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New technologies for chalcopyrite based solar cells

Objective

Investigation of new technologies for the deposition of absorber films of high quality and with economically viable methods and comparison of different approaches. Improvement of device performance with new structures such as graded absorbers and advanced window materials.
New technologies have been investigated for the deposition of absorber films of high quality involving economically viable methods and comparison of different approaches. Improvements in device performance were monitored with respect to new structures such as graded absorbers and advanced window materials.

The most efficient and promising thin film solar cells are based on chalcopyrite compound absorbers. Previous research on the development of Cu(Ga,In)Se2-based solar cells was continued using various deposition technologies.

A general model for film deposition has been worked out and a new device structure has been developed. Efficiency of 12.8% was achieved in a joint effort for a CuInSe2-CdS-ZnO solar cell.
The most efficient and promising thin film solar cells are based on chalcopyrite compound absorbers. During the previous research program of the European Community successful joint research was carried out on the development of Cu(Ga,In)Se2-based solar cells using various deposition technologies. These activities are continued including also new approaches.

The main tasks of the work program are:

1) Deposition of Cu(In,Ga)Se2
- fabrication of films by annealing of structured elemental layers
- annealing of elemental layers by pulsed laser beam
- electrodeposition of chalcopyrite films in one step or of single elemental layers with subsequent annealing.
- fabrication of chalcopyrite films and heterojunctions by screen printing.
- treatment of metal layers and chalcopyrite compounds in selenium vapour.
- study of Cu(In,Ga)Se2 absorber layers with graded optical bandgap
- electrochemical characterization of Cu(Ga,In)Se2 absorber films.
- structural diagnostics by Raman scattering

2) Fabrication of heterojunction solar cells

- preparation of ZnO thin films as transparent contacts and n- type windows in heterostructures
- surface treatments for the improvement of heterojunction interfaces and grain surfaces.
- study of CuGaSe2-based wide gap cells for tandem structures on transparent substrates.
- investigation of surface and interface properties by surface analysis, mainly XPS.

The main goals are:

- Compare the different fabrication methods in view to performance and criteria for large scale manufacturing.

- Realize high efficiency cells by novel device structures.

- Establish a model for the kinetics of film formation. The different approaches for preparation of Cu(Ga,In)Se2 give the opportunity for careful comparison of compound formation.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITAET STUTTGART
Address
Keplerstrasse 7
70174 Stuttgart
Germany

Participants (4)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
Rue Pierre Et Marie Curie 11
75231 Paris
GENT UNIVERSITY
Belgium
Address
Sint Pietersnieuwstraat 25
9000 Gent
Kungliga Tekniska Högskolan
Sweden
Address
229,Electrum 229
164 40 Stockholm Kista
UNIVERSITY OF NORTHUMBRIA AT NEWCASTLE.
United Kingdom
Address
Ellison Place, Ellison Building
Newcastle Upon Tyne