Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy
The current-voltage characteristic and the performance of organic bulk-heterojunction solar cells are very sensitive to small variations in the production steps or environmental influences. In our experiments, we found a large variation of the short-circuit current, which does not correspond to the...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2007
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| _version_ | 1797099309914652672 |
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| author | Glatthaar, M Riede, M Keegan, N Sylvester-Hvid, K Zimmermann, B Niggemann, M Hinsch, A Gombert, A |
| author_facet | Glatthaar, M Riede, M Keegan, N Sylvester-Hvid, K Zimmermann, B Niggemann, M Hinsch, A Gombert, A |
| author_sort | Glatthaar, M |
| collection | OXFORD |
| description | The current-voltage characteristic and the performance of organic bulk-heterojunction solar cells are very sensitive to small variations in the production steps or environmental influences. In our experiments, we found a large variation of the short-circuit current, which does not correspond to the device thickness as one might expect. The fill factor of some devices is below 25% under illumination, while the best devices have a fill factor of about 70%. Electrical impedance spectroscopy can provide information about the conductivity of different regions within the device. In earlier measurements, it was observed that devices with a thick absorber layer might consist of a conductive bulk region and a very poorly conductive depletion region at the metal contact. Using a standard semiconductor device model, it is shown in this paper that this reduces the charge collection efficiency under short-circuit conditions, as there is no electrical field in the bulk region, supporting the charge separation. For devices with the low fill factor, a thin-current limiting layer under forward bias can be identified by electrical impedance spectroscopy and is suggestive of a corroded metal contact. © 2006 Elsevier B.V. All rights reserved. |
| first_indexed | 2024-03-07T05:21:58Z |
| format | Journal article |
| id | oxford-uuid:df37c071-40c2-4d00-ba22-fe256f9d6d54 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:21:58Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:df37c071-40c2-4d00-ba22-fe256f9d6d542022-03-27T09:37:55ZEfficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:df37c071-40c2-4d00-ba22-fe256f9d6d54EnglishSymplectic Elements at Oxford2007Glatthaar, MRiede, MKeegan, NSylvester-Hvid, KZimmermann, BNiggemann, MHinsch, AGombert, AThe current-voltage characteristic and the performance of organic bulk-heterojunction solar cells are very sensitive to small variations in the production steps or environmental influences. In our experiments, we found a large variation of the short-circuit current, which does not correspond to the device thickness as one might expect. The fill factor of some devices is below 25% under illumination, while the best devices have a fill factor of about 70%. Electrical impedance spectroscopy can provide information about the conductivity of different regions within the device. In earlier measurements, it was observed that devices with a thick absorber layer might consist of a conductive bulk region and a very poorly conductive depletion region at the metal contact. Using a standard semiconductor device model, it is shown in this paper that this reduces the charge collection efficiency under short-circuit conditions, as there is no electrical field in the bulk region, supporting the charge separation. For devices with the low fill factor, a thin-current limiting layer under forward bias can be identified by electrical impedance spectroscopy and is suggestive of a corroded metal contact. © 2006 Elsevier B.V. All rights reserved. |
| spellingShingle | Glatthaar, M Riede, M Keegan, N Sylvester-Hvid, K Zimmermann, B Niggemann, M Hinsch, A Gombert, A Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title | Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title_full | Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title_fullStr | Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title_full_unstemmed | Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title_short | Efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
| title_sort | efficiency limiting factors of organic bulk heterojunction solar cells identified by electrical impedance spectroscopy |
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