Linfeng Xu

Enhancement of photovoltaic performance of TiO2-based dye-sensitized solar cells by doping Ca3La3(1−x)Eu3x(BO3)5

A series of Ca3La3(1−x)Eu3x(BO3)5 (CLBO:3xEu3+) phosphors were prepared by the Pechini-type sol–gel technique. Rietveld refinement was performed using the powder X-ray diffraction data, which shows the occupation of Eu3+ on both Ca2+ and La3+ sites with a preferred location on the La3+ site over the Ca2+ site. In order to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs), a novel design is demonstrated by introducing CLBO:3xEu3+ in TiO2-based DSSC. As a new conversion luminescence medium, CLBO:3xEu3+ transfers ultraviolet light to visible light via down-conversion, and increases the solar light harvest and photocurrent of DSSC. The experimental results reveal the feasibility of the conversion luminescence by doping rare-earth phosphors in the DSSC, providing an effective novel method to improve the sunlight conversion efficiency for solar cells.

Template-free sonochemical synthesis of hierarchically porous NiO microsphere

A novel template-free sonochemical synthesis technique was used to prepare NiO microspheres combined with calcination of NiO2.45C0.74N0.25H2.90 precursor at 500 °C. The NiO microspheres samples were systematically investigated by the thermograviometric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier-transformed infrared spectroscopy (FT-IR), Brunnauer-Emmett-Teller (BET) nitrogen adsorption-desorption isotherms, laser particle size analyzer, and ultraviolet-visible spectroscopy (UV-Vis). The morphology of the precursor was retained even after the calcination process, and exhibited hierarchically porous sphericity. The morphology changed over the ultrasonic radiation time, and the shortest reaction time was 70 min, which was much less than 4h for the mechanical stirring process. The mechanical stirring was difficult to form the complete hierarchically porous microsphere structure. The BET specific surface area and the median diameter of the hierarchically porous NiO microspheres were 103.20 m(2)/g and 3.436 μm, respectively. The synthesized NiO microspheres were mesoporous materials with a high fraction of macropores. The pores were resulted from the intergranular accumulation. The ultraviolet absorption spectrum showed a broad emission at the center of 475 nm, and the band gap energy was estimated to be 3.63 eV.