Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE

7/7
Figure 6: Large area flexible solar cell in metal frame. Patterning of the cell structure is realized with
shadow masks.
For improving the reproducibility of the deposition system process control strategies are in evaluation
and testing. The CIGS deposition process was automatised by using computer control with recording
options for the most important process parameters by developing suitable software programs.
Testing of alternative back contact materials
Deposition of alternative materials such as transparent conductive oxides is in progress. Refining of
the deposition conditions should yield stress and crack free layers suitable for depositing high efficiency
CIGS layers. The new solar cell structures would give benefits by the higher reflectivity and
improved chemical stability of the new materials.
National and international collaboration
Some aspects of this project benefit from the collaboration with FLISOM AG, an ETHZ spin-off company
and other national and European projects in the thin film physics group.
Evaluation 2007 and Outlook 2008
The investigation of the custom build evaporators and in-line deposition equipment has shown promising
results in terms of the structural layer homogeneity, namely compositional and thickness distribution
over the processable deposition width. Nevertheless, process reliability and control needs further
improvement for ensuring a high efficiency on large area substrates. Possible control tools are under
evaluation and will be tested in then next process period. Further the deposition parameters need
optimization for reaching envisaged efficiencies beyond 10%. The chemical bath deposition step has
successfully been adapted to large areas by using a new set-up design. More routine work is required
fine-tune the thin layer deposition free of particulate by-products. First tests with the deposition of alternative
back contact materials have shown promising results.
In 2008 activities will focus on improving the overall solar cell processing for higher efficiencies and
gain experience for continuous in-line processing.
Large Area Flexible CIGS, D. Brémaud, ETHZ Seite 81 von 288