NOVELTY - Producing printable, highly viscous oxide medium, comprises carrying out anhydrous sol-gel-based synthesis by condensation of (a) two- to four-fold symmetrically and/or asymmetrically substituted alkoxysilanes and alkoxyalkylsilanes with (b) strong carboxylic acids, and producing pasty, highly viscous medium (pastes) by controlled gelation.    USE - The printable, highly viscous oxide medium is useful for (i) producing diffusion barriers in machining processes of silicon wafers for photovoltaic, microelectronic, micro-mechanical and micro-optical applications, (ii) producing passivated emitter and rear cell structure-, passivated emitter with rear locally diffused-, passivated emitter, rear totally diffused-, interdigitated back contact solar cells, (iii) producing thin, dense glass layers on the cover glass of a display made of doped silicon dioxide, which prevent the diffusion of ions from the cover glass in the liquid crystalline phase, (iv) producing a handle- and abrasion-resistant layer on silicon wafers, and (v) producing diffusion barriers on silicon wafers against phosphorus and boron diffusion, where (a) the oxide medium, which is printed on the surface of the silicon wafer, is dried at a temperature of 50-950 degrees C, preferably 50-400 degrees C with at least one sequential annealing step (annealing by means of a step function) and/or an annealing-platform, and compressed for glazing to obtain a grip- and abrasion-resistant layer with a thickness of up to 500 nm, and the solar cells comprises additional architectural features, preferably metal wrap through, emitter-wrap-through, selective emitter, selective front surface field, selective back surface field or bifaciality, and (c) the silicon wafers are printed with the high-viscosity oxide medium, and the printed layers are thermally densified (all claimed).    ADVANTAGE - The method uses a capping agent comprising acetoxytrialkylsilane, alkoxytrialkylsilane, halotrialkylsilane and its derivatives for improving the stability of the oxide medium (claimed). The oxide medium produces products with improved durability.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the oxide medium, which is produced by the above mentioned method, comprising binary or ternary system comprising silicon dioxide-alumina and/or mixtures of higher degree, where oxide medium is obtained using alcoholates/esters, acetates, hydroxides or oxides of aluminum, germanium, zinc, tin, titanium, zirconium or lead.