Bottom-up grown ZnO nanorods for an antireflective moth-eye structure on CuInGaSe2 solar cells

A bottom-up technique using an aqueous solution method was adopted to fabricate a bio-mimicked antireflection (AR) coating for a CuInGaSe2 (CIGS) solar cell. On controlling the morphology of the solution-grown zinc oxide (ZnO) nanostructure the average reflectance of the CIGS solar cell employing the bio-mimicked AR coating decreased from 6.14% to 1.46%, and the efficiency of the solar cell increased from 10% to 11.5%. The mechanism by which the solar cell′s efficiency was enhanced is thought to be the effect of the gradual increase in the refractive index between air and the top electrode due to the insertion of the ZnO nanostructure.

Graphical abstractSuitable antireflection coatings for CIGS solar cells having rough top surface were investigated by bottom-up grown moth-eye antireflective structure with zinc oxide (ZnO) nanorods (NRs).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Bottom-up moth-eye structure grown with self-organized ZnO nanorods (NRs) was introduced. ► ZnO NRs were optimized by theoretical calculation to get a better AR effect for a large area CIGS solar cell with a rough surface. ► Conical ZnO NR AR-coated case showed the best antireflection property. ► In CIGS solar cell adopted with the conical ZnO NR AR coating, conversion efficiency was remarkably improved.