Because of the increasing demand for photovoltaic energy and the generation of end-of-life photovoltaic waste forecast, the feasibility to produce glass substrates for photovoltaic application by recycling photovoltaic glass waste (PVWG) material was analyzed. PVWG was recovered from photovoltaic house roof panels for developing windows glass substrates; PVWG was used as the main material mixed with other industrial waste materials (wSG). The glass was casted by air quenching, annealed, and polished to obtain transparent substrates samples. Fluorine-doped tin oxide (FTO) was deposited as back contact on the glass substrates by spray pyrolysis. The chemical composition of the glass materials was evaluated by X-ray fluorescence (XRF), the thermal stability was measured by differential thermal analysis (DTA) and the transmittance was determined by UV-VIS spectroscopy. The surface of the glass substrates and the deposited FTO were observed by scanning electron microscopy (SEM), the amorphous or crystalline state of the specimens were determined by X-ray diffraction (XRD) and the sheet resistance was evaluated by the four-point probe method. The sheet resistance of the deposited FTO on the wSG substrate was 7.84 ± 3.11 Ω/□, lower than that deposited on commercial soda-lime glass (8.48 ± 3.67 Ω/□), meaning that this material could present improved conduction of the produced electrons by the photovoltaic effect. This process may represent an alternative to produce glass substrates from waste materials that could be destined for photovoltaic applications, especially the production of ecological photovoltaic windows.

To reduce environmental impacts from sodium silicate synthesis it was suggested the use of sugarcane bagasse ash (SCBA) as a source of silicon dioxide and sodium carbonate using the ceramic method. Although the production of sodium silicate is carried out on a large scale, it should be noted that its process requires temperatures above 1000 °C or the use of highly corrosive agents such as sodium hydroxide and chlorine gas used to neutralize the remaining sodium hydroxide. In the present work, the synthesis temperatures were reduced to 800 °C with a reaction time of 3 hours by pressing equimolar mixtures of previously purified SCBA and sodium carbonate, then heat treatment was carried out under the indicated conditions. The resulting materials were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Among the crystalline phases, calcium disodium silicate was identified, in addition to sodium silicate, so it was inferred that the other components of the ash can interfere with the synthesis of silicate. Therefore, to obtain the highest composition of sodium silicate, a leaching treatment of the SCBA is required.