Optimal design of amorphous single-junction and tandem solar cells

✍ Scribed by John C.C. Fan; B.J. Palm

• Publisher: Elsevier Science
• Year: 1983
• Weight: 898 KB
• Volume: 10
• Category: Article
• ISSN: 0379-6787
• DOI: 10.1016/0379-6787(83)90009-1

✦ Synopsis

Computer analysis of amorphous solar cells indicates that a substantial increase in conversion efficiency can be achieved by using two,ell tandem structures instead of single-junction cells. A further increase in efficiency is calculated for three-cell tandem structures, but this increase is probably too small to justify their added complexity. Practical air mass 1 efficiencies of 16% -17% at 1 sun can be expected for optimal two-cell structures, compared with 12% -13% expected for single-junction cells. In optimal two-cell structures the top cell has a band gap of 1.85 eV, which is easily attainable with hydrogenated amorphous silicon films; the bottom cell has a band gap of 1.35 eV, which may be achieved with an alloy system such as hydrogenated amorphous Sil-xGex or hydrogenated amorphous Sil-xSnx. Either two-terminal or four-terminal configurations can be used for two¢ell tandem structures. The four-terminal configuration has the advantage of requiring less accurate control of film deposition parameters, since the efficiency depends less critically on the band gaps of the two component cells.