Novel solar cell systems. Neue Solarzellen

摘要: Efficiency needs to be improved for a number of photovoltaic applications. There are two ways of doing this: (a) Cells with good efficiency can be modified i.e.by moving away from the conventional n{sup +}/p (or p{sup +}/n) and thinking up complicated, more efficient photovolta structures. This idea was pursued initially in two directions in the case of silicon: R. Swanson's point of contact cells and Green's PESC cells. Both were successful, and efficiency levels of over 23% were achieved under Am1.5. The highest value achieved under concentration (250 suns) was eta = 28.3. (b) The other way would be the development of an efficient (thin film) tandem cell. The optimum band gaps for 2-component tandem cells are 1.0 and 1.6 eV. High (tandem cell) efficiency levels can only be realised if both cell types are of a high standard individually. A project to study issue (a) has already been undertaken. It is the SIPOS cell, which offers an alternative to Swanson's point of contact cell and Green's PESC cell, both of which have the drawback of requiring several very expensive and complex process steps. The SIPOS cell, for which a maximum efficiency level of almost 30 % has been calculated, is somewhat simpler in structure and technology. The report concerns initial results and experience with the development of the SIPOS cell. (orig./ORU).