Synthesis and characterization of the doped/co-doped SnO2 nanoparticles by the sol–gel method

Tin oxide (SnO₂) is one of the important semiconductors used in the application of solar cells because of its chemical–mechanical stability and wide band gap. These properties are very important for the performance development and photoanode optimization of a dye-sensitized solar cell (DSSC). However, the low conduction band value of SnO₂ reduces the photovoltaic efficiency, which limits the application of DSSC. Therefore, the doping strategy was used to increase the sensitivity to the visible light spectrum and change the light absorption properties of SnO₂. In this paper, pure SnO₂, Ag/SnO₂, Pt/SnO_2, and Pt/Ag/SnO₂ nanoparticles were synthesized at the nanoscale by a simple chemical sol–gel method. To characterize the structure, morphological/chemical properties, optical properties, and surface properties of the synthesized SnO₂ nanoparticles, X-Ray Diffraction (XRD), ultraviolet–visible, Brunauer–Emmett–Teller, Scanning Electron Microscopy (SEM)/Energy Dispersive X-Ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), and particle size analysis were respectively used. XRD results showed that the crystal sizes varied between 8.8 and 12.2 nm depending on the doping. Doping processes resulted in reductions in particle sizes. Optical studies resulted in decreases in the band gap with the doping process. The conclusions obtained have shown that Ag doping, and Pt–Ag co-doping can be promising for use as photoanode materials in semiconductor technology and especially in DSSC applications.