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Molecular Multilayer Organic Solar Cells with Large Excitonic Diffusion Length

Published online by Cambridge University Press:  26 February 2011

Seunghyup Yoo ,
William J Potscavage ,
Benoit Domercq ,
Sung-Ho Han ,
Dean Levi  and
Bernard Kippelen
Seunghyup Yoo
Affiliation:
syoo@ee.gatech.edu, Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA, 30332-0250, United States
William J Potscavage
Affiliation:
william.potscavage@ece.gatech.edu, Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA, 30332-0250, United States
Benoit Domercq
Affiliation:
benoit.domercq@ece.gatech.edu, Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA, 30332-0250, United States
Sung-Ho Han
Affiliation:
sung-ho_han@msn.com, NREL, Golden, CO, 80401, United States
Dean Levi
Affiliation:
dean_levi@nrel.gov, NREL, Golden, CO, 80401, United States
Bernard Kippelen
Affiliation:
bernard.kippelen@ece.gatech.edu, Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA, 30332-0250, United States
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Abstract

We report on the photovoltaic properties of organic solar cells based on pentacene and C60 thin films. A peak external quantum efficiency (EQE) of 69 % at a wavelength of λ = 668 nm is achieved upon optimization of the exciton blocking layer (EBL) thickness. Complex optical functions of pentacene films are measured as a function of wavelength by spectroscopic ellipsometry and used to analyze the EQE spectra. Detailed analysis of the EQE spectra indicate that the pentacene layers exhibit large excitonic diffusion lengths of ∼70 nm and that the performance improvement in EQE can be attributed to the influence of the thickness of the EBL layer on the carrier collection efficiency.

Keywords

photovoltaicorganicsemiconducting
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 965: Symposium S – Organic Electronics – Materials, Devices and Applications , 2006 , 0965-S11-01
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

[1] Xue, J. G., Uchida, S., Rand, B. P., and Forrest, S. R., Appl. Phys. Lett. 85 (2004) 5757.Google Scholar
[2] Ma, W., Yang, C., Gong, X., Lee, K., and Heeger, A. J., Adv. Funct. Mater. 15 (2005) 1617.Google Scholar
[3] Gregg, B. A., J. Phys. Chem. B 107 (2003) 4688.Google Scholar
[4] Forrest, S. R., MRS Bulletin 30 (2005) 28.Google Scholar
[5] Schmidt-Mende, L., Fechtenkotter, A., Mullen, K., Moons, E., Friend, R.H., MacKenzie, J. D., Science 293 (2001) 1119.Google Scholar
[6] Dimitrakopoulos, C. D. and Malenfant, P. R. L., Adv. Mater. 14 (2002) 99.Google Scholar
[7] Kelley, T. W., Boardman, L. D., Dunbar, T. D., Muyres, D. V., Pellerite, M. J., and Smith, T. P., J. Phys. Chem. B 107 (2003) 5877.Google Scholar
[8] Gundlach, D. J., Nichols, J. A., Zhou, L., and Jackson, T. N., Appl. Phys. Lett. 80 (2002) 2925.Google Scholar
[9] Cicoira, F., Santato, C., Dinelli, F., Murgia, M., Loi, M. A., Biscarini, F., Zamboni, R., Heremans, P., and Muccini, M., Adv. Funct. Mater. 15 (2005) 375.Google Scholar
[10] Yoo, S., Domercq, B., and Kippelen, B., Appl. Phys. Lett. 85 (2004) 5427.Google Scholar
[11] Mayer, A. C., Lloyd, M. T., Herman, D. J., Kasen, T. G., and Malliaras, G. G., Appl. Phys. Lett. 85 (2004) 6272.Google Scholar
[12] Chu, C.-W., Shao, Y., Shrotriya, V., and Yang, Y., Appl. Phys. Lett. 86 (2005) 243506.Google Scholar
[13] Park, S. P., Kim, S. S., Kim, J. H., Whang, C. N., and Im, S., Appl. Phys. Lett. 80 (2002) 2872.Google Scholar
[14] Han, S.-H., Yoo, S., Domercq, B., Kippelen, B., and Levi, D., in preparation.Google Scholar
[15] Pettersson, L. A. A., Roman, L. S., and Inganas, O., J. Appl. Phys. 86 (1999) 487.Google Scholar
[16] Peumans, P., Yakimov, A., and Forrest, S. R., J. Appl. Phys. 93 (2003) 3693.Google Scholar
[17] It is noted that estimated values for excitonic diffusion lengths can vary depending on the assumptions and boundary conditions used. However, the departure from the ideal condition imposed here tends to result in larger diffusion lengths, and therefore, chance for overestimation is minimized with the current assumptions. Also, there could be a batch-tobatch variation in excitonic diffusion lengths as they can sensitively vary depending on the extrinsic conditions such as impurities and contamination.Google Scholar
[18] Peumans, P. and Forrest, S. R., Appl. Phys. Lett. 79 (2001) 126.Google Scholar
[19] Parthasarathy, G., Burrows, P. E., Khalfin, V., Kozlov, V. G., and Forrest, S. R., Appl. Phys. Lett. 72 (1998) 2138.Google Scholar
[20] The metal source in the deposition system was approximately 1 meter below the substrate.Google Scholar
[21] Salzman, R. F., Xue, J., Rand, B. P., Alexander, A., Thompson, M. E., Forrest, S. R., Org. Electron. 6 (2005) 242.Google Scholar
[22] Shtein, M., Mapel, J., Bensiger, J. B., and Forrest, S. R., Appl. Phys. Lett. 81 (2002) 268.Google Scholar