Bardeen Research Group

Department of Chemistry | University of California @ Riverside | 501 Big Springs Road | 127-131 CS-1

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Bardeen Research Group
University of California, Riverside * Department of Chemistry
501 Big Springs Rd * Riverside, CA 92521, USA
Phone: +1.951.827.2723 * Fax: +1.951.827.4713 * Email: christob@ucr.edu

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ChemPhysLett
Spotlight:Research

Magnetic Field Effects and the Role of Spin States in Singlet Fission

  Singlet fission is a photophysical process that has promise for increasing the efficiency of solar cells. The dynamics depend on the triplet spin states and can be influenced by external magnetic fields.

In 4-electron systems, fission takes an initial singlet state into a superposition of triplet pair states. Direct eveidence for this superposition state is provided by quantum beats in the delayed fluorescence of tetracene crystals. The beat frequencies depend on the crystal orientation with respect to the magnetic field, consistent with predictions based on solving the full spin Hamiltonian.

Magnetic field effects on the kinetics are analyzed in terms of a hybrid quantum-kinetic model. The magnetic field has no effect on teh initial fluorscence decay rate but affects the decay after the triplet pair states begin to equilibrate with the singlets. The long-time behavior of the fluorescence decay reflects association and separation of triplet pairs and relaxation into different spin states.

 

 

For more information, check out our paper
Magnetic Field Effects and the Role of Spin States in Singlet Fission

Chem. Phys. Lett.
, in press October 2013