Relating the open-circuit voltage to interface molecular properties of donor:acceptor bulk heterojunction solar cells
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- 10 March 2010
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 81 (12)
- https://doi.org/10.1103/physrevb.81.125204
Abstract
The open-circuit voltage (Voc) of polymer:fullerene bulk heterojunction solar cells is determined by the interfacial charge-transfer (CT) states between polymer and fullerene. Fourier-transform photocurrent spectroscopy and electroluminescence spectra of several polymer:fullerene blends are used to extract the relevant interfacial molecular parameters. An analytical expression linking these properties to Voc is deduced and shown to be valid for photovoltaic devices comprising three commonly used conjugated polymers blended with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Voc is proportional to the energy of the CT states ECT. The energetic loss q$\Delta${}V between ECT and qVoc vanishes when approaching 0 K. It depends linearly on T and logarithmically on illumination intensity. Furthermore q$\Delta${}V can be reduced by decreasing the electronic coupling between polymer and fullerene or by reducing the nonradiative recombination rate. For the investigated devices we find a loss q$\Delta${}V of $\sim${}0.6$\hskip0.3em${}eV at room temperature and under solar illumination conditions, of which $\sim${}0.25$\hskip0.3em${}eV is due to radiative recombination via the CT state and $\sim${}0.35$\hskip0.3em${}eV is due to nonradiative recombination.Keywords
This publication has 40 references indexed in Scilit:
- Polymer solar cells with enhanced open-circuit voltage and efficiencyNature Photonics, 2009
- On the origin of the open-circuit voltage of polymer–fullerene solar cellsNature Materials, 2009
- Bulk heterojunction solar cells with internal quantum efficiency approaching 100%Nature Photonics, 2009
- Polymer‐Fullerene Bulk‐Heterojunction Solar CellsAdvanced Materials, 2009
- Polymer–Fullerene Composite Solar CellsAngewandte Chemie International Edition, 2007
- Offset energies at organic semiconductor heterojunctions and their influence on the open-circuit voltage of thin-film solar cellsPhysical Review B, 2007
- Design Rules for Donors in Bulk‐Heterojunction Solar Cells—Towards 10 % Energy‐Conversion EfficiencyAdvanced Materials, 2006
- Correlation between oxidation potential and open-circuit voltage of composite solar cells based on blends of polythiophenes/ fullerene derivativeApplied Physics Letters, 2004
- Cathode dependence of the open-circuit voltage of polymer:fullerene bulk heterojunction solar cellsJournal of Applied Physics, 2003
- Detailed Balance Limit of Efficiency of p-n Junction Solar CellsJournal of Applied Physics, 1961