Light-induced acoustic effect in LiNbO3：Fe：Ce crystals

The phenomena of acoustic emission in LiNbO3：Fe：Ce crystals have been observed in the process of light-induced quasi-breakdown. It is found that the ultra-high frequency acoustic signal introduced into the crystal is modulated by the low frequency acoustic waves. Its frequency increases with the increase of the intensity of incident light and its jump period of breakdown is the same as that of the photovoltaic current Ic, the change of light-induced refractive index △n and the diffracted light intensity L. This phenomenon has been analysed in this paper, which is caused by the inverse piezoelectric strain effect of the jump of space charge field during the quasi-breakdown.

Photocatalytic Degradation of NOx Under Visible Light Irradiation Using Fe-Doped Titanium Dioxide

In order to utilize visible light in photocatalytic conversion of NOx, Fe atoms were doped in commercially available photocatalytic TiO2 powders by impregnating method. The crystal phase of TiO2 was not changed after calcination process. Analysis by both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicated that Fe atoms were incorporated in TiO2 as Ti-O-Fe linkages. One significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. The Fe-doped TiO2 powder exhibited photocatalytic activity for the degradation of NOx under visible light irradiation. The sample mixed with 0.2 at% Fe3+and calcined at 600 ℃ showed the best photocatalytic activity.

Recent progress on mixed-anion type visible-light induced photocatalysts

Environmentally friendly soft chemical processes, including solvothermal/hydrothermal process and mechanochemical process,for the synthesis of mixed anion type visible-lightinduced photocatalysts are introduced in this review paper. Titania and strontium titanate based anion doped photocatalysts can be effectively prepared at such low-temperature as below 200 ℃. Especially,the mechanochemical process is a useful method for the synthesis of various mixed ions doping functional materials at low temperatures. The mixed anion type photocatalytic compounds consisted of N/O, N/F/O, S/O, N/C/O, show excellent visible light absorption ability and photocatalytic activities, indicating the potential applications in environmental purifications. Full-spectra active long wavelength light induced photocatalyst, full-time active photocatalyst system and infrared radiation(IR) shielding multifunctional photocatalysts will be introduced also.

Single-turnover and multiple-turnover measurement of phytoplankton photosynthesis parameters using variable light pulse induced fluorescence

Using a measurement system based on fluorescence induced by variable pulse light, photosynthesis parameters of chlorella pyrenoidosa are obtained, employing single-turnover and multiple-turnover protocols under darkadapted and light-adapted conditions. Under the light-adapted condition,σ’PSII is larger, and F’v/F’m（ST） and F’v/F’m（MT） are smaller than those of the dark-adapted condition, but the corresponding parameters possess good linear correlations.Fm（MT）, F’m（MT）, Fv/Fm（MT） and F’v/F’m（MT） which are measured using the multipleturnover protocol, are larger than those of the single-turnover protocol. The linear correlation coefficient between Fm（ST） and Fm（MT） is 0.984,and Fv/Fm（MT） = 1.18 Fv/Fm（ST） The linear correlation coefficient between F’m（ST） and F’m（MT） is 0.995, and F’v/F’m（MT） = 1.36 F’v/F’m/（ST）.

Black phosphorus induced photo-doping for high-performance organic-silicon heterojunction photovoltaics

In conventional crystalline silicon （Si） homojunction solar cells,a strategy of doping by transporting phosphorus or boron impurities into Si is commonly used to build Ohmic contacts at rear electrodes.However,this technique involves an energy intensive,high temperature （～ 800 ℃） process and toxic doping materials.Black phosphorus （BP） is a two-dimensional,narrow bandgap semiconductor with high carrier mobility that exhibits broad light harvesting properties.Here,we place BP：zinc oxide （ZnO） composite films between Si and aluminum （Al） to improve their contact.Once the BP harvests photons with energies below 1.1 eV from the crystalline Si,the ZnO carrier concentration increases dramatically due to charge injection.This photo-induced doping results in a high carrier concentration in the ZnO film,mimicking the modulated doping technique used in semiconductor heterojunctions.We show that photo-induced carriers dramatically increase the conductivities of the BP-modified ZnO films,thus reducing the contact resistance between Si and Al.A photovoltaic power conversion efficiency of 15.2% is achieved in organic-Si heterojunction solar cells that use a ZnO：BP layer.These findings demonstrate an effective way of improving Si/metal contact via a simple,low temperature process.