Effect of carbon containing SiNx antireflection coating on the screen-printed contact and low illumination performance of silicon solar cell

Abstract

Screen-printed metal contact formation through a carbon containing antireflection coating was investigated for silicon solar cells by fabricating conventional carbon-free SiNx and carbon-rich SiCxN y film. An appreciable difference was found in the average shunt resistance (Rsh), which was about an order of magnitude higher for SiCxNy-coated solar cells relative to the counterpart SiNx-coated solar cells. Series resistance (Rs) and fill factor (FF) were comparable for both antireflection coatings but the starting efficiency of SiCxNy-coated cell was ~0·2% lower because of slightly inferior surface passivation. However, SiCxN y-coated solar cells showed less degradation under lower illumination (<1000 W/m2) compared with the SiNx-coated cells due to reduced FF degradation under low illumination. Theoretical calculations in this paper support that this is a direct result of high Rsh. Detailed photovoltaic system and cost modeling is performed to quantify the enhanced energy production and the reduced levelized cost of electricity due to higher shunt resistance of the SiCxNy-coated cells. It is shown that Rsh value below 30 Ω (7000 Ω cm2 for 239 cm2 cell) can lead to appreciable loss in energy production in regions of low solar insolation. Copyright © 2011 John Wiley & Sons, Ltd.