Angle-resolved characteristics of silicon photovoltaics with passivated conical-frustum nanostructures

Passivation plays a critical role in silicon photovoltaics, yet how a passivation layer affects the optical characteristics of nano-patterned surfaces has rarely been discussed. In this paper, we demonstrate conical-frustum nanostructures fabricated on silicon solar cells using polystyrene colloidal lithography with various silicon–nitride (SiNx) passivation thicknesses. The omnidirectional and broadband antireflective characteristics were determined by utilizing angle-resolved reflectance spectroscopy. The conical-frustum arrays with a height of 550 nm and a SiNx thickness of 80 nm effectively suppressed the Fresnel reflection in the wavelength range from 400 to 1000 nm, up to an incidence angle of 60°. As a result, the power conversion efficiency achieved was 13.39%, which showed a 9.13% enhancement compared to that of a conventional KOH-textured silicon cell. The external quantum efficiency measurements confirmed that the photocurrent was mostly contributed by the increased optical absorption in the near-infrared. The angular cell efficiencies were estimated and showed improvements over large angles of incidence.

Conical-frustum silicon nanorod arrays passivated with 80 nm-thick silicon nitride enhance cell efficiency up to an angle of incidence of 60° via omnidirectional antireflection.Figure optionsDownload as PowerPoint slideHighlights
► Si solar cells with passivated nano-conical-frustums outperform the conventional.
► Fabrication enabled by scalable polystyrene colloidal lithography.
► Angle-resolved reflectance confirms omnidirectional and broadband antireflection.
► Enhanced quantum efficiency due to increased optical absorption in the near-infrared.
► Improved power conversion efficiency over large angles of incidence.