Investigations on structural, optical and electrochemical properties of blue luminescence SnO2 nanoparticles

A simple solution approach has been developed to synthesis SnO2 nanoparticles using polyethylene glycol as stabilizer. X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), UV-Vis absorption spectroscopy, photoluminescence (PL) emission spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the nanoparticles. XRD, HR-TEM and AFM indicate that the SnO2 nanoparticles correspond to tetragonal crystal structure with size ranges below Bohr's exciton radius. UV-Vis absorption spectrum showed band gap exhibiting a 1.3 eV shift from that of bulk SnO2 structures. The blue emission owing to transition of an electron from conduction band to deeply trapped hole in SnO2 nanoparticles was analyzed using PL spectroscopy. The charge transfer capability had been investigated using CV and EIS in different electrolytes. A detailed exploration on confinement effect that occurred in SnO2 nanoparticles, mechanism behind visible emission and electron transfer mechanism in different electrolyte was discussed.