Broadband antireflection enhancement of c-Si solar cells by less 1/10 wavelength and subwavelength of silica nanosphere coatings

Monodisperse silica nanospheres with different diameters between 100 and 700 nm were fabricated using a slightly modified Stöber process. Silica nanosphere monolayers in a hexagonal array based on hydrophobically modification were well deposited on top of a bare crystalline silicon solar cell by a Langmuir-Blodgett method. The antireflection effect of various diameter silica nanospheres coatings was simulated using Comsol Multiphysics simulations. Silica nanosphere hexagonal array coatings with four kinds of diameters were fabricated based on results of simulations. The efficiency of solar cells covered by silica nanospheres has improved significantly with a maximum of 11.41% at 119 nm diameter while that of the planar solar cells was 10.17%, which is attributed to the improved photocurrents arising from the broadband antireflection and optical absorption. The antireflection effects produced by Rayleigh (<1/10 wavelength) and Mie scattering (subwavelength) of different diameters silica nanosphere structures were discussed in detail.