Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-19T23:00:09.505Z Has data issue: false hasContentIssue false

Variation of the Photocurrent Spectra due to Energy Dependent Hole Mobility in Organic Bulk Hetero-junction Solar Cells

Published online by Cambridge University Press:  13 August 2012

Buddika K. Abeyweera
Affiliation:
Dept. of Electrical & Computer Engineering, University of Louisville, Louisville, KY. U.S.A.
Bruce W. Alphenaar
Affiliation:
Dept. of Electrical & Computer Engineering, University of Louisville, Louisville, KY. U.S.A.
Get access

Abstract

A comparison of the photocurrent spectra of organic bulk heterojunction solar cells of various thicknesses is presented. Increasing the thickness of the active layer in both MDMO-PPV /PCBM and P3HT/PCBM solar cells reduces the magnitude of the photocurrent due to the low mobility of the photogenerated holes. Measurements show that the photocurrent reduction is predominately due to a loss in carriers generated at the polymer absorption maximum, while the low energy response is relatively unaffected. In a thick enough sample, the low energy response (1.5-2 eV) dominates, and a photocurrent peak is no longer observed at the main absorption maximum (2.6 eV). The results imply that hole transport is blocked for carriers generated in the polymer at higher energy. Because these holes are generated at the absorption maximum their low mobility could be a major factor limiting solar cell efficiency.

Type
Articles
Copyright
Copyright © Materials Research Society 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Li, G., Shrotriya, V., Huang, J., Yao, Y., Moriarty, T., Emery, K. and Yang, Y., Nature Materials 4 (11), 864868 (2005).Google Scholar
2. Coakley, M. M. K., M., D.;, Chem. Mater. 16(23) (2004).Google Scholar
3. Yu, G., ;Heeger, A., J., Journal of Applied Phyiscs 78(7) (1995).Google Scholar
4. Mihaliletchi, V., D.; Duren, J., K., J., Blom, P., W., M.,Hummelen, J., C.,Janssen, R., A., J.,;, Advanced Functional Materials 13(1) (2003).Google Scholar
5. Yang, F., Shtein, M. and Forrest, S. R., Nature Materials 4(1), 3741 (2004).Google Scholar
6. Yang, P. T. C., Homg, S., Lee, K., TzengFan, S., Applied Physics Letters 92, 083504–083503 (2008).Google Scholar
7. Ma, W. Y., C.;Gong, X.;Lee, K.;Heeger, A., Advanced Functional Materials 15 (2005).Google Scholar
8. Wienk, M. M., Kroon, J. M., Verhees, W. J., Knol, J., Hummelen, J. C., van Hal, P. A. and Janssen, R. A., Angew Chem Int Ed Engl 42 (29), 33713375 (2003).Google Scholar