Synthesis, Structure and Magnetic Properties of CoNi Submicrospherical Chains

High-purity magnetic CoNi submicrospherical chains, each of length 20 μm - 30 μm and self-assembled from fcc-phase CoNi submicrospheres of average diameter 800 nm, are synthesized via a surfactant-assisted solvothermal route without the aid of nucleation agent. The effects of surfactant and reducing agent on the morphology and size of the CoNi chains are studied, and a possible growth mechanism for the CoNi chains is proposed. The CoNi chains show ferromagnetic characteristics with a similarly small saturation magnetization of 104.1 emu/g and a larger coercivity of 150 Oe at room temperature compared to the monodispersed CoNi submicrospheres of 105 emu/g and 34 Oe as a result of the increased shape anisotropy.

Fast synthesis of monodisperse TiO_2 submicrospheres via a modified sol-gel approach

Monodisperse titania glycolate submicrospheres were synthesized by a modified sol-gel route, in which ultrasonic treatment was introduced to improve the reaction efficiency. The as-prepared products were characterized by means of Fourier transform infrared spectrum （FT-IR）, transmission electron microscopy （TEM）, powder X-ray diffraction （XRD）, and scanning electron microscopy （SEM）. The results indicate that the as-prepared products are titania glycolate submicrospheres with diameters of 230-330 nm. The average particle diameter is estimated to be about 280 nm. Ultrasonic treatment has an important influence on the morphology of the produced titania glycolates. After calcination at 450°C for 2 h, these titania glycolates were completely converted into anatase TiO2. The morphology of TiO2 particles was well reserved during the calcination process except for a reduction of 18% in the average particle size.

Template-free Fabrication and Luminescent Characterization of Highly Uniform and Monodisperse Y_2O_2S:Sm^(3+) Hollow Submicrospheres

Well dispersed and homogeneous Y2O2S：Sm3＋ hollow submicrospheres were successfully achieved by a template- free solvothermal method combining with a postcalcining process. The crystalstructure and particle morphology were investigated by the X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectra, scanning and transmission electron microscopy （SEM and TEM）, respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the Y202S：Sm3＋ long-lasting phosphor were an- alyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. The excitation spectra indicated that the phosphor could be excited effectively by the ultraviolet-light emitting diode （UV-LED） or blue LED, and the emission spectra showed that the phosphor could emit red light from 600 to 650 nm.

Surface states in TiO2 submicrosphere films and their effect on electron transport

Owing to their special three-dimensional network structure and high specific surface area,TiO2 submicrospheres have been widely used as electron conductors in photoanodes for solar cells.In recent years,utilization of TiO2 submicrospheres in solar cells has greatly boosted the photovoltaic performance.Inevitably,however,numerous surface states in the TiO2 network affect electron transport.In this work,the surface states in TiO2 submicrospheres were thoroughly investigated by charge extraction methods,and the results were confirmed by the cyclic voltammetry method.The results showed that ammonia can effectively reduce the number of surface states in TiO2 submicrospheres.Furthermore,in-depth characterizations indicate that ammonia shifts the conduction band toward a more positive potential and improves the interfacial charge transfer.Moreover,charge recombination is effectively prevented.Overall,the cell performance is essentially dependent on the effect of the surface states,which affects the electron transfer and recombination process.

Synergistic effect of TiO_2 hierarchical submicrospheres for high performance dye-sensitized solar cells

The performance of dye-sensitized solar cells(DSCs) could be improved by using rationally designed mesoporous film structure for electron collection, dye adsorption and light scattering. The development of a novel double layer film prepared by TiO_2 hierarchical submicrospheres and nanoparticles was reported in this article. The submicrospheres were composed of rutile nanorods of 10 nm diameter and the length of 150–250 nm, which facilitated fast electron transport, charge collection and light scattering. Using a double layer structure consisting of the 10 wt% film as a dye loading layer and the 50 wt% film as the light scattering layer, C101 sensitizer and liquid electrolyte, DSC yielded power conversion efficiency of 9.68% under 1 sun illumination.