Ab initio study of electronic and structural properties of SnO2 nanoparticles under pressure

ABSTRACT Tin oxide (SnO2) has important applications, including as an elective material in the development of gas sensors. These devices improve their sensitivity and decrease their work temperature when the nanoparticle size is in the nanoscale order. Therefore, the gas sensor raises its efficiency noticeably. For this reason, the research of behavior at the nanoscale is essential. The total and surface formation energies of SnO2 nanoparticles (NPs) were determined by means of ab initio calculations at different concentrations and size near to 2.5 nm. The analysis shows that at higher concentration, higher structural stability is reached, in the range of 0 to 10 GPa (applied external pressures). In addition, it was possible to define a crystalline core region and a distorted layer in the NP by way of the atomic displacement study. Taking into account the importance of detecting the NP size by X-ray diffraction (XRD), the crystalline core dimension was estimated at 0 GPa. We obtained crystalline cores of 1.46 nm in the case of 1.9-, 2.0- and 2.2- concentrations, while this core was not observed at pressures of 5 and 10 GPa. Observing different regions in the densities of electronic states (DOS), we confirmed the core sizes in each NP.