Origin of reduced polaron recombination in organic semiconductor devices

By Carsten Deibel, A. Wagenpfahl, V. Dyakonov. 2009

137 citations recorded by the source corpus.

We propose a model to explain the reduced bimolecular recombination rate found in state-of-the-art bulk heterojunction solar cells. When compared to the Langevin recombination, the experimentally observed rate is one to four orders of magnitude lower, but gets closer to the Langevin case for low temperatures. Our model considers the organic solar cell as device with carrier concentration gradients, which form due to the electrode/blend/electrode device configuration. The resulting electron concentration under working conditions of a solar cell is higher at the cathode than at the anode, and vice versa for holes. Therefore, the spatially dependent bimolecular recombination rate, proportional to the local product of electron and hole concentration, is much lower as compared to the calculation of the recombination rate based on the extracted and thus averaged charge carrier concentrations. We consider also the temperature dependence of the recombination rate, which can for the first time be described with our model.

Subfields: Electrical and Electronic Engineering, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/b0ffa5c814c8d5822d09229bcf0488224327cb29

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In Electrical and Electronic Engineering

1. V. Dyakonov
2. Carsten Deibel
3. Andreas Baumann
4. Julia Schafferhans
5. A. Wagenpfahl

In Polymers and Plastics

1. Carsten Deibel
2. V. Dyakonov
3. A. Wagenpfahl

Citations in the corpus

• Oxygen doping of P3HT:PCBM blends: Influence on trap states, charge carrier mobility and solar cell performance (2010, methodology): “In order to understand the influence of a decreased mobility as well as charge carrier doping on the solar cell parameters, we performed macroscopic simulations based on solving the differential equation system of the Poisson, the continuity and the drift–diffusion equations in one dimension [19, 20”
• Polymer–fullerene bulk heterojunction solar cells (2010, background): “Only recently, a model has been proposed which considers the organic solar cell as a device with carrier concentration gradients formed due to the electrode/blend/electrode device configuration [142].”