Amorphous Ta_2O_5 films were prepared on Si (100) substrates by thermal oxidization.The film consisted of amorphous Ta_2O_5 nanostructure that grew vertically and compactly at a large range.It was found that Ta_2O_5 ...Amorphous Ta_2O_5 films were prepared on Si (100) substrates by thermal oxidization.The film consisted of amorphous Ta_2O_5 nanostructure that grew vertically and compactly at a large range.It was found that Ta_2O_5 films became crystalline when annealed at or above 650℃and remained amorphous below 650℃.The effects of annealing on the optical properties of Ta_2O_5 film were also discussed.It is estimated that the refraction indexes and the optical energy gaps of both amorphous Ta_2O_5 film and crystal one are stable.The optical energy gap of as-deposited Ta_2O_5 film is about 4.81 eV.The above results indicate that Ta_2O_5 films have a promising application in the optical devices.展开更多
Nano sized powders of TiO2 （titanium dioxide） and Nb2O5 （Niobium （V） oxide） were used to fabricate TiO2/Nb2O5 composites thin films by EPD （electrophoretic deposition） technique. The metal oxide powders, toget...Nano sized powders of TiO2 （titanium dioxide） and Nb2O5 （Niobium （V） oxide） were used to fabricate TiO2/Nb2O5 composites thin films by EPD （electrophoretic deposition） technique. The metal oxide powders, together with magnesium nitrate hexahydrate pellets, were suspended in propan-2-ol inside an EPD cell. The electrodes, placed 1.2 cm apart, were partially immersed in the suspension and a DC potential applied across them. Key EPD process parameters, which include applied DC electric field, deposition time and solid concentration in suspension, were optimized through visual inspection and from UV-Vis-NIR spectrophotometer spectra. The highest （55%） transmittance was obtained for films with deposition time of 90 s, powder concentration of 0.01 g/40 mL, and 35 V DC （direct current） voltage. XRD micrographs confirmed that TiO2 and Nb2O5 particles were presented in the composite film. SEM （scanning electron microscope） micrographs of the composite electrode thin films showed that porous films of high quality with well controlled morphology were deposited by using the EPD technique.展开更多
We have performed time-resolved degenerate four-wave mixing (DFWM) experiments in 75Nb2O5-20TeO2-5ZnO glasses doped by Er2O3 at different excitation intensities and lattice temperatures. DFWM signal exhibits three pea...We have performed time-resolved degenerate four-wave mixing (DFWM) experiments in 75Nb2O5-20TeO2-5ZnO glasses doped by Er2O3 at different excitation intensities and lattice temperatures. DFWM signal exhibits three peaks at high excitation intensities, where a main peak appears at zero time delay and two rather weak side peaks locate symmetrically at the negative and positive time delay, respectively. The main peak is attributed to local-field effect and two side peaks are attributed to Coulomb interaction (CI).展开更多
A series of silica-phosphate nano-composites prepared as a host thin films Physical Properties of Nano-Composite Silica-Phosphate Thin Film Prepared by Sol Gel Technique and doped with different concentrations of Er3+...A series of silica-phosphate nano-composites prepared as a host thin films Physical Properties of Nano-Composite Silica-Phosphate Thin Film Prepared by Sol Gel Technique and doped with different concentrations of Er3+ ions have been synthesized using tetraesoxysilane TEOS, triethylphosphate TEP and erbium nitrate as precursor sources of silica, phosphorus and erbium oxides. The structural properties of pure silica-phosphate thin films and doped with different concentrations of Er3+ ions were studied, using x-ray diffraction (XRD) and Fourier Transform Infrared (FTIR). The morphology of silica-phosphate was characterized by Scanning electron microscope (SEM).展开更多
The role of wide band gap oxide thin layer in inverted structure polymer solar cells was investigated by employing oxide films of TiO2 and Nb2O5approximately 10 nm in thickness deposited onto FTO substrates. The exper...The role of wide band gap oxide thin layer in inverted structure polymer solar cells was investigated by employing oxide films of TiO2 and Nb2O5approximately 10 nm in thickness deposited onto FTO substrates. The experimental results demonstrated that the thin oxide layer serving to separate the electron collecting electrode and the photoactive film of a blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) was necessary to promote the formation of continuous uniform PCBM film to block holes in P3HT from being recombined with electrons in collecting electrode. A use of TiO2 buffer layer leads to power conversion efficiency as high as 2.8%. As for Nb2O5, in spite the fact that its conduction band is higher than the LUMO level of PCBM polymer acting as electron transport material, a power conversion of 2.7%, which was only slightly different from the 2.8% achieved for the cell employing TiO2. These experimental results suggest a tunneling mechanism for the electrons to transport from the PCBM to collecting electrode over the oxide film, instead of a diffusion through the oxide film arising from either energy or concentration difference of the photogenerated electrons.展开更多
文摘Amorphous Ta_2O_5 films were prepared on Si (100) substrates by thermal oxidization.The film consisted of amorphous Ta_2O_5 nanostructure that grew vertically and compactly at a large range.It was found that Ta_2O_5 films became crystalline when annealed at or above 650℃and remained amorphous below 650℃.The effects of annealing on the optical properties of Ta_2O_5 film were also discussed.It is estimated that the refraction indexes and the optical energy gaps of both amorphous Ta_2O_5 film and crystal one are stable.The optical energy gap of as-deposited Ta_2O_5 film is about 4.81 eV.The above results indicate that Ta_2O_5 films have a promising application in the optical devices.
