Current Photovoltaic Research

Korea Photovoltaic Society (한국태양광발전학회)
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A Comparative Study of Two Different SnO2:F-coated Glass Substrates for CdTe Solar Cells

  • Cha, Eun Seok (Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Ko, Young Min (Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Choi, Yong Woo (Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Park, Gyu Chan (Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Ahn, Byung Tae (Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology)
  • Received : 2017.01.24
  • Accepted : 2017.02.09
  • Published : 2017.03.31
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Abstract

Two different fluorine-doped tin oxide (FTO)-coated glass substrates were investigated to find better suitability for CdTe solar cells. Substrate A consisted of FTO (300 nm)/$SiO_2$ (24 nm)/intrinsic $SnO_2$ (30 nm)/borosilicate glass (2.2 mm), and substrate B consisted of FTO (700 nm)/intrinsic $SnO_2$ (30nm)/borosilicate glass (1.8 mm). The overall thickness of the FTO/glass substrates was about 2.5 mm. The total light transmittance of substrate B was much higher than that of substrate A throughout the whole spectral region, even though the thickness of the FTO in substrate B was twice larger than that of the FTO in the substrate A. The short-circuit current greatly increased in substrate B and the external quantum efficiency (EQE) increased over the whole wavelength range. This study shows that the diffuse optical transmittance played a key role in the large EQE value in the blue wavelength region, and the direct transmittance played a key role in the large EQE value in the red wavelength region. The higher transmittance is due to the rough surface generated by the thicker FTO on glass. The conversion efficiency of the CdTe solar cell increased from 12.4 to 15.1% in combination of rough FTO substrate and Cu solution back contact.

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References

  1. M. A. Green, K. Emery, Y. Hishikawa, W. Warta, E. D. Dunlop, Solar cell efficiency tables (Ver. 45), Prog. Photovolt. Res. Appl., 23, 1 (2015). https://doi.org/10.1002/pip.2573
  2. D. M. Meysing, C. A. Wolden, M. M. Griffith, H. Mahabaduge, J. Pankew, M. O. Reese, J. M. Burst, W. L. Rance, T. M. Barnes, Properties of reactively sputtered oxygenated cadmium sulfide (CdS:O) and their impact on CdTe solar cell performance, J. Vacuum Sci. Technol. A, 33, 021203 (2015).
  3. X. Wu, J. Zhou, A. Duda, J. C. Keane, T. A. Gessert, Y. Yan, R. Noufi, 13.9%-efficient CdTe polycrystalline thin-film solar cells with an infrared transmission of similar to 50%, Prog. Photovol., 14, 471 (2006). https://doi.org/10.1002/pip.664
  4. K. Jeyadheepan, M. Thamilselvan, K. Kim, J. Yi, C. Sanjeeviraja, Optoelectronic properties of R-F magnetron sputtered Cadmium Tin Oxide ($Cd_2SnO_4$) thin films for CdS/CdTe thin film solar cell applications, J. Alloys Compounds, 620, 185 (2015). https://doi.org/10.1016/j.jallcom.2014.09.056
  5. M. S. Kim, L. Larina, J. H. Yun, B. T. Ahn, Fabrication of CdTe solar cell using an In(OOH,S)/CdS double layer as a heterojunction counterpart, Curr. Appl. Phys. 9, 455 (2009). https://doi.org/10.1016/j.cap.2008.04.003
  6. E. S. Cha, Y. M. Ko, S. C. Kim, B. T. Ahn, Short-circuit current improvement in CdTe solar cells by combining a ZnO buffer and a solution back contact, Curr. Appl. Phys. 17, 47-54 (2017). https://doi.org/10.1016/j.cap.2016.10.014
  7. C.J. D. Godines, C. G. T. Castanedo, CGT, R. C. Perez, G. T. Delgado, O. Z. Angel, Transparent conductive thin films of $Cd_2SnO_4$ obtained by the sol-gel technique and their use in a solar cell made with CdTe, Sol. Ener. Mater. Sol. Cel., 128, 150-155, 2014. https://doi.org/10.1016/j.solmat.2014.05.023
  8. S. Vatavu, C. Rotaru, V. Fedorov, T. A. Stein, M. Caraman, I. Evtodiev, C. Kelch, M. Kirsch, P. Chetrus, P. Gasin, ; Lux-Steiner, MC (Lux-Steiner, Martha Ch.) ; Rusu, M (Rusu, Marin) A comparative study of (ZnO, $In_2O_3$: $SnO_2$, $SnO_2$)/CdS/CdTe/(Cu/)Ni heterojunctions, Thin Solid Films, 535, 244-248 (2013). https://doi.org/10.1016/j.tsf.2012.11.105
  9. J. Perrenoud, L. Kranz, S. Buecheler, F. Pianezzi, A. N. Tiwari, Thin Solid Films, The use of Al-doped ZnO as transparent conductive oxide for CdS/CdTe solar cells, 519, 7444 (2011). https://doi.org/10.1016/j.tsf.2010.12.234
  10. H. D. Kim, D.S. Kim, Kurn, Cgo, B. T. Ahn, H. B. Im, Photovoltaic Properties of Sintered CdS/CdTe solar cells with an indium-tin-oxide electrode, J. Electrochem. Soc., 141, 3572 (1994). https://doi.org/10.1149/1.2059371
  11. J. Britt, C. Ferekides, Appl. Phys. Lett., Thin-film CdS/CdTe solar cell with 15.8% efficiency,62, 2851 (1993). https://doi.org/10.1063/1.109629
  12. D. Grecu, A. D. Compaan, D. Young, U. Jayamaha and D. H. Rose, Photoluminescence of Cu-doped CdTe and related stability issues in CdS/CdTe solar cells, J. Appl. Phys. 88, 2490 (2000). https://doi.org/10.1063/1.1287414
  13. I. Visoly-Fisher, K.D. Dobson, J. Nair, E. Bezalel, G. Hodes, D. Cahen, Factors affecting the stability of CdTe/CdS solar cells deduced from stress tests at elevated temperature, Adv. Funct. Mater. 13 (2003) 289 (2003). https://doi.org/10.1002/adfm.200304259
  14. B. A. Korevaar, R. Shuba, A. Yakimov, H. Cao, J. C. Rojo, T. R. Tolliver, Initial and degraded performance of thin film CdTe solar cell devices as a function of copper at the back contact, Thin Solid Films, 519, 7160 (2011). https://doi.org/10.1016/j.tsf.2011.01.134
  15. H. C. Chou, A. Rohatgi, E. W. Thomas, S. Kamra, A. K. Bhat, Effects of Cu on CdTe/CdS Heterojunction Solar Cells with Au/Cu Contacts, J. Electrochem. Soc., 142, 254 (1995). https://doi.org/10.1149/1.2043891
  16. B. T. Ahn, J. H. Yun, E. S. Cha, K. C. Park, Understanding the junction degradation mechanism in CdS/CdTe solar cells using a Cd-deficient CdTe layer, Curr. Appl. Phys., 12, 174 (2012). https://doi.org/10.1016/j.cap.2011.05.031
  17. V. Evani, M. Khan; S. Collins, V. Palekis, P. Bane, D. Morel, C. Ferekides, Effect of Cu and Cl on EVT-CdTe solar cells, Proc. 42nd Photovolt. Special. Conf. (PVSC), 1-5, New Orleans (2015).
  18. S. Demtsu and J. Sites, D. Albin, Role of Copper in the Performance of CdS/CdTe Solar Cells, Proc. 4th World Conf. Photovolt. Energy Conv. (WCPEC-4), 523-529, Waikoloa (2006).