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Title:
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PROCIS : product identification, pilot plant design and market potential evaluation for copper indium disulphide (CuInS2) on copper tape substrates: publishable report
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Author(s):
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Wienke, J.A.; Winkler, M.; Burgelman, M.; Vleuten, P. van der
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Published by:
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Publication date:
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ECN
Solar Energy
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1-5-2002
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ECN report number:
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Document type:
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ECN-C--02-052
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ECN publication
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Number of pages:
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Full text:
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11
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Download PDF
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Abstract:
The new, innovative IST-technology for copper indium disulphide (CuInS2)solar cells on copper tapes (CISCuT) is a cost-effective series of consecutive
roll-to-roll processes. One major feature of this technology is the
multifunctionality of the copper tape (1 cm in width), serving as mechanical
carrier, source for in-line CIS-formation and back contact of the solar
cell, another is the potential to make flexible cells and modules.
During the PROCIS project, the CISCuT technology has been further developed
to a baseline for CuInS2 solar cell fabrication. In this sense, a major
project effort has been the up scaling from the manually produced 2
mm2 dot cells at the beginning to large area tape (up to 10 cm in length).
For the definition of the baseline equipment a comprehensive characterisation
and modelling of CuInS2 material has been carried out. It was found
that with standard processing conditions (a copper band speed of 3-4
cm/s and a temperature of 550 °C for the sulphurisation step) CuInS2
with an internal p-n junction is produced. This material consists of
various Cu-In-S phases with the result that the photoelectrical properties
of ?as-grown? CISCuT material differ from conventional CIS layers. Therefore,
it requires different charge collecting layers with fortunately no need
for the usually applied (toxic) CdS layer. The Cu/CuInS2/CuI/ZnO:Al
configuration was selected as most promising in two aspects: the deposition
equipment needed for the involved collecting layers could be integrated
in the roll-to-roll technology and, with this cell concept the highest
cell efficiency ( = 5.4 % on 400 mm2) is achieved.
In parallel, a simpler Cu/CuInS2/CuI/metal grid configuration was investigated.
In this case, the metal grid replaces the ZnO:Al window layer. However,
the up scaling of this cell concept is still in its infancy.
Intensive research has been done to find suitable contacting and interconnection
technologies. As a result, roof-tile integrated modules with maximum
dimensions of (10x20) cm2 and 10 V output have been produced. The favourable
flexibility of the copper tape material could be retained in the module
by using specific contacting/lamination methods.
Preliminary stability and climate tests have been carried out on CISCuT
devices. The results indicate that laminated devices are stable under
continuous illumination at room temperature. Humidity in combination
with high temperature (85 %, 85 °C) however resulted in delamination
and cell corrosion. Therefore, improvement in lamination technology
is urgently needed.
A good understanding of device physics could be obtained by extension
of standard measurement techniques with Light Beam Induced Current (LBIC)
Spectroscopy, Secondary Ion Mass Spectroscopy (SIMS), Parallel Resistance
Analysis by Mapping of Potential (PRAMP) and thermography measurements.
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