S. Ilican, Y. caglar and M. Caglar, “Preparation and Characterization of ZnO Thin Films Deposited by the Sol-Gel Spin-Coating Method,” Journal of Optoelectronics and Advanced Materials, Vol. 10, No. 10, 2008, p. 2578.
 D. Raoufi and T. Raoufi, “The Effect of Heat Treatment on the Physical Properties of Sol-Gel Derived ZnO Thin Films,” Applied Surface Science, Vol. 255, No. 11, 2009, pp. 5812-5817.
 M. Smirnov, C. Baban and G. I. Rusu, “Structural and Optical Characteristics of Spin-Coated ZnO Thin Films,” Applied Surface Science, Vol. 256, No. 8, 2010, pp. 24052408.
 Y.-J. Shin, et al., “Enhancement of Photovoltaic Properties of Ti Modified Nanocrystalline ZnO Electrode for Dye-Sensitized Solar Cells,” Bulletin of the Korean Chemical Society, Vol. 26, No. 12, 2005, pp. 1929-1930.
 M. C. Kao, H. Z. Chen and S. L. Young, “Effects of PreAnnealing Temperature of ZnO Thin Films on the Performance of Dye-Sensitized Solar Cells,” Applied Physics A, Vol. 98, No. 3, 2010, pp. 595-599.
 D. B. Menzies, et al., “Modification of Mesoporous TiO2 Electrodes by Surface Treatment with Titanium (IV), Indium (III) and Zirconium (IV) Oxide Precursors,” Nanotechnology, Vol. 18, No. 12, Article ID: 125608.
 S. Wu, et al., “Improvement in Dye-Sensitized Solar Cells Employing TiO2 Electrodes Coated with Al2O3 by Reactive Direct Current Magneton Sputtering,” Journal of Power Sources, Vol. 182, No. 1, 2008, p. 119.
 Y. Liu, et al., “Efficiency Enhancement in Dye-Sensitized Solar Cells by Interfacial Modification of Conducting Glass/Mesoporous TiO2 Using a Novel ZnO Compact Blocking Film,” Journal of Power Sources, Vol. 196, No. 1, 2011, pp. 475-481.
 M. C. Kao, H. Z. Chen and S. L. Young, “Effects of ZnOCoating on the Performance of TiO2 Nanostructured Thin Films for Dye-Sensitized Solar Cells,” Applied Physics A, Vol. 97, No. 2, 2009, pp. 469-474.
 S. S. Kim, J. H. Yum and Y. E. Sung, “Improved Performance of a Dye-Sensitized Solar Cell Using a TiO2/ ZnO/Eosin Y Electrode,” Solar Energy Materials and Solar Cells, Vol. 79, No. 4, 2003, pp. 495-505.
 Y. Song, M. Zheng, L. Ma and W. Shen, “Anisotropic Growth and Formation Mechanism Investigation of 1D ZnO Nanorods in Spin-Coating Sol-Gel Process,” Journal of Nanoscience and Nanotechnology, Vol. 10, No. 1, 2010, pp. 426-432. http://dx.doi.org/10.1166/jnn.2010.1724
 H. Yu, S. Zhang, H. Zhao, G. Will and P. Liu, “An Efficient and Low-Cost TiO2 Compact Layer for Performance Improvement of Dye-Sensitized Solar Cells,” Electrochimica Acta, Vol. 54, No. 4, 2009, pp. 1319-1324.
 S. Wu, et al., “Improvement in Dye-Sensitized Solar Cells with a ZnO-Coated TiO2 Electrode by rf Magnetron Sputtering,” Applied Physics Letters, Vol. 92, No. 12, 2008, Article ID: 122106.
 I. Bedja, P. V. Kama, X. Hua, P. G. Lappin and S. Hotchandani, “Photosensitization of Nanocrystalline ZnO Films by Bis (2,2‘-bipyridine)(2,2‘-bipyridine-4,4‘-dicarboxylic acid) Ruthenium (II),” Langmuir, Vol. 13, No. 8, 1997, pp. 2398-2403. http://dx.doi.org/10.1021/la9620115
 A. Umar, A. A. Alharbi, P. Singh and S. A. Sayari, “Growth of Aligned Hexagonal ZnO Nanorods on FTO Substrate for Dye-Sensitized Solar Cells (DSSCs) Application,” Journal of Nanoscience and Nanotechnology, Vol. 11, No. 4, 2011, pp. 3560-3564.