High-efficiency silicon heterojunction solar cells: From physics to production lines

Silicon heterojunction technology (Si-HJT) consists of thin amorphous silicon layers on monocrystalline silicon wafers and allows for photovoltaic solar cells with energy-conversion efficiencies above 20 %, also at industrial-production level. This article reports how this may be achieved. First, we focus on the surface-passivation mechanism of intrinsic and doped amorphous silicon films in such solar cells, enabling record-high values for the open-circuit voltage. Next, the industrial upscaling in large-area reactors of such film deposition is discussed, including the fabrication of solar cells with energy-conversion efficiencies as high as 21%.