Adsorption of single gold(Au)atom at three kinds of sites(hollow,bridge and top)on the hydroxylatedβ-cristobalite SiO2(111)surface was studied using the first-principles calculations with general gradient approximati...Adsorption of single gold(Au)atom at three kinds of sites(hollow,bridge and top)on the hydroxylatedβ-cristobalite SiO2(111)surface was studied using the first-principles calculations with general gradient approximation(GGA).The results of adsorption energies and density of electronic states(DOS)suggest that the hollow and bridge sites have the basically equal capability of binding Au,while the ability of the Top site is weaker.Two new energy levels emerge after the adsorption at all sites;in DOS of the Hollow configuration,one locates at-0.15 eV,composed of Au 5d and O 2p electronic states,another just crosses through the Fermi level,consisting of Au 6s,H 1s and O 2p.In addition,Mulliken population analyses indicate that electron transfer takes place between the Au atom and the surface H and O atoms in the Hollow and Bridge configurations,which can be used to interpret the adsorption of Au onto the positions.However,neither H nor O chemically bonds with Au atom.展开更多
The samples of Au/(Si/SiO2 )/p-Si structure were fabricated by using the R. F magnetron sputtering technique. Its carrier transport and electroluminescence mechanism were studied from the Ⅰ-Ⅴ curves and EL spectra...The samples of Au/(Si/SiO2 )/p-Si structure were fabricated by using the R. F magnetron sputtering technique. Its carrier transport and electroluminescence mechanism were studied from the Ⅰ-Ⅴ curves and EL spectra by using the Configuration Coordinate as a theoretical model. The result indicates that there are two defect centers in SiO2 films. The electron in Au and the hole in p-Si went into SiO2 film by the Fowler-Nordheim tunneling model at a high bias voltage and recombined through these defect centers in SiO2 film.展开更多
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma s...Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.展开更多
Highly homogeneous, well dispersed SiO_2@Au@TiO_2(SAT) microspheres decorated with Au nanoparticles(AuNPs) were prepared and incorporated into the photoanode with an optimized concentration gradientascent. The effects...Highly homogeneous, well dispersed SiO_2@Au@TiO_2(SAT) microspheres decorated with Au nanoparticles(AuNPs) were prepared and incorporated into the photoanode with an optimized concentration gradientascent. The effects of SAT microspheres and the gradient-ascent architecture on the light absorption and the photoelectric conversion efficiency(PCE) of the dye-sensitized solar cells(DSSCs) were investigated.Studies indicate that the introduction of SAT microspheres and the gradient-ascent architecture in the photoanode significantly enhance the light scattering and harvesting capability of the photoanode. The DSSC with the optimized SAT gradient-ascent photoanode has the maximum short circuit current density(Jsc) of 17.7 mA cm-2 and PCE of 7.75%, remarkably higher than those of the conventional DSSC by 23.7%and 28.0%, respectively. This significantly enhancement of the performance of the DSSC can be attributed to the excellent light reflection/scattering of SAT, the localized surface plasma resonance(LSPR) effect of AuNPs within the microspheres, and the gradient-ascent architecture of SAT microspheres inside the photoanode. This study demonstrates that the tri-synergies of the scattering of SAT microspheres, the LSPR of AuNPs and the gradient-ascent architecture can effectively improve the PCE of DSSC.展开更多
基金Funded by the Fundamental Research Funds for the Central Universities(No.CUGL100240)
摘要Adsorption of single gold(Au)atom at three kinds of sites(hollow,bridge and top)on the hydroxylatedβ-cristobalite SiO2(111)surface was studied using the first-principles calculations with general gradient approximation(GGA).The results of adsorption energies and density of electronic states(DOS)suggest that the hollow and bridge sites have the basically equal capability of binding Au,while the ability of the Top site is weaker.Two new energy levels emerge after the adsorption at all sites;in DOS of the Hollow configuration,one locates at-0.15 eV,composed of Au 5d and O 2p electronic states,another just crosses through the Fermi level,consisting of Au 6s,H 1s and O 2p.In addition,Mulliken population analyses indicate that electron transfer takes place between the Au atom and the surface H and O atoms in the Hollow and Bridge configurations,which can be used to interpret the adsorption of Au onto the positions.However,neither H nor O chemically bonds with Au atom.
摘要The samples of Au/(Si/SiO2 )/p-Si structure were fabricated by using the R. F magnetron sputtering technique. Its carrier transport and electroluminescence mechanism were studied from the Ⅰ-Ⅴ curves and EL spectra by using the Configuration Coordinate as a theoretical model. The result indicates that there are two defect centers in SiO2 films. The electron in Au and the hole in p-Si went into SiO2 film by the Fowler-Nordheim tunneling model at a high bias voltage and recombined through these defect centers in SiO2 film.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50842028 and 50972012)the National Basic Research Program of China (Grant No 2007CB613301)
摘要Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.
基金supported financially by the National Natural Science Foundation of China (Nos.51572102,11504101,11604089 and 11364018)
摘要Highly homogeneous, well dispersed SiO_2@Au@TiO_2(SAT) microspheres decorated with Au nanoparticles(AuNPs) were prepared and incorporated into the photoanode with an optimized concentration gradientascent. The effects of SAT microspheres and the gradient-ascent architecture on the light absorption and the photoelectric conversion efficiency(PCE) of the dye-sensitized solar cells(DSSCs) were investigated.Studies indicate that the introduction of SAT microspheres and the gradient-ascent architecture in the photoanode significantly enhance the light scattering and harvesting capability of the photoanode. The DSSC with the optimized SAT gradient-ascent photoanode has the maximum short circuit current density(Jsc) of 17.7 mA cm-2 and PCE of 7.75%, remarkably higher than those of the conventional DSSC by 23.7%and 28.0%, respectively. This significantly enhancement of the performance of the DSSC can be attributed to the excellent light reflection/scattering of SAT, the localized surface plasma resonance(LSPR) effect of AuNPs within the microspheres, and the gradient-ascent architecture of SAT microspheres inside the photoanode. This study demonstrates that the tri-synergies of the scattering of SAT microspheres, the LSPR of AuNPs and the gradient-ascent architecture can effectively improve the PCE of DSSC.