Preparation of MgF2/SiO2 coating with broadband antireflective coating by using sol–gel combined with electron beam evaporation

Abstract

The broadband antireflective coatings (ARCs) can effectively reduce the optical loss in the transmittance process and improve energy efficiency in solar cells. MgF2/SiO2 bilayer films were prepared on the surface of soda–lime substrates via sol–gel spin-coating combined with electron beam (e-beam) evaporation. The bottom layer was the MgF2 film obtained from e-beam evaporation, whereas the top layer was the nanoporous SiO2 film via sol–gel spin-coating method. The refractive indices of MgF2 and SiO2 layers at 550 nm are 1.38 and 1.12, respectively. The structural, morphological, and optical properties of the films were characterized. The effects of annealing temperature, Triton X-100 concentration, and spin-coating speed on the properties of the film were investigated. The transmittance spectra of the coatings were investigated, and the broadband antireflective performance of the bilayer structure was examined. A bilayer coating with optical properties close to the theoretical design results was obtained by optimizing the refractive index and the thickness of the double coatings. The solar transmittances of the soda–lime glass coated with the MgF2/SiO2 bilayer antireflective film increased by 8.89% at 400–800 nm. The multilayer antireflective film exhibits promising applications in photoelectric devices, high power laser systems, and antidazzle glasses.