New fluorine-containing alkoxysilane with branched cyclic substituent for preparing protective coatings with low refractive index

The search for new protective antireflection coat� ings for silicon solar cells, luminescent solar concen� trators, optical lenses, optical integrated circuit ele� ments, and laser crystals are currently in progress. The materials of such a kind should have a relatively low refractive index (less than 1.4), be capable of self� cleaning, which is characterized by the low surface energy of coatings. These properties allow antireflec� tion coatings to enhance the energy efficiency of opti� cal devices. They should also be sufficiently strong to function as protective coatings. Alkoxysilanes that are used at present as components for making these coatings contain organofluorine sub� stituents with a large relative content of fluorine atoms: R F = -CH 2 CH 2 (CF 2 ) n -CF 3 , where n = 1-8, or -CF(CF3)O(-CF2CF(CF3)O)n-C3F7, where n = 0-50 (1-4). At the same time, it is known from the lit� erature that the coatings of organic polymers obtained on the basis of monomers with branched or cyclic sub� stituents provide a possibility to reach the lowest values