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Updated: Aug 2, 2025
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Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light
Published on: September 12, 2014
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Sensitized Singlet Fission in Rigidly Linked Axial and Peripheral Pentacene-Subphthalocyanine Conjugates
Henrik Gotfredsen1,2,3, Dominik Thiel4, Phillip M Greißel4
1Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
Journal of the American Chemical Society
|April 21, 2023
Summary
Singlet fission (SF) research for solar energy is advanced by studying sensitizer-chromophore geometry. A peripheral arrangement significantly accelerates energy transfer in SF model systems due to favorable transition dipole moment orientation.
Area of Science:
- Materials Science
- Photochemistry
- Renewable Energy
Background:
- Singlet fission (SF) is a promising process for enhancing solar energy conversion by generating two triplet excitons from one singlet exciton.
- Covalently linked chromophore dimers are essential for understanding SF mechanisms, with sensitizers expanding spectral absorption.
- Controlling chromophore arrangement is key to optimizing SF efficiency.
Purpose of the Study:
- To investigate the impact of sensitizer-chromophore geometry on singlet fission efficiency in a model system.
- To synthesize and characterize pentacene dimer-subphthalocyanine conjugates with axial and peripheral arrangements.
- To elucidate the relationship between molecular geometry, energy transfer rates, and SF performance.
Main Methods:
- Synthesis of two conjugates: pentacene dimer linked to subphthalocyanine via an alkynyl bridge in axial and peripheral configurations.
- Steady-state and time-resolved photophysical measurements to assess energy transfer and triplet quantum yields.
- Theoretical evaluation of dipolar coupling (V_dip^2) and orientation factor (κ^2) to explain observed kinetics.
Main Results:
- Both synthesized conjugates demonstrated efficient energy transfer and high triplet quantum yields, confirming successful SF.
- Energy transfer in the peripheral conjugate was approximately 26 times faster than in the axial conjugate.
- The accelerated rate in the peripheral arrangement was attributed to a more favorable, nearly co-planar orientation of transition dipole moments.
Conclusions:
- Sensitizer-chromophore geometry critically influences the rate of energy transfer in SF systems.
- Peripheral arrangements, offering favorable transition dipole moment orientations, can significantly enhance SF efficiency.
- This study provides crucial insights for designing advanced materials for solar energy applications leveraging singlet fission.
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