Kuihong Yao

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 (~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.

Synthesis of ZnO rods by a simple chemical solution deposition method

ZnO short rods with large yield have been synthesized by a simple chemical solution deposition method at a low temperature of 80°C. Polymethyl methacrylate was used as the structure-directing agent in the formation of the rod-like ZnO crystals. X-ray powder diffraction and field emission scanning electron microscopy were used to characterize the obtained product. The results showed that the as-prepared ZnO crystals were rod-like, which have fairly uniform diameter of around 0.5 ∼ 2 μm and length of 4 ∼ 6 μm. A possible formation mechanism of the ZnO rods has been considered.