Influence of Cathode Work Functions on the Photovoltaic Properties of MEH-PPV: TiO₂ Bulk Heterojunction Solar Cell

Abstract:

Bulk heterojunction solar cell has received significant attention over the past decade due to low cost power generation and the potential to develop a clean renewable energy source [. We investigated the effect of different type of metal cathodes on the power conversion efficiency of bulk heterojunction solar cell based on a blend of conjugated polymer poly [2-methoxy 5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) with titanium dioxide (TiO₂). In this case of study, Aluminum (Al) and gold (Au) has been chosen as the metal cathode due to the difference of work function and their wide application in hybrid solar cell. We show that the choice of metal cathode plays a role in determining overall device efficiency through their impact on short-circuit current, open circuit voltage and fill factor due to the influence of work function. It is found that the device employing Al metal cathode which has low work function is showing a comparable performance to the Au metal electrode with fill factor of over 20 % and a power conversion efficiency of 3.3x10^-3 %. Overall it is demonstrated that the matching between the work function of the cathode and photoactive layer MEH-PPV: TiO₂ is the most important factor towards best bulk heterojunction solar cell performance.

• Periodical: Advanced Materials Research (Volume 832)
• Pages: 399-403
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.832.399
• Online since: November 2013
• Authors: Fazlinashatul Suhaidah Zahid, Puteri Sarah Mohamad Saad, Musa Mohamed Zahidi, Mohamad Rusop Mahmood
• Keywords: MEH-PPV, Metal Cathode, Solar Cell, TiO₂, Work Function

References

[1] A. C. Mayer, S. R. Scully, B. E. Hardin, M. W. Rowell, and M. D. McGehee, Polymer-based solar cells, Materials Today.10 (2007) 28-33.

DOI: 10.1016/s1369-7021(07)70276-6

[2] W. Cai, X. Gong, and Y. Cao, Polymer solar cells: Recent development and possible routes for improvement in the performance, Solar Energy Materials and Solar Cells.94 (2010) 114-127.

DOI: 10.1016/j.solmat.2009.10.005

[3] P. M. Sirimanne, T. Shirata, L. Damodare, Y. Hayashi, T. Soga, and T. Jimbo, An approach for utilization of organic polymer as a sensitizer in solid-state cells, Solar Energy Materials and Solar Cells. 77 (2003) 15-24.

DOI: 10.1016/s0927-0248(02)00241-6

[4] C. C. Oey, A. B. Djurisic, H. Wang, K. K. Y. Man, W. K. Chan, M. H. Xie, Y. H. Leung, A. Pandey, J. M. Nunzi, and P. C. Chui, Polymer TiO2 solar cells: TiO2 interconnected network for improved cell performance, Nanotechnology. 17 (2006) 706.

DOI: 10.1088/0957-4484/17/3/015

[5] V. D. Mihailetchi, H. X. Xie, B. de Boer, L. J. A. Koster, and P. W. M. Blom, Charge Transport and Photocurrent Generation in Poly(3-hexylthiophene): Methanofullerene Bulk-Heterojunction Solar Cells, Advanced Functional Materials.16 (2006) 699-708.

DOI: 10.1002/adfm.200500420

[6] M. Z. Musa, M. F. Malek, M. H. Mamat, U. M. Noor, N. A. Rashied, and M. Rusop, Effects Of Spin Coating Speed On Nanostructured Titanium Dioxide (TiO2) Thin Films Properties, American Institute of Physics, 1341 (2011) 33-36.

DOI: 10.1109/escinano.2010.5701016

[7] A. K. Pandey, P. E. Shaw, I. D. W. Samuel, and J.-M. Nunzi, Effect of metal cathode reflectance on the exciton-dissociation efficiency in heterojunction organic solar cells, Applied Physics Letters. 94 (2009) 103303-3.

DOI: 10.1063/1.3098472

[8] T.Soga, Nanostructured Materials for Solar Energy Conversion, Elsevier, (2006) 282.

[9] K.Schulze, B.Maenning, K.Leo, Y.Tomita, C.May, J.Hupkes, E.Brier, and P.Bauerle, Organic solar cells based on indium tin oxide and aluminium doped zinc oxide anode, Appl.Phys.Lett. 91 (2007) 1-3.

DOI: 10.1063/1.2771050

[10] C. J. Brabec, A. Cravino, D. Meissner, N. S. Sariciftci, M. T. Rispens, L. Sanchez, J. C. Hummelen, and T. Fromherz, The influence of materials work function on the open circuit voltage of plastic solar cells, Thin Solid Films.403-404 (2002) 368-372.

DOI: 10.1016/s0040-6090(01)01586-3

[11] S. C. Price, A. C. Stuart, L. Yang, H. Zhou, and W. You,Fluorine Substituted Conjugated Polymer of Medium Band Gap Yields 7% Efficiency in Polymer-Fullerene Solar Cells, Journal of the American Chemical Society.133 (2011) 4625-4631.

DOI: 10.1021/ja1112595

[12] L. Shen, G. Zhu, W. Guo, C. Tao, X. Zhang, C. Liu, W. Chen, S. Ruan, and Z. Zhong, Performance improvement of TiO2/P3HT solar cells using CuPc as a sensitizer, Applied Physics Letter. 92 (2008) 073307-073309.

DOI: 10.1063/1.2884270

[13] Z. Tsung-Wei, L. Yun-Yue, L. Hsi-Hsing, C. Chun-Wei, C. Cheng-Hsuan, L. Sz-Chian, H. Hong-Yun, and S. Wei-Fang, A large interconnecting network within hybrid MEH-PPV/TiO2 nanorod photovoltaic devices, Nanotechnology.17 (2006) 5387.

DOI: 10.1088/0957-4484/17/21/017

[14] J. S. Salafsky, Exciton dissociation, charge transport, and recombination in ultrathin, conjugated polymer-TiO2 nanocrystal intermixed composites, Physical Review B.59 (1999) 10885-10894.

DOI: 10.1103/physrevb.59.10885

[15] P. Schilinsky, C.Waldauf, J. Hauch, and C. J. Brabec, Simulation of light intensity dependent current characteristics of polymer solar cells, Journal of Applied Physics. 95 (2004) 2816 -2819.

DOI: 10.1063/1.1646435