Abstract: Superstrates containing ETCs in accordance with various embodiments of the invention can be implemented to reduce optical losses by decreasing the thickness of the TCO and by reducing or eliminating shading losses of metal grid fingers. ETC superstrates can include a transparent material with grooves, which can be infilled with reflective, conductive material(s) such as but not limited to silver and aluminum. In further embodiments, the grooves are triangular-shaped. ETC superstrates can enable a significant reduction in the TCO thickness required for current extraction with a high fill factor. By reducing the thickness of the TCO layer in solar cells, the short circuit current density can be enhanced by more than 1 mA/cm2 due to decreased parasitic absorption and optimized antireflection properties.