Make manufacturing process for an important precursor of multiple solar cells marketable
Multilayer solar cells made of special crystalline compound semiconductors, so-called III / V semiconductors, are today the most efficient form of converting sunlight into electricity. Current processes achieve efficiencies of up to 46 percent. This high yield is possible because they consist of several superimposed layers. Multi-solar cells are used, for example, for the energy supply of satellites or in concentrating photovoltaics, which is dependent on high direct sunlight.
The individual III / V semiconductor layers are produced by means of organometallic chemical vapor deposition (MOVPE). Up to now, the highly toxic arsenic hydrogen has been used. With this so-called Group V precursor, however, only small deposition yields are obtained with respect to the arsenic used. By far the largest share is waste, which is not tolerable and expensive from the point of view of environmental protection and material efficiency. At this point, the research project TBAfuerPV is set up. The research group of three companies and one university aims to bring a new manufacturing process for the alternative Group V precursor Tertiary Butylarsin (TBA) to market. The production and qualification process for the significantly safer Group V precursor TBA is still too expensive and expensive so that TBA has not yet been used commercially for the production of multiple solar cells. In addition to the significantly improved and cost-effective production process for TBA, the project partners are also planning to develop a process for tertiary butylphosphine (TBP) in photovoltaic quality, another group V precursor.
The necessary purity and quality of the precursors is to be ensured by extensive chemical analysis, testing and control of photovoltaic cells. In addition, a concept for the environmentally sound recovery of the arsenic from MOVPE process waste is to be developed.