文摘Nano sized powders of TiO2 （titanium dioxide） and Nb2O5 （Niobium （V） oxide） were used to fabricate TiO2/Nb2O5 composites thin films by EPD （electrophoretic deposition） technique. The metal oxide powders, together with magnesium nitrate hexahydrate pellets, were suspended in propan-2-ol inside an EPD cell. The electrodes, placed 1.2 cm apart, were partially immersed in the suspension and a DC potential applied across them. Key EPD process parameters, which include applied DC electric field, deposition time and solid concentration in suspension, were optimized through visual inspection and from UV-Vis-NIR spectrophotometer spectra. The highest （55%） transmittance was obtained for films with deposition time of 90 s, powder concentration of 0.01 g/40 mL, and 35 V DC （direct current） voltage. XRD micrographs confirmed that TiO2 and Nb2O5 particles were presented in the composite film. SEM （scanning electron microscope） micrographs of the composite electrode thin films showed that porous films of high quality with well controlled morphology were deposited by using the EPD technique.
基金This work was suPPorted by Shanghai Priority Academic DisciPline,the National Natural Science Foundation of China(No.10234030 and 10074015),the National Key Project for Basic Research(No.1999075204),the Project Sponsored by Shangliai Science and Tech
文摘We have performed time-resolved degenerate four-wave mixing (DFWM) experiments in 75Nb2O5-20TeO2-5ZnO glasses doped by Er2O3 at different excitation intensities and lattice temperatures. DFWM signal exhibits three peaks at high excitation intensities, where a main peak appears at zero time delay and two rather weak side peaks locate symmetrically at the negative and positive time delay, respectively. The main peak is attributed to local-field effect and two side peaks are attributed to Coulomb interaction (CI).
文摘A series of silica-phosphate nano-composites prepared as a host thin films Physical Properties of Nano-Composite Silica-Phosphate Thin Film Prepared by Sol Gel Technique and doped with different concentrations of Er3+ ions have been synthesized using tetraesoxysilane TEOS, triethylphosphate TEP and erbium nitrate as precursor sources of silica, phosphorus and erbium oxides. The structural properties of pure silica-phosphate thin films and doped with different concentrations of Er3+ ions were studied, using x-ray diffraction (XRD) and Fourier Transform Infrared (FTIR). The morphology of silica-phosphate was characterized by Scanning electron microscope (SEM).
文摘The role of wide band gap oxide thin layer in inverted structure polymer solar cells was investigated by employing oxide films of TiO2 and Nb2O5approximately 10 nm in thickness deposited onto FTO substrates. The experimental results demonstrated that the thin oxide layer serving to separate the electron collecting electrode and the photoactive film of a blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) was necessary to promote the formation of continuous uniform PCBM film to block holes in P3HT from being recombined with electrons in collecting electrode. A use of TiO2 buffer layer leads to power conversion efficiency as high as 2.8%. As for Nb2O5, in spite the fact that its conduction band is higher than the LUMO level of PCBM polymer acting as electron transport material, a power conversion of 2.7%, which was only slightly different from the 2.8% achieved for the cell employing TiO2. These experimental results suggest a tunneling mechanism for the electrons to transport from the PCBM to collecting electrode over the oxide film, instead of a diffusion through the oxide film arising from either energy or concentration difference of the photogenerated electrons.
