SiOx(C)/SiNx dual-layer anti-reflectance film coating for improved cell efficiency

Abstract

Light-induced plating (LIP), in which the current driving the metal reduction process is derived from illuminated solar cells, is an attractive technique for solar cell metallization because of its potential simplicity. However, applying the LIP techniques on standard acidic-textured multicrystalline silicon wafers with a silicon nitride-coated surface presents a challenge. The use of a spray-on carbon-doped non-stoichiometric silicon oxide [SiOx(C)] dielectric film before nickel and silver plating can greatly reduce background plating while helping decrease the reflectance on the front of silicon solar cells. The sprayed dielectric films have low refractive indices of 1.3–1.4, depending on the annealing temperature. Simulation studies show that the SiOx(C)/SiNx dual-layer anti-reflective coating has a lower weighted reflectance against an AM 1.5 G spectrum compared with the SiNx single coating. Finally, the performance of the laser-doped solar cells with a standard SiNx as an anti-reflectance coating were compared with those with the SiOx(C)/SiNx double-layer stack. An efficiency of 16.74% on a large, commercial-grade, p-type, multicrystalline silicon substrate was achieved.