Jintao Tian

Characterization of nucleation and growth kinetics of the formation of water-soluble CdSe quantum dots by their optical properties

The nucleation and growth kinetics of the formation of water-soluble CdSe quantum dots (QDs) was characterized by measurements of their optical properties of ultraviolet?visible and fluorescence spectra. The QDs were synthesized using thioglycolic acid as a capping agent. Two kinetic parameters, reaction temperature and time, were varied over wide ranges 20?90??C and 0?12?h, respectively. Our results showed that a low reaction temperature was preferable for the nucleation process, resulting in relatively small particles and a narrow size distribution. The subsequent grain growth was mainly achieved within 1?h. The reaction temperature virtually affected the kinetic features of the QDs. The fluorescence measurements revealed largest variations of the fluorescence features for the 70??C samples. From a viewpoint of controls of fluorescence colour and intensity over a wide range, a reaction temperature of 70??C was appropriate for the CdSe QD synthesis.

One-pot synthesis in liquid paraffin of ternary alloy CdSexS1−x nanocrystals with fluorescence emission covering entire visible region

The ternary alloy CdSexS1−x nanocrystals are synthesized in liquid paraffin via one-pot method. The fluorescence emission of the nanocrystals can be altered from violet to green by adjusting the ratio of Se to S without particle size change. By applying subsequent surface modification of the nanocrystals with amine, the fluorescence emission from yellow to red is successfully obtained that is achieved from trap emission enhancement. As a result, the combination of these two approaches makes the fluorescence emission of the ternary alloy CdSexS1−x nanocrystals covering entire visible region from violet to red while their sizes are similar and keep constant.

Anticorrosion Behavior of Superhydrophobic Composite Coating on Carbon Steel in Seawater

The anticorrosion behavior of the superhydrophobic composite coating in sterilized seawater is investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning e...

Colorimetric and fluorometric dual-mode detection of aniline pollutants based on spiropyran derivatives

The selective UV-vis absorption of spiropyran (SP) and the fluorescence quenching of a SP-cellulose material induced by aniline were observed in this study, which were exploited for rapid detection and accurate quantitative determination of aniline pollutants in the environment. The concentration of aniline pollutants can be rapidly evaluated by the naked eye in a colorimetric and fluorometric dual-mode by the SP-cellulose test paper. Furthermore, the aniline pollutants can also be accurately determined using the above materials with the aid of portable spectrophotometers. The detection processes are effective, low cost and easy to operate, and do not require personnel with expertise or cumbersome equipment, and are therefore especially suitable for real-time-field monitoring of aniline pollutants outdoors.

Anisotropic Growth of Porous Anodic Alumina and Its Potential Application in Three-Dimensional Nanostructure Construction

The porous anodic alumina was fabricated by means of electrochemical oxidation using Al foil as a substrate in oxalic acid under constant anodic voltage at room temperature. Prior to anodization, the substrate surface with roughness in microscale was obtained through electrochemical treatment. The tube growth on the substrate was investigated using a scanning electron microscope (SEM). The results showed that the tube growth behavior of the porous anodic alumina was strongly dependent on the surface roughness. In presence of sphere-shaped cavities in microscale (diameter of 5~30 μm) on the surface of the substrate, the nanotubes were growing essentially away from the center of curvature of each cavity, forming individual growing regions separated by visible interface. The tube branching and tube cutoff were evidently observed in the growing regions and along the interface, respectively. Anisotropic growth of porous anodic alumina suggested its potential application in three-dimensional nanostructure construction.

Blended additive manipulated morphology and crystallinity transformation toward high performance perovskite solar cells

The efficiency of a perovskite solar cell is highly affected by the crystal quality and morphology of its perovskite layer. A facile strategy of using blended organic additives to regulate the films crystallinity and coverage is studied in this work. The coordination behavior and sublimation temperature of the additives are the essential characteristics which determine the quality of the perovskite films. By introducing a certain amount of MACl, a kind of crystallinity-preferred additive, to partially replace MAAc, a coverage-preferred additive, the films crystallinity has been obviously improved at no expense of coverage, which results in a lower trap density, higher efficiency and better stability.