A new type of silicon concentrator solar cell has been developed. It is called the point-contact cell because the metal semiconductor contacts are restricted to an array of small points on the back of the cell. The point contact cell has recently demonstrated 22 percent conversion efficiency at one sun and 27.5 percent at 100 suns.
Richard M. Swanson,
"Point Contact Silicon Solar Cells", Proc. SPIE 0706, Photovoltaics for Commercial Solar Power Applications, (20 November 1986); doi: 10.1117/12.937229; https://doi.org/10.1117/12.937229