The light-trapping effect in various textured cover glass for enhancing the current density in silicon heterojunction solar cells

Light trapping by front surface texturing is considered an important mechanism since it can reduce the reflectance on the surface, enhance the photo-generated charge carriers and hence the performance of solar cells. Since the silicon (p, i, n) layers are deposited after surface texturing that may induce various defects leading to a reduction in open-circuit voltage (V_oc) and fill factor (FF). In this study, textured glass surfaces and silicon heterojunction solar cells (HJSCs) were prepared separately. The textured glass surface was optically coupled with the index matching solution (IMS) at the front surface of HJSCs for an enhancement in current density. Three wet chemical textured glass surfaces named Etch 1, Etch 2 and Etch 3 were employed based on various optical properties. It was observed during the current density–voltage (J–V) measurements that V_oc and FF of the device did not change. Reference HJSC coupled with flat glass showed J–V characteristic as V_oc=726.3 mV, FF=76.62%, J_sc=37.9 mA/cm², η=21.09% without IMS. The J_sc of HJSCs coupled with textured glass surface can be further enhanced by using IMS due to better light trapping. HJSCs coupled with textured glass (Etch 2) surface showed the highest J_sc of 38.4 mA/cm² with an efficiency of 21.4% without IMS whereas it showed an efficiency of 22.41% with J_sc of 40.2 mA/cm² using IMS. The trends in the external quantum efficiency of the HJSCs indicate that the J_sc can be improved if a suitable index matching solution and glass material are used.