Journal article
Kinetics of charge transfer processes in organic solar cells: Implications for the design of acceptor molecules
Organic Electronics: physics, materials, applications, Vol.13(11), pp.2538-2545
2012
Abstract
We report the electronic properties of a new class of non-fullerene electron acceptor molecules with electron affinities tunable over an approximately 1 eV range. This tunability allows us to vary the thermodynamic driving force for electron transfer (ΔG°) such that it is equal-and-opposite-to the reorganization energy for the ionized states (λ). We utilize this design principle, derived from Marcus-Hush theory, to optimize the rate of charge transfer in blends of these acceptors with poly(3-n-hexylthiophene-2,5-diyl) (P3HT) - a standard organic solar cell donor material. We show that computationally inexpensive calculations can be used to parameterize Marcus-Hush theory so as to correctly predict whether quenching will occur. Arguments based solely on energetics are common in the literature and we show that such theories do not predict the trends observed in our photoluminescence quenching experiments. This is the case whether the energies determined from experiments [cyclic voltammetry (CV) and the optical gap] or calculated from density functional theory for the solid state. We predict essentially barrier-less photoelectron transfer (PET) from P3HT to the acceptor 2-[{7-(9,9-di-n-propyl-9H-fluoren-2-yl)benzo[c] [1,2,5] thiadiazol-4-yl} methylene]malononitrile (or K12), consistent with the experimental photoluminescence quenching efficiencies found for P3HT:K12 blends. Our results clearly show that energetics alone is not sufficient to predict PET between the acceptor-donor pair, and that kinetics are an important determining factor.
Details
- Title
- Kinetics of charge transfer processes in organic solar cells: Implications for the design of acceptor molecules
- Authors
- Paul E Schwenn (Author) - University of QueenslandKe Gui (Author) - University of QueenslandYuliang Zhang (Author) - University of QueenslandPaul L Burn (Author) - University of QueenslandPaul Meredith (Author) - University of QueenslandBenjamin J Powell (Author) - University of Queensland
- Publication details
- Organic Electronics: physics, materials, applications, Vol.13(11), pp.2538-2545
- Publisher
- Elsevier BV, North-Holland
- DOI
- 10.1016/j.orgel.2012.07.008
- ISSN
- 1566-1199
- Organisation Unit
- University of the Sunshine Coast, Queensland; Thompson Institute
- Language
- English
- Record Identifier
- 99450877502621
- Output Type
- Journal article
Metrics
68 Record Views
InCites Highlights
These are selected metrics from InCites Benchmarking & Analytics tool, related to this output
- Web Of Science research areas
- Materials Science, Multidisciplinary
- Physics, Applied
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Source: InCites