This paper describes the successful development of a porous SiO2-containing antireflective coating ~110nm thick, which was applied by a sol-gel dip coating process and which increased light transmittance by up to 5%. Previous antireflective coatings did not have sufficient adhesion strength and resistance to wiping on borosilicate glass, so that they do not withstand the rough operating conditions seen in practice. The essential component enhancing the stability of the coating turned out to be H3PO4 which is added to the dropping solution. After baking the sol-gel layers for 1h at 500 deg C, both Na and P concentration peaks develop at both sides of the interface, obviously forming Na2O phosphosilicate glasses, assuring a high long term stability between glass and layer.
