Efficiency enhancement of silicon solar cells with vertically aligned ZnO nanorod arrays as an antireflective layer

Vertically aligned ZnO nanorods grown by the hydrothermal method have been explored as an antireflection layer on polished, textured, and antireflection coating (ARC) coated textured silicon (Si) wafers. Average reflectance (from 380 to 1100 nm) of polished and textured Si wafers reduced from 32 to 9% and 14 to 2%, respectively. With nanorods, multiple light interactions and good optical impedance matching with graded refractive index (effective medium) from air to Si favored for light confinement in Si. Optimized nanorods on ARC coated textured Si cell led to an enhancement of photocurrent from 34.30 to 36.38 mA/cm2 and efficiency from 15.11 to 16.43%.