What are CdTe and CIGS Solar Cells?
CdTe thin film solar cells are becoming increasingly popular within commercial photovoltaic production due to their low fabrication cost and rising efficiency. The material is very well suited for solar cell applications as it has a high optical absorption coefficient in the visible (high intensity) portion of the solar spectrum. Furthermore it has a band gap of around 1.5 eV, which is close to the optimum for a terrestrial solar cell. CdTe films are polycrystalline, and can be fabricated by physical vapour deposition, sputtering and electrodepostion. The resulting thin film layers show good chemical stability and module efficiencies greater than 11% have been achieved.
CIGS solar cells have the highest production of any thin film photovoltaic technology. Their conversion efficiency on a glass substrate is now approaching 20%. Advances in fabrication technology mean that they are approaching market values for carbon based energy production. Recent developments in the field of CIGS has seen a move towards flexible devices, with polyamide or metal foil substrates. Their flexible nature, resistance to solar radiation and high specific power has led CIGS collar cells to becoming increasingly used for space applications. GIGS solar cells have a very high absorption coefficient at their band gap of 1.5 eV, resulting in a very strong absorption of the solar spectrum.
What are the challenges for CdTe and CIGS Solar Cells?
For CdTe to continue to compete successfully with other photovoltaic technologies, an increase in module efficiency is required. This could be achieved by improving the electronic properties of the devices, including increasing the open circuit voltage and controlling recombination in the absorbing layer.
A key challenge for the increased uptake of CIGS solar cells is to develop a deposition process onto a flexible substrate at lower temperatures to allow for a roll to roll fabrication process. Current deposition methods including vacuum based coevaporation and sputtering are required for CIGS fabrication. Therefore the development of less complex deposition methods will significantly increase the uptake of CIGS solar cells.
How are these challenges being addressed by SISER researchers?
Heriot-Watt University is working on the development of processing technologies for thin film solar cells. Their recent work on CIGS includes developing low cost processes for incorporating copper into indium gallium selenide layers. In addition, they are carrying out work on the application of CdTe bifacial thin film solar cells for building integrated photovoltaics (BIPV), including integrated PV double glazing.
SISER researchers with interest in this area are: Prof. Robert Martin.
Full details of all SISER researchers are found on the SISER People Page.
Publications
Preparation of Cu(In,Ga)Se-2 thin film solar cells by two-stage selenization processes using N-2 gas. Solar Energy Materials and Solar Cells 89(2-3):129-137, 2005. Structural properties of Cu(In,Ga)Se-2 thin films prepared from chemically processed precursor layers. Thin Solid Films 517(7):2235-2239, 2009. P Liska, K R Thampi, M Gratzel, D Bremaud, D Rudmann, H M Upadhyaya and A N Tiwari. Nanocrystalline dye-sensitized solar cell/copper indium gallium selenide thin-film tandem showing greater than 15% conversion efficiency. Applied Physics Letters 88(20), 2006. Structural, photoluminescent and electrical properties of CdTe films with different compositions fabricated by CMBD. Solar Energy 83(1):90-93, 2009. Fabrication and characterisation of Cu(In,Ga)Se-2 solar cells on polyimide. Thin Solid Films 519(21):7264-7267, 2011.
BibTeX@article{Preparation of Cu(In,
ga)se-2 thin film solar cells by two-stage selenization processes using n-2 gas, author = "Gremenok, V. F. and Zaretskaya, E. P. and Zalesski, V. B. and Bente, K. and Schmitz, W. and Martin, R. W. and Moller, H.",
title = "Preparation of Cu(In,Ga)Se-2 thin film solar cells by two-stage selenization processes using N-2 gas",
journal = "Solar Energy Materials and Solar Cells",
volume = 89,
number = "2-3",
pages = "129-137",
note = "Times Cited: 12 martin, rob/A-7127-2010 martin, rob/0000-0002-6119-764X Eurosun 2004 Conference Jun 20-23, 2004 Freiburg, GERMANY 13",
year = 2005
}
BibTeX@article{Structural properties of Cu(In,
ga)se-2 thin films prepared from chemically processed precursor layers, author = "Hibberd, C. J. and Ganchev, M. and Kaelin, M. and Dann, S. E. and Bilger, G. and Upadhyaya, H. U. and Tiwari, A. N.",
title = "Structural properties of Cu(In,Ga)Se-2 thin films prepared from chemically processed precursor layers",
journal = "Thin Solid Films",
volume = 517,
number = 7,
pages = "2235-2239",
note = "Times Cited: 5 Symposium on Thin Film Chalcogenide Photovoltaic Materials held at the EMRS 2008 Spring Conference May 26-30, 2008 Strasbourg, FRANCE European Mat Res Soc 5",
year = 2009
}
BibTeX@article{Nanocrystalline dye-sensitized solar cell/copper indium gallium selenide thin-film tandem showing greater than 15% conversion efficiency,
author = "Liska, P. and Thampi, K. R. and Gratzel, M. and Bremaud, D. and Rudmann, D. and Upadhyaya, H. M. and Tiwari, A. N.",
title = "Nanocrystalline dye-sensitized solar cell/copper indium gallium selenide thin-film tandem showing greater than 15% conversion efficiency",
journal = "Applied Physics Letters",
volume = 88,
number = 20,
note = "Times Cited: 51 Graetzel, Michael/G-4870-2011; Balasingam, Suresh Kannan/E-1631-2013 Balasingam, Suresh Kannan/0000-0003-3774-4209 56",
year = 2006
}
BibTeX@article{Structural,
photoluminescent and electrical properties of cdte films with different compositions fabricated by cmbd, author = "Razykov, T. M. and Contreras-Puente, G. and Chornokur, G. C. and Dybjec, M. and Emirov, Yu and Ergashev, B. and Ferekides, C. S. and Hubbimov, A. and Ikramov, B. and Kouchkarov, K. M. and Mathew, X. and Morel, D. and Ostapenko, S. and Sanchez-Meza, E. and Stefanakos, E. and Upadhyaya, H. M. and Vigil-Galan, O. and Vorobiev, Yu V.",
title = "Structural, photoluminescent and electrical properties of CdTe films with different compositions fabricated by CMBD",
journal = "Solar Energy",
volume = 83,
number = 1,
pages = "90-93",
note = "Times Cited: 15 16",
year = 2009
}
BibTeX@article{Fabrication and characterisation of Cu(In,
ga)se-2 solar cells on polyimide, author = "Zachmann, H. and Puttnins, S. and Yakushev, M. V. and Luckert, F. and Martin, R. W. and Karotki, A. V. and Gremenok, V. F. and Mudryi, A. V.",
title = "Fabrication and characterisation of Cu(In,Ga)Se-2 solar cells on polyimide",
journal = "Thin Solid Films",
volume = 519,
number = 21,
pages = "7264-7267",
note = "Times Cited: 1 martin, rob/A-7127-2010 martin, rob/0000-0002-6119-764X Si 1",
year = 2011
}
