Field-enhanced recombination at low temperatures in an organic photovoltaic blend
Physical Review B: Condensed Matter and Materials Physics
American Physical Society
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Athanasopoulos, S., Greenham, N., & Friend, R. (2015). Field-enhanced recombination at low temperatures in an organic photovoltaic blend. Physical Review B: Condensed Matter and Materials Physics, 92 (12530)https://doi.org/10.1103/PhysRevB.92.125301
We report on the non-trivial field dependence of charge carrier recombination in an organic blend at low temperatures. A new microwave resonance technique for monitoring charge recombination in organic semiconductors at low temperatures is applied in bulk heterojunction P3HT:PCBM blends with results showing that an external electric field can in fact increase recombination. Monte Carlo simulations suggest that this contradiction to conventional wisdom relates to electron-hole pairs that are separated at donor-acceptor interfaces where the electric field acts in synergy with their Coulomb attraction. For this behaviour to occur a critical initial separation of ~ 5nm between the carriers is required.
This work is supported by the UK Engineering and Physical Sciences Research Council (grant number EP/G060738/1). We thank H. Bouchiat for fruitful discussions and support in the fabrication of the resonators and S. Bayliss for carefully reading the manuscript and providing comments. A.C. acknowledges support from the E. Oppenheimer Foundation and St Catharine's College, Cambridge. Part of the Monte Carlo simulations were performed using the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council.
External DOI: https://doi.org/10.1103/PhysRevB.92.125301
This record's URL: https://www.repository.cam.ac.uk/handle/1810/248917
Attribution-NonCommercial 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by-nc/2.0/uk/
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