- Title
- A dynamic Monte Carlo study of anomalous current voltage behaviour in organic solar cells
- Creator
- Feron, K.; Zhou, X.; Belcher, W. J.; Fell, C. J.; Dastoor, P. C.
- Relation
- Journal of Applied Physics Vol. 116, Issue 21
- Publisher Link
- http://dx.doi.org/10.1063/1.4903530
- Publisher
- American Institute of Physics
- Resource Type
- journal article
- Date
- 2014
- Description
- We present a dynamic Monte Carlo (DMC) study of s-shaped current-voltage (I-V) behaviour in organic solar cells. This anomalous behaviour causes a substantial decrease in fill factor and thus power conversion efficiency. We show that this s-shaped behaviour is induced by charge traps that are located at the electrode interface rather than in the bulk of the active layer, and that the anomaly becomes more pronounced with increasing trap depth or density. Furthermore, the s-shape anomaly is correlated with interface recombination, but not bulk recombination, thus highlighting the importance of controlling the electrode interface. While thermal annealing is known to remove the s-shape anomaly, the reason has been not clear, since these treatments induce multiple simultaneous changes to the organic solar cell structure. The DMC modelling indicates that it is the removal of aluminium clusters at the electrode, which act as charge traps, that removes the anomalous I-V behaviour. Finally, this work shows that the s-shape becomes less pronounced with increasing electron-hole recombination rate; suggesting that efficient organic photovoltaic material systems are more susceptible to these electrode interface effects.
- Subject
- charge carriers; active layer; excitons; aluminum; cathodes
- Identifier
- http://hdl.handle.net/1959.13/1061722
- Identifier
- uon:17001
- Identifier
- ISSN:0021-8979
- Rights
- © American Institute of Physics
- Language
- eng
- Full Text
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