Feasibility of Adding Antireflective Coating Foil Made from Nanoscale‐Patterned Optical Disk Templates on Industrial Silicon Photovoltaics

Abstract

Antireflective coating helps to reduce reflectance losses, thereby improving photovoltaic (PV) efficiency. Improving PV efficiency while maintaining low innovation cost has been a challenging task for the PV industry, especially in the case of monocrystalline silicon. Herein, the feasibility of integrating polydimethylsiloxane foil onto the protecting glass of an n‐type tunnel oxide–passivated contact silicon cell is studied. The foil is made using a polymer molding technique with digital video disk templates. On average, the foil provides 5.2% total reflectance and 93.5% total transmission. Under 1 sun illumination, the cell's power‐conversion efficiency increases by 12% (among the highest improvement), from 17.3% to 19.3%, in the presence of foil. A combined set of optical spectroscopy and simulation data shows that this improvement is due not only to the index‐matched medium, but also to forward scattering that increases broadband light transmission to the silicon cell through the foil which is different to the prevalent light‐trapping mechanism. The foil is also evaluated under different illumination conditions (indoors and outdoors), which show that the cell's power output nearly doubles at dimmer illumination levels and is stable under a fluctuating light source. While effective, the feasibility of antireflective foil should be reexamined further.