Improved Homogeneous Emitter Solar Cells with Double Layer Anti-Reflection Coatings

A double layer SiNx stack shows a better performance compared to conventional single layer SiNx ARC on monocrystalline silicon cells. The double layer SiNx ARC shows a lower reflectivity in the wavelength range of 350-500 nm than single layer SiNx, which is quite beneficial to the high sheet resistance emitters featuring good blue spectrum response. In this experiment, the solar cells have a traditional structure with optimized homogenous emitters (HE) having a sheet resistance of 75 Ω/sq. Well controlled screen-printing and firing conditions have led to a fill factor up to 79.0% and efficiency up to 18.9% on monocrystalline solar cells, and demonstrated a 0.5% efficiency gain compared to baseline solar cells with single layer SiNx ARC. In comparison to the single layer ARC, there is an increase of 2.8 mV in Voc and 0.4 mA/cm2 in Jsc. Furthermore, the fill factor is improved due to the fact that the screen-printed fingers show a better profile on the double layer ARCs’ cells.