Development of reproducible ultra-thin CuIn(Ga)Se2 absorber material for solar cell production.
CuIn(Ga)(S,Se)2 (CI(G)S) is one of the most common thin film (TF) photovoltaic (PV) solar cells commercially available today. One of the main advantages these TFPV technologies have over the silicon solar cells is that, due to their direct band gap, their overall thickness can be lowered down to around 1 µm, compared to the much thicker (~100 µm) silicon-based PV technology. This is not only a considerable reduction of the amount of material used but also opens the door to a wide variety of applications, such as the deposition on flexible substrates or building integration, due to the relative flexibility of the thinner solar cells.
Nevertheless, the market share of the TFPV technologies stays very low (~5% of combined presence). This is due to a number of different factors, such as the fact that silicon is very earth abundant and thus, even though the production of the Si-cells requires a lot more material, they can be produced on a very large scale, at a very low cost. Another problem that the TFPV sector is facing is the relatively large discrepancy between the record cell efficiencies that are achievable in a laboratory, up to 23.35% as presented by Solar Frontier, and their achievable module efficiency of around 16%. The difference in the case of Si-PV is on average lower, which still makes Si-PV interesting on the module level today.
The possible origin of the discrepancy between record cell and record module in the case of TFPV can be due to several reasons. A good first candidate for review is the difficulty to provide a reproducible and perfectly controllable process for the industry to use, allowing to produce perfectly homogeneous modules. Increasing the reproducibility of the CIGS processing method, would lead to more homogeneously efficient module, and ultimately to a better overall conversion efficiency of the module.
The aim of this internship is to work on the development of a reproducible and homogeneous baseline methodology for the doping of ultra-thin (500nm) CI(G)S absorber material with alkali atoms. The process will have to be as simple and reproducible as possible to stay compatible with industry and their objective of cost-effective mass production. The task of the accepted student will be to investigate the different possibilities, test them, and select the most suited one based on the evaluation of relevant experimentally determinable parameters.
Thierry Kohl, PhD Candidate at University of Hasselt/imec
Host University: University of Hasselt, Belgium
Promoter: Prof. Bart Vermang
Internship Location: EnergyVille 2, Thor Park 8320, 3600 Genk
Type of project: Thesis, Combination of internship and thesis
Duration: 6 months minimum
Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science
Required background: Chemistry/Chemical Engineering, Electrotechnics/Electrical Engineering, Energy, Materials Engineering, Physics
Supervising scientist(s): For further information or for application, please contact: Thierry Kohl (Thierry.Kohl@imec.be)
Imec allowance will be provided for students studying at a non-Belgian university.