A simple hydrothermal route for synthesizing SnO2 quantum dots

A simple hydrothermal process is proposed for synthesizing SnO2 quantum dots (QDs), in which hydrazine hydrate is used as the mineralizer instead of NaOH. X-ray diffraction, high-resolution transmission electron microscopy (HRTEM) and UV - vis diffuse reflectance spectroscopy (DRS) were employed to characterize the product. The HRTEM image shows that the diameters of the SnO2 nanoparticles fall into a small range of 2.3 - 3.1 nm, with the majority being less than the exciton Bohr radius of SnO2 (similar to 2.7 nm). Analysis of the DRS spectrum showed the band gap of the SnO2 QDs to be 3.88 eV, exhibiting a 0.28 eV blue shift from that of the bulk SnO2 (3.6 eV). The mechanism for hydrothermal synthesis of the SnO2 QDs using hydrazine hydrate as the mineralizer is discussed.