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 350-500nm 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 Omega/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 V-oc and 0.4 mA/cm(2) in J(sc). 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. (C) 2012 Published by Elsevier Ltd. Selection and peer-review under responsibility of the scientific committee of the SiliconPV 2012 conference.