FLEXIBLE Cu In,Ga Se2 THIN FILM SOLAR CELLS FOR SPACE APPLICATIONS RECENT RESULTS FROM A GERMAN JOINT PROJECT PIPV2

Since 2007 a German consortium of academic and industrial partners develops an extremely light and flexible Cu(In,Ga)Se2 (CIGSe) thin film solar cell technology for space applications. The combination with a light support structure and an appropriate interconnection technology enables the construction of a solar generator with previously unmatched specific power (W/kg). This can be attractive as power supply for large platforms in space and is also compatible with alternative, flexible large area applications. The idea of the project is to utilize a solar cell technology, which - in comparison to the highly efficient, multi-junction III-V technology - is cheap and can be fabricated using manufacturing facilities for the terrestrial technology. Project activities encompass topics as fundamental as CIGSe thin film growth, individual aspects of single device components and also device interconnection, together with a corresponding support structure development. So far a maximum efficiency of 12.6% (57.8 cm²; AM1.5) could be demonstrated on an in-line roll-to-roll fabricated single device and a support structure prototype with a projected area density <1 kg/m² has been demonstrated. An earlier version of this constantly evolving technology was successfully tested on-orbit as part of the TET-1 mission

ILGAR In2S3 buffer layers for Cd free Cu In,Ga S,Se 2 solar cells with certified efficiencies above 16

In2S3 buffer layers have been prepared using the spray ion layer gas reaction deposition technique for chalcopyrite based thin film solar cells. These buffers deposited on commercially available Cu In,Ga S,Se 2 absorbers have resulted in solar cells with certified record efficiencies of 16.1 , clearly higher than the corresponding CdS buffered references. The deposition process has been optimized, and the resulting cells have been studied using current voltage and quantum efficiency analysis and compared with previous record cells, cells with a thermally evaporated In2S3 buffer layer and CdS references