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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 50, Iss. 19 — Jul. 1, 2011
  • pp: 3296–3302

Spectrally selective reflector surfaces for heat reduction in concentrator solar cells: modeling and applications of TiO 2 :Nb-based thin films

Christopher M. Maghanga, Gunnar A. Niklasson, Claes G. Granqvist, and Mghendi Mwamburi  »View Author Affiliations

Applied Optics, Vol. 50, Issue 19, pp. 3296-3302 (2011)

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The energy conversion efficiency of a conventional p n junction solar cell decreases as the temperature increases, and this may eventually lead to failures in the photovoltaic system, especially if it uses concentrated solar radiation. In this work, we show that spectrally selective reflector (SSR) surfaces can be important for reducing the heat buildup on passively cooled solar cells. We outline a computational scheme for optimizing DC magnetron-sputtered TiO 2 :Nb-based SSRs tailored for silicon solar cells and find good agreement of the reflectance with an experimental realization of the optimal SSR. A figure of merit for SSRs has also been derived and applied to the experimental data.

© 2011 Optical Society of America

OCIS Codes
(310.3840) Thin films : Materials and process characterization
(310.6860) Thin films : Thin films, optical properties
(310.4165) Thin films : Multilayer design
(310.6188) Thin films : Spectral properties
(310.6805) Thin films : Theory and design
(310.7005) Thin films : Transparent conductive coatings

ToC Category:

Original Manuscript: February 28, 2011
Manuscript Accepted: April 25, 2011
Published: June 29, 2011

Christopher M. Maghanga, Gunnar A. Niklasson, Claes G. Granqvist, and Mghendi Mwamburi, "Spectrally selective reflector surfaces for heat reduction in concentrator solar cells: modeling and applications of TiO2:Nb-based thin films," Appl. Opt. 50, 3296-3302 (2011)

