Photocarrier drift distance in organic solar cells and photodetectors
Stolterfoht, M., Armin, A., Philippa, B., White, R.D., Burn, P.L., Meredith, P., Juška, G. and Pivrikas, A. (2015) Photocarrier drift distance in organic solar cells and photodetectors. Scientific Reports, 5 . Article 9949.
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Light harvesting systems based upon disordered materials are not only widespread in nature, but are also increasingly prevalent in solar cells and photodetectors. Examples include organic semiconductors, which typically possess low charge carrier mobilities and Langevin-type recombination dynamics - both of which negatively impact the device performance. It is accepted wisdom that the "drift distance'' (i.e., the distance a photocarrier drifts before recombination) is defined by the mobility-lifetime product in solar cells. We demonstrate that this traditional figure of merit is inadequate for describing the charge transport physics of organic light harvesting systems. It is experimentally shown that the onset of the photocarrier recombination is determined by the electrode charge and we propose the mobility-recombination coefficient product as an alternative figure of merit. The implications of these findings are relevant to a wide range of light harvesting systems and will necessitate a rethink of the critical parameters of charge transport.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Engineering and Information Technology|
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