Optical Properties and Analysis of OJL Model’s Electronic inter-band Transition Parameters of TiO2 Films
Titanium dioxide is a wide band gap semiconductor responsible for the bright white appearance in most substances. This material has many unique properties due to its extra-ordinary chemical stability. TiO2 has a conduction band that closely matches the excited energy level of organic dyes hence it is used in fabrication of photo-anode electrode of dye sensitized solar cell. However, the optical properties and the density of states of TiO2 thin films determine the performance of dye sensitized solar cell fabricated from TiO2 photo-anode electrode. For this reason, the purpose of this study was to investigate the optical properties and the OJL electronic inter-band transition analysis of TiO2 nanoparticle thin films. Under the OJL model, the expressions of density of states were specified for the optical transition from the valence band to the conduction band. The TiO2 nanoparticles were prepared using sol-gel and hydrothermal methods and deposited on a conductive glass substrate by screen printing and spray pyrolysis techniques. SEM analysis revealed that TiO2 nanoparticles were spongy and had unevenly sphere-shaped profile while TiO2 nanotubes had a skein-like morphology with abundant number of nanotubes intertwined together. This study showed that TiO2 thin films have both direct and indirect band-gaps. The OJL Gap energy (E0) values were observed to be between 30273.2356 and 31072.0000 wavenumbers which translated to band-gap energies between 3.744 and 3.843 eV. From these findings showed that TiO2 films prepared could be used in the fabrication of high performing dye-sensitized solar cell.
1. O’Regan, B., & Grätzel, M. (1991). A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films. Nature, 353(6346), 737–740.
2. Martirosyan, A., & Schneider, Y.-J. (2014). Engineered Nanomaterials in Food: Implications for Food Safety and Consumer Health. International Journal of Environmental Research and Public Health, 11(6), 5720–5750.
3. Zhang, Y., Leu, Y.-R., Aitken, R., & Riediker, M. (2015). Inventory of Engineered Nanoparticle-Containing Consumer Products Available in the Singapore Retail Market and Likelihood of Release into the Aquatic Environment. International Journal of Environmental Research and Public Health, 12(8), 8717–8743.
4. Bedikyan, L., Zakhariev, S. & Zakharieva, M. (2013). Titanium Dioxide Thin Films: Preparation and Optical Properties. Journal of Chemical Technology and Metallurgy, 48(6), 555–558.
5. Mawyin, J. (2009). Characterization of Anthocyanin Based Dye-Sensitized Organic Solar Cells (DSSC) and Modifications Based on Bio-Inspired Ion Mobility Improvements (Doctoral thesis). Retrieved from http://adsabs.harvard.edu/abs/2009PhDT.......291M
6. Malekshahi Byranvand, M., Nemati Kharat, A., & Fatholahi, L. (2012). Influence of nanostructured TiO2 film thickness on photo-electrode structure and performance of flexible Dye-Sensitized Solar Cells. Journal of Nanostructures, 2, 327–332.
7. Atif, M., Farooq, W., Fatehmulla, A., Aslam, M., & Ali, S. (2015). Photovoltaic and Impedance Spectroscopy Study of Screen-Printed TiO2 Based CdS Quantum Dot Sensitized Solar Cells. Materials, 8(1), 355–367.
8. Viana, M. M., Mohallem, T. D. S., Nascimento, G. L. T., & Mohallem, N. D. S. (2006). Nanocrystalline titanium oxide thin films prepared by sol-gel process. Brazilian Journal of Physics, 36(3b), 1081–1083.
9. Sima, C., Waldhauser, W., Lackner, J., Kahn, M., Nicolae, I., Viespe, C., Grigoriu, C., & Manea, A. (2007). Properties of TiO2 thin films deposited by RF magnetron sputtering. Journal of Optoelectronics and Advanced Materials, 9, 1446–1449.
10. Mathur, S., & Kuhn, P. (2006). CVD of titanium oxide coatings: Comparative evaluation of thermal and plasma assisted processes. Surface and Coatings Technology, 201(3-4), 807–814.
11. Hanaor, D., Michelazzi, M., Veronesi, P., Leonelli, C., Romagnoli, M., & Sorrell, C. (2011). Anodic aqueous electrophoretic deposition of titanium dioxide using carboxylic acids as dispersing agents. Journal of the European Ceramic Society, 31(6), 1041–1047.
