An approach toward 20-percent-efficient silicon solar cells

This paper shows that oxide surface passivation coupled with optimum multilayer antireflective coating can provide ∼3 percent (absolute) improvement in solar cell efficiency. Use of single-layer AR coating, without passivation, gives cell efficiencies in the range of 15- 15.5 percent on high-quality 4-Ω . cm as well as 0.1-0.2-Ω . cm float-zone silicon. Oxide surface passivation alone raises the cell efficiency to ≥ 17 percent. An optimum double-layer AR coating on oxide-passivated cells provides an additional ∼5-10 percent improvement over a single-layer AR-coated cell, resulting in cell efficiencies in excess of 18 percent. Experimentally observed improvements are supported by model calculations, and an approach to ≥20 percent efficient cells is discussed.