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Molecular Multilayer Organic Solar Cells with Large Excitonic Diffusion Length

  • Seunghyup Yoo (a1), William J Potscavage (a2), Benoit Domercq (a3), Sung-Ho Han (a4), Dean Levi (a5) and Bernard Kippelen (a6)...

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.

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[1] Xue, J. G., Uchida, S., Rand, B. P., and Forrest, S. R., Appl. Phys. Lett. 85 (2004) 5757.
[2] Ma, W., Yang, C., Gong, X., Lee, K., and Heeger, A. J., Adv. Funct. Mater. 15 (2005) 1617.
[3] Gregg, B. A., J. Phys. Chem. B 107 (2003) 4688.
[4] Forrest, S. R., MRS Bulletin 30 (2005) 28.
[5] Schmidt-Mende, L., Fechtenkotter, A., Mullen, K., Moons, E., Friend, R.H., MacKenzie, J. D., Science 293 (2001) 1119.
[6] Dimitrakopoulos, C. D. and Malenfant, P. R. L., Adv. Mater. 14 (2002) 99.
[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.
[8] Gundlach, D. J., Nichols, J. A., Zhou, L., and Jackson, T. N., Appl. Phys. Lett. 80 (2002) 2925.
[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.
[10] Yoo, S., Domercq, B., and Kippelen, B., Appl. Phys. Lett. 85 (2004) 5427.
[11] Mayer, A. C., Lloyd, M. T., Herman, D. J., Kasen, T. G., and Malliaras, G. G., Appl. Phys. Lett. 85 (2004) 6272.
[12] Chu, C.-W., Shao, Y., Shrotriya, V., and Yang, Y., Appl. Phys. Lett. 86 (2005) 243506.
[13] Park, S. P., Kim, S. S., Kim, J. H., Whang, C. N., and Im, S., Appl. Phys. Lett. 80 (2002) 2872.
[14] Han, S.-H., Yoo, S., Domercq, B., Kippelen, B., and Levi, D., in preparation.
[15] Pettersson, L. A. A., Roman, L. S., and Inganas, O., J. Appl. Phys. 86 (1999) 487.
[16] Peumans, P., Yakimov, A., and Forrest, S. R., J. Appl. Phys. 93 (2003) 3693.
[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.
[18] Peumans, P. and Forrest, S. R., Appl. Phys. Lett. 79 (2001) 126.
[19] Parthasarathy, G., Burrows, P. E., Khalfin, V., Kozlov, V. G., and Forrest, S. R., Appl. Phys. Lett. 72 (1998) 2138.
[20] The metal source in the deposition system was approximately 1 meter below the substrate.
[21] Salzman, R. F., Xue, J., Rand, B. P., Alexander, A., Thompson, M. E., Forrest, S. R., Org. Electron. 6 (2005) 242.
[22] Shtein, M., Mapel, J., Bensiger, J. B., and Forrest, S. R., Appl. Phys. Lett. 81 (2002) 268.

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