Tianmin Wang

Photocatalytic properties of BiOX (X = Cl, Br, and I)

A novel series of photocatalysts, bismuth oxyhalide (BiOX, X = Cl, Br, and I), were synthesized by a hydrolysis method. The powder samples were characterized by the use of X-ray diffraction (XRD), scanning electron microscope, and UV-Vis spectrophotometer. The XRD pattern showed that all the BiOX were well crystallized in the tetragonal structure. The band gaps of the sheet-shaped compounds BiOX (X = Cl, Br, and I) were 3.44, 2.76, and 1.85 eV, respectively. BiOBr showed the highest photocatalytic activity in degrading rhodamine B (RhB) and evolving O2 for its proper valence band (VB). BiOI has no photocatalytic activity. BiOCl showed the highest activity in decomposing isopropanol because of electron-hole pair separation through trapping electrons by oxygen vacancies.

A new all-thin-film electrochromic device using LiBSO as the ion conducting layer

An all-thin-film electrochromic device glass/ITO/NiOx/LiBSO/WO3/ITO was fabricated by magnetron sputtering, in which LiBO2 + Li2SO4 (LiBSO) was used as the new ion conducting layer. The average visible light transmittances of bleached and coloured states reached 56.8% and 4.6%, respectively, and the optical transmittance modulation can reach 52.2%. The effect of substrate temperature on the device performance was investigated by comparing liquid nitrogen cooling and water cooling. The results showed that the device had a better electrochromic performance when fabricated at a low substrate temperature.

Rectifying Characteristics and Semiconductor–Metal Transition Induced by Interfacial Potential in the Mn3CuN/n-Si Intermetallic Heterojunction

The Mn3CuN/n-Si heterojunction device is first designed in the antiperovskite compound, and excellent rectifying characteristics are obtained. The rectification ratio (RR) reaches as large as 38.9 at 10 V, and the open-circuit voltage Voc of 1.13 V is observed under temperature of 410 K. The rectifying behaviors can be well described by the Shockley equation, indicating the existence of a Schottky diode. Simultaneously, a particular semiconductor-metal transition (SMT) behavior at 250 K is also observed in the Mn3CuN/n-Si heterojunction. The interfacial band bending induced inversion layer, which is clarified by the interfacial schematic band diagrams, is believed to be responsible for the SMT and rectifying effects. This study can develop a new class of materials for heterojunction, rectifying devices, and SMT behaviors.