Singlet Fission¶
Overview¶
Singlet fission is a spin-allowed photophysical process in which one photoexcited singlet exciton splits into two triplet excitons on neighboring chromophores. Since a single absorbed photon generates two excited states, singlet fission has attracted considerable attention for improving the efficiency of photovoltaic devices beyond the Shockley–Queisser limit.
The efficiency of singlet fission depends strongly on molecular packing, electronic coupling, energy matching, and vibronic interactions.
Computational Studies¶
Computational chemistry has become indispensable for understanding singlet-fission mechanisms and designing efficient chromophores.
Modern theoretical approaches investigate
- Excited-state electronic structure
- Excitonic coupling
- Charge-transfer intermediates
- Multiexciton formation
- Vibronic coupling
- Quantum coherence during energy transfer
Density Functional Theory, multireference electronic structure methods, quantum dynamics, and Multi-Configuration Time-Dependent Hartree (MCTDH) simulations are widely employed to describe ultrafast singlet-fission dynamics.
These computational approaches provide valuable insight into molecular design strategies for next-generation organic photovoltaic materials.