Silicon solar cells: evolution, high-efficiency design and efficiency enhancements

Abstract

With a history dating back over 50 years, silicon solar cells were amongst the first bipolar silicon devices demonstrated. Notwithstanding this long history, the last ten years have seen rapid progress in both the efficiency of experimental devices and in the understanding of basic design constraints. The evolution of silicon cell design over the last 50 years is described and the features of current high-efficiency devices are discussed in some detail. With energy conversion efficiencies above 23%, these devices are now approaching basic limits for conventional homojunction cells. The potential for substantially increasing cell performance above these limits, by taking advantage of concepts such as the impurity photovoltaic effect, the incorporation of alloys and superlattices, and tandem cells based on silicon, is discussed.