The Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW), aiming to fast-track tandem solar technology's time to market, has put two new high-performance coating plants into operation.
The systems produce tandem solar cells consisting of a perovskite solar cell that can be combined with other types of solar cells. The various layers are deposited under ultra-clean conditions. Companies in the solar sector can take advantage of these capabilities to optimize their developments in the area of tandem solar cells.
A particularly interesting variant of tandem solar cells uses layers of perovskite as the light-absorbing material. For the second absorbing layer, ZSW researchers have opted to use cells made of copper, indium, gallium and selenium (CIGS), silicon, or another perovskite with a modified spectral sensitivity range. Combinations of different cell types ' that is, perovskite and CIGS, perovskite and silicon, or perovskite and perovskite ' hold great promise as a means of significantly boosting efficiency.
Tandem solar cells that pair perovskite with perovskite or perovskite with CIGS have benefits beyond high efficiency. As a thin-film technology, they can also be deposited on plastic or steel films to make light, flexible modules that are perfect for mounting overhead orchards, in vehicle roofs and integrated into building façades or roofs.
The ZSW now has two plants up and running to drive this development towards market maturity. One makes perovskite thin-film solar cells and the other CIGS thin-film solar cells. Tandem solar cells with silicon semiconductors can be produced on various silicon cells sourced from external partners.
'Excellent conditions are now in place in the institute to develop tandem solar cells, particularly in terms of the process technology for manufacturing solar cells in a vacuum under ultra-clean lab conditions. We want to use these assets to explore the technology's physical boundaries,' says Dr. Jan-Philipp Becker, the new head of the ZSW's Photovoltaics: Materials Research department. An extensive set of material analysis tools helps with that. The in-house Solab test laboratory and field-testing facilities are able to rigorously analyze and assess the manufactured solar cells and modules for long-term stability. The new plants will serve to develop innovative processes for the solar industry, which will then be able to bring to market more efficient and cost-effective solar modules.
Arrayed around a central robot, the perovskite cluster's four coating chambers can produce a wide variety of solar cells with sputtered trans-parent layers and with evaporated metallic or organic layers. A vacuum chamber provides optimized means of vacuum-coating perovskites. The system will be able to create very homogenous and highly reproducible multi-component perovskite layers. Even at this early stage, the ZSW has already made great strides in optimizing the cell structure with vapor-deposited organic electron conductor layers.
The German Federal Ministry of Economic Affairs and Climate Action (BMWK) funded the two plants as part of the CAPITANO and CIGS- Cluster projects.
