Rong Wu

Graphene oxide/core–shell structured TiO2@TiO2−x nanocomposites with highly efficient visible-light photocatalytic performance

Graphene oxide/core–shell structured TiO2@TiO2−x nanocomposites with outstanding photocatalytic performance were prepared by combining graphene oxide and black titania. Ti3+ and graphene oxide as a mediator of electron transfer were introduced into the compounds, which strongly enhanced visible-light absorption and photocatalysis.

The interface degradation of planar organic–inorganic perovskite solar cell traced by light beam induced current (LBIC)

The light beam induced current (LBIC) method was adopted to nondestructively map the photoresponse of real planar organic–inorganic hybrid perovskite solar cells (PSCs). It is found that the photoresponse of the devices is not uniform even though the morphology of the perovskite films from scanning electron microscope (SEM) or atomic force microscope (AFM) images shows uniform character. This nonuniformity of the photoresponse of the devices is further exacerbated after degradation, which can be well traced by the LBIC method. The indistinguishable morphology change during the device degradation indicates that the degradation of the device is not mainly determined by the morphology of the perovskite layer, but by the interface between the perovskite and the electrode. By using the LBIC method, the worse performing area of the device is identified and then removed accordingly. The current density of the device can be enhanced from 19.44 mA cm−2 to 21.72 mA cm−2 after this clearance of the worse performing area.

Solvothermal Synthesis of Single-Crystal Bismuth Selenide Nanoplates

Bismuth Selenide (Bi2Se3) nanoplates have been synthesized via a facile solvothermal route using the mixed solvents of ethylenediamine (EN) and ethylene glycol (EG) with the assistant of polyvinylpyrrolidone (PVP). The X-ray diffraction and Transmission electron microscopy (TEM) indicate that the nanoplates are well-crystallized single crystals with rhombohedral phase. Scanning electron microscopy (SEM) observations show that the nanoplates have approximate hexagonal outer shape with lateral length of 200–600 nm and thickness of 80–160 nm. The influences of solvents and PVP on the growth of the nanoplates were checked and it is found that EN can facilitate the formation of plate-like morphology while EG and PVP can benefit the uniform hexagonal outer shape. The P-type conduction of the Bi2Se3 nanoplates is revealed by Hall measurement.

C/Si/core–shell structured TiO2@TiO2−x nanocomposites with excellent visible-light photocatalytic performance

C/Si/core–shell structured TiO2@TiO2−x nanocomposites were obtained by combining C, Si and black TiO2. Amounts of Ti3+ and oxygen vacancies in TiO2@TiO2−x and the electron transfer among C, Si and TiO2@TiO2−x inhibited electron/hole recombination, which resulted in excellent photocatalytic performance.

Structure and optical properties of Sn doped delafossite oxides CuGaO2 by hydrothermal method

abstract CuGa1-×Sn×O2 (0 ≤ × ≤ 0.1427) samples were synthesized by convenient hydrothermal method. The crystal structure and optical properties were also investigated. Results revealed that the CuGa1-×Sn×O2 samples are delafossite oxides with a rhombohedral (space group R-3m) structure; the XPS spectra confirmed that the valence state of Sn is +4. Increasing the concentration of doped Sn atoms decreased the band gap from 3.83 eV to 3.45 eV. The offset of the X-ray diffraction pattern and the change in transmittance indicated that the critical threshold was reached when the Sn concentration reached 6.23 at.%.