12. Li, H., Liu, H., Fu, A., Wu, G., Xu, M., Pang, G., … Zhao, X. (2016). Synthesis and Characterization of N-Doped Porous TiO2 Hollow Spheres and Their Photocatalytic and Optical Properties. Materials, 9(10), 849.
13. Mosiori, C. O., Maera, J., Shikambe, R., … Magare, R. (2017). Electrical Behavior of Cd0.3Zn1.1x S0.7 Thin Films for Non-Heat Light Emitting Diodes. Path of Science, 3(6), 2.8–2.16.
14. Gopinadhan, K., Kashyap, S. C., Pandya, D. K., & Chaudhary, S. (2007). High temperature ferromagnetism in Mn-doped SnO2 nanocrystalline thin films. Journal of Applied Physics, 102(11), 113513.
15. Kasuga, T., Hiramatsu, M., Hoson, A., Sekino, T., & Niihara, K. (1999). Titania nanotubes prepared by chemical processing. Advanced Materials, 11, 1307–1311.
16. W. Theiss. (n. d.). Thin film analyis with SCOUT. Retrieved June 1, 2018, from http://www.mtheiss.com/?c=2&content=applications_scout
17. Liu, X., Guo, M., Cao, J., Lin, J., Tsang, Y., Chen, X., & Huang, H. (2014). Large-diameter titanium dioxide nanotube arrays as a scattering layer for high-efficiency dye-sensitized solar cell. Nanoscale Research Letters, 9(1), 362.
18. Shariffudin, S. S., Salina, M., Herman, S. H., & Rusop, M. (2012). Effect of Film Thickness on Structural, Electrical, and Optical Properties of Sol-Gel Deposited Layer-by-layer ZnO Nanoparticles. Transactions on Electrical and Electronic Materials, 13(2), 102–105.
19. Outemzabet, R., Bouras, N., & Kesri, N. (2007). Microstructure and physical properties of nanofaceted antimony doped tin oxide thin films deposited by chemical vapor deposition on different substrates. Thin Solid Films, 515(16), 6518–6520.
20. Solieman, A. S., Hafiz, M. M., Abu-Sehly, A. A., & Alfaqeer, A. A. (2014). Dependence of optical properties on the thickness of amorphous Ge30Se70 thin films. Journal of Taibah University for Science, 8(3), 282–288.
21. Ziabari, A. A., & Ghodsi, F. E. (2012). Surface morphology and optoelectronic studies of sol–gel derived nanostructured CdO thin films: heat treatment effect. Journal of Materials Science: Materials in Electronics, 23(9), 1628–1639.
22. Ghrairi, N., & Bouaicha, M. (2012). Structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique. Nanoscale Research Letters, 7(1), 357.
23. Ahmadi, K., Abdolahzadeh Ziabari, A., Mirabbaszadeh, K., & Ahmadi, S. (2015). Synthesis of TiO2 nanotube array thin films and determination of the optical constants using transmittance data. Superlattices and Microstructures, 77, 25–34.
24. Janitabar-Darzi, S., Mahjoub, A. R., & Nilchi, A. (2009). Investigation of structural, optical and photocatalytic properties of mesoporous TiO2 thin film synthesized by sol–gel templating technique. Physica E: Low-Dimensional Systems and Nanostructures, 42(2), 176–181.
25. Satoh, N., Nakashima, T., Kamikura, K., & Yamamoto, K. (2008). Quantum size effect in TiO2 nanoparticles prepared by finely controlled metal assembly on dendrimer templates. Nature Nanotechnology, 3(2), 106–111.
26. Huang, F. (2010). Titanium Dioxide Nanomaterials: Basics and Design, Synthesis and Applications in Solar Energy Utilization Techniques. Solar Collectors and Panels, Theory and Applications.
27. Gordijn, A., Löffler, J., Arnoldbik, W. M., Tichelaar, F. D., Rath, J. K., & Schropp, R. E. I. (2005). Thickness determination of thin (∼20 nm) microcrystalline silicon layers. Solar Energy Materials and Solar Cells, 87(1-4), 445–455.
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