Equilibrated charge carrier populations govern steady-state nongeminate recombination in disordered organic solar cells

We employed bias-assisted charge extraction techniques to investigate the transient and steady-state recombination of photogenerated charge carriers in complete devices of a disordered polymer-fullerene blend. Charge recombination is shown to be dispersive, with a significant slowdown of the recombi...

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Main Authors: Roland, Steffen (Author) , Kniepert, Juliane (Author) , Love, John A. (Author) , Negi, Vikas (Author) , Liu, Feilong (Author) , Bobbert, Peter (Author) , Melianas, Armantas (Author) , Kemerink, Martijn (Author) , Hofacker, Andreas (Author) , Neher, Dieter (Author)
Format: Article (Journal)
Language:English
Published: March 4, 2019
In: The journal of physical chemistry letters
Year: 2019, Volume: 10, Issue: 6, Pages: 1374-1381
ISSN:1948-7185
DOI:10.1021/acs.jpclett.9b00516
Online Access:Verlag, Volltext: https://doi.org/10.1021/acs.jpclett.9b00516
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Author Notes:Steffen Roland, Juliane Kniepert, John A. Love, Vikas Negi, Feilong Liu, Peter Bobbert, Armantas Melianas, Martijn Kemerink, Andreas Hofacker, and Dieter Neher
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Summary:We employed bias-assisted charge extraction techniques to investigate the transient and steady-state recombination of photogenerated charge carriers in complete devices of a disordered polymer-fullerene blend. Charge recombination is shown to be dispersive, with a significant slowdown of the recombination rate over time, consistent with the results from kinetic Monte Carlo simulations. Surprisingly, our experiments reveal little to no contributions from early time recombination of nonequilibrated charge carriers to the steady-state recombination properties. We conclude that energetic relaxation of photogenerated carriers outpaces any significant nongeminate recombination under application-relevant illumination conditions. With equilibrated charges dominating the steady-state recombination, quasi-equilibrium concepts appear suited for describing the open-circuit voltage of organic solar cells despite pronounced energetic disorder.
Item Description:Gesehen am 26.11.2019
Vom Autor zitiert als: Thermalized carrier populations govern steady state non-geminate recombination in disordered organic solar cells
Physical Description:Online Resource
ISSN:1948-7185
DOI:10.1021/acs.jpclett.9b00516