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  1. J. J. Wysocki and P. Rappaport, “Effect of temperature on photovoltaic solar energy conversion,” J. Appl. Phys. 31, 571–578 (1960). [CrossRef]
  2. A. Royne, C. J. Dey, and D. R. Mills, “Cooling of photovoltaic cells under concentrated illumination: a critical review,” Solar Energy Mater. Solar Cells 86, 451–483 (2005). [CrossRef]
  3. C. Min, C. Nuofu, Y. Xiaoli, W. Yu, B. Yiming, and Z. Xingwang, “Thermal analysis and test for single concentrator solar cells,” J. Semiconductors 30, 044011 (2009). [CrossRef]
  4. M. Mwamburi, E. Wäckelgård, and A. Roos, “Preparation and characterisation of solar selective SnOx:F coated aluminium reflector surfaces,” Thin Solid Films 374, 1–9 (2000). [CrossRef]
  5. M. Mwamburi and E. Wäckelgård, “Doped tin oxide coated aluminium solar selective reflector surfaces,” Solar Energy 68, 371–378 (2000). [CrossRef]
  6. M. Mwamburi, E. Wäckelgård, A. Roos, and R. Kivaisi, “Polarization-dependent angular-optical reflectance in solar-selective SnOx:F/Al2O3/Al reflector surfaces,” Appl. Opt. 41, 2428–2434 (2002). [CrossRef] [PubMed]
  7. M. Mwamburi, A. Hoel, and E. Wäckelgård, “Surface morphologies of spectrally selective and polarization-dependent angular optical reflectors of SnOx:F-coated anodized aluminum,” Solar Energy Mater. Solar Cells 84, 381–394 (2004). [CrossRef]
  8. C. M. Maghanga, G. A. Niklasson, C. G. Granqvist, and M. Mwamburi, “Optical modeling of spectrally selective reflectors based on TiO2:Nb transparent conducting oxide films for silicon solar cell applications,” Proc. SPIE 7407F, 74070F (2009). [CrossRef]
  9. C. M. Maghanga, J. Jensen, G. A. Niklasson, C. G. Granqvist, and M. Mwamburi, “Transparent and conducting TiO2:Nb films made by sputter deposition: application to spectrally selective solar reflectors,” Solar Energy Mater. Solar Cells 94, 75–79 (2010). [CrossRef]
  10. M. W. Edenburn, “Active and passive cooling for concentrating photovoltaic arrays,” in Proceedings of the 14th IEEE Photovoltaic Specialists Conference (IEEE, 1980), pp. 771–776.
  11. A. Cheknane, B. Benyoucef, and A. Chaker, “Performance of concentrator solar cells with passive cooling,” Semicond. Sci. Technol. 21, 144–147 (2006). [CrossRef]
  12. S. Jiang, P. Hu, S. Mo, and Z. Chen, “Optical modeling for a two-stage parabolic trough concentrating photovoltaic/thermal system using spectral beam splitting technology,” Solar Energy Mater. Solar Cells 94, 1686–1696 (2010). [CrossRef]
  13. Y. Furubayashi, T. Hitosugi, Y. Yamamoto, K. Inaba, G. Kinoda, Y. Hirose, T. Shimada, and T. Hasegawa, “A transparent metal: Nb-doped anatase TiO2,” Appl. Phys. Lett. 86, 252101 (2005). [CrossRef]
  14. C. M. Maghanga, G. A. Niklasson, and C. G. Granqvist, “Optical properties of sputter deposited transparent and conducting TiO2:Nb films,” Thin Solid Films 518, 1254–1258 (2009). [CrossRef]
  15. M. S. Dabney, M. F. A. M. van Hest, C. W. Teplin, S. P. Arenkiel, J. D. Perkins, and D. S. Ginley, “Pulsed laser deposited Nb doped TiO2 as a transparent conducting oxide,” Thin Solid Films 516, 4133–4138 (2008). [CrossRef]
  16. N. Yamada, T. Hitosugi, J. Kasai, N. L. H. Hoang, S. Nakao, Y. Hirose, T. Shimada, and T. Hasegawa, “Direct growth of transparent conducting Nb-doped anatase TiO2 polycrystalline films on glass,” J. Appl. Phys. 105, 123702 (2009). [CrossRef]
  17. T. Hitosugi, N. Yamada, S. Nakao, Y. Hirose, and T. Hasegawa, “Properties of TiO2-based transparent conducting oxides,” Phys. Status Solidi A 207, 1529–1537 (2010). [CrossRef]
  18. Y. Sato, Y. Sanno, C. Tasaki, N. Oka, T. Kamiyama, and Y. Shigesato, “Electrical and optical properties of Nb-doped TiO2 films deposited by dc magnetron sputtering using slightly reduced Nb-doped TiO2−x ceramic targets,” J. Vac. Sci. Technol. A 28, 851–855 (2010). [CrossRef]
  19. http://rredc.nrel.gov/solar/spectra/am1.5.
  20. D. Meneses-Rodríguez, P. P. Horley, J. González-Hernández, Y. V. Vorobiev, and P. N. Gorley, “Photovoltaic solar cells performance at elevated temperatures,” Solar Energy 78, 243–250 (2005). [CrossRef]
  21. M. Mattei, G. Notton, C. Cristofari, M. Muselli, and P. Poggi, “Calculation of the polycrystalline PV module temperature using a simple method of energy balance,” Renew. Energy 31, 553–567 (2006). [CrossRef]
  22. M. Brogren, P. Nostell, and B. Karlsson, “Optical efficiency of a PV-thermal hybrid CPC module for high latitudes,” Solar Energy 69, 173–185 (2001). [CrossRef]
  23. V. Ondok and J. Musil, “Effect of hydrogen on reactive sputtering of transparent oxide films,” Plasma Processes Polym. 4, S319–S324 (2007). [CrossRef]
  24. J. Musil, P. Baroch, J. Vlček, K. H. Nam, and J. G. Han, “Reactive magnetron sputtering of thin films: present status and trends,” Thin Solid Films 475, 208–218 (2005). [CrossRef]
  25. Z. Knittel, Optics of Thin Films (Wiley, 1976), pp. 40–46.
  26. R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1987), pp. 332–340.
  27. D. Y. Smith, E. Shiles, and M. Inokuti, “The optical properties of metallic aluminum,” in Handbook of Optical Constants of Solids, E.D.Palik, ed. (Academic, 1985), pp. 389–406.
  28. T. S. Eriksson, A. Hjortsberg, G. A. Niklasson, and C. G. Granqvist, “Infrared optical properties of evaporated alumina films,” Appl. Opt. 20, 2742–2746 (1981). [CrossRef] [PubMed]

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