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Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
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Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with
Lei Wang1, Jacek Jakowski2, Sophya Garashchuk1
1Department of Chemistry and Biochemistry, University of South Carolina , Columbia, South Carolina 29208, United States.
Journal of Chemical Theory and Computation
|August 10, 2016
Summary
Deuterium substitution in poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) blends affects charge transfer. Quantum effects on energy gaps may explain experimental trends in organic solar cells.
Area of Science:
- Materials Science
- Physical Chemistry
- Organic Electronics
Background:
- Polymer:fullerene blends like P3HT:PCBM are key in organic photovoltaics.
- Deuterium substitution is an experimental technique to tune material properties.
Purpose of the Study:
- To investigate the impact of deuterium substitution on the open circuit voltage in P3HT:PCBM blends.
- To understand the role of quantum effects in isotopic substitution.
Main Methods:
- Utilized a 221-atom model of a polymer-wrapped PCBM molecule.
- Employed a quantum trajectory/electronic structure approach with nonlinear corrections for nuclear wave functions.
- Generated classical forces using density functional tight binding (DFTB).
Main Results:
- Isotopic substitution showed a negligible effect on electronic energy levels.
- Quantum-induced fluctuations in the energy gap were observed.
- These fluctuations may promote charge transfer and increase charge recombination in deuterated P3HT:PCBM.
Conclusions:
- Quantum effects, not electronic level shifts, are crucial for understanding isotope effects in P3HT:PCBM.
- Deuteration can influence charge transfer dynamics and recombination in organic solar cells.
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