Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9812078 | Thin Solid Films | 2005 | 5 Pages |
Abstract
The working principle of organic bulk-heterojunction solar cells is a widely discussed topic. For thin film solar cells it is commonly supposed that the built-in potential Vbi is the driving force for charge separation and determines the open-circuit voltage Voc. In former works, Vbi was estimated by measuring Voc in the saturation regime. To check the validity of this model, the direct measurement of the built-in potential is desirable. We have investigated the origin of the open-circuit voltage of organic bulk-heterojunction solar cells by means of electroabsorption spectroscopy. This technique allows measurement of the built-in potential directly and therefore permits an independent measurement of Vbi and Voc. In our experiments on indium tin oxide/poly(3,4-ethylendioxythiophene)Â :Â poly(styrene-sulfonate)/poly(2 -methoxy-5-(3â²,7â²-dimethyloktyloxy)-p-phenylene-vinylene)Â :Â 1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6)C61/metal bulk-heterojunction solar cells no significant correlation between the open-circuit voltage and the built-in potential was observed. For certain electrode materials, i.e. gold and copper, Voc exceeded Vbi which is revealing of semipermeable membranes.
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Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
B. Zimmermann, M. Glatthaar, M. Niggemann, M. Riede, A. Hinsch,