF materials based on diradicaloid cyclic (alkyl)(amino)carbenes (CAACs).
• To demonstrate tunable SF properties by modifying steric and diradical character.
• To achieve intermolecular SF in solution.

Main Methods:

• Synthesis of CAAC-based diradicaloids with tunable steric and diradical properties.
• Systematic modification of excited-state energy landscapes.
• Observation of intermolecular SF in solution via dimer self-assembly at cryogenic temperatures.

Main Results:

• A new class of SF materials based on CAAC scaffolds was successfully synthesized.
• The modular approach allowed fine-tuning of key SF criteria (steric factor and diradical character).
• The first example of intermolecular SF in solution was achieved through dimer self-assembly at cryogenic temperatures.

Conclusions:

• CAACs represent a versatile platform for designing novel SF materials.
• The ability to tune SF properties offers a pathway to optimize materials for energy applications.
• Solution-phase intermolecular SF at cryogenic temperatures is feasible, opening new avenues for SF research.