Texture properties of TCO uniquely determining light trapping in thin-film silicon solar cells

In superstrate thin-film solar cells a surface texture of the transparent conductive oxide (TCO) front contact is used to enhance short-circuit currents by both increasing the light input into the cell from refractive index grading and causing light trapping from optical scattering. The haze and root-mean-square roughness are inadequate to quantitatively account for increased light absorption and hence enhanced short-circuit currents. Rather, angle-resolved scattering combined with scattering-efficient components of the texture details were evaluated for different types of TCO materials to yield a fairly universal correlation between short-circuit currents and large-angle scattering, weighted by a texture-dependent scattering efficiency.