Thinning out materials for solar modules
The 'Large-area CIS based thin-film solar modules for highly productive manufacturing' (Larcis) project set out to develop efficient manufacturing technologies for copper, indium and selenium (CIS) thin-film solar modules. The project aimed to achieve lower costs and stable, efficient and environmentally harmless CIS thin-film solar modules on large areas. Team members envisioned that support for such energy-saving technology would drive advances in applications for the photovoltaic (PV) market. Activities included work on the molybdenum (Mo) back contact, the buffer layer, the CIS absorber and on quality and process control. Project partners were able to show the high potential of evaporated indium(III) sulphide (In2S3) buffer layers in an industrial process and demonstrated their ability to form high-efficiency devices and high quality junctions. However, further work is needed to overcome certain difficulties related to industrial implementation. Development of the copper indium disulfide (CuInS2) technology promises to drive improvements in the performance of CIS cells on a large scale, while gallium (Ga) insertion activities can be enhanced through modification of related procedures. Knowledge generated regarding bath stability, influence of Mo resistivity and mass transfer phenomena offered an opportunity to create a pre-pilot line production employing a co-deposition and stack approach, as well as a process for CuInS2 cells. Larcis' efforts led to the development of cadmium (Cd)-free technology that, on the basis of experimental results, is capable of improving the efficiency of a copper indium gallium diselenide (CIGS) solar module. The application of a Cd-free layer on the electrodeposited CIGS was shown to improve the module's efficiency. Work performed on electrodeposition was also successful in lowering material and equipment costs for absorbing layer deposition thanks to a thinner CIGS layer, albeit with no improvements on CIGS efficiency.
