Preparation of ZnO Nanospheres and Their Applications in Dye-Sensitized Solar Cells

ZnO nanospheres are synthesized by a two-step self-assembly method. X-ray diffraction pattern and Raman scattering spectra measurements show that all the samples present a typical wurtzite structure. A regular sphere shape is inspected by field emission scanning electron microscope and transmission electron microscope for the samples. It is shown that the as-synthesized ZnO nanosphere is composed of numbers of primary particles with size of around 1Ohm. A possible growth mechanism for the two-step self-assembly ZnO nanosphere is proposed. After applying the ZnO nanospheres to dye-sensitized solar cells （DSSCs）, a 117% increase of the overall light to electricity conversion efficiency η is observed compared with that of the ZnO nanopartieles based DSSCs. Associated with the UV-vis results, light scattering is assigned to the great improvement of η.     

CuO Nanosheets Synthesized by Hydrothermal Process

CuO nanosheets are synthesized by oxidation of commercial Cu substrates through the hydrothermal process at 150℃. The as-synthesized nanosheets are characterized by powder x-ray diffraction, transmission electron microscopy, selected area electron diffraction and x-ray photoelectron spectroscopy. For comparison, Cu substrates are also oxidized without NaOH added in precursor solution. The results show that the morphology of CuO could be controlled by NaOH, which demonstrates that NaOH can serve as a cosolvent and modifier in the reaction system. The possible mechanism of the growth of CuO nanosheets is also discussed.     

Cu3N薄膜的制备及其霍尔效应研究

采用反应射频磁控溅射的方法在纯氮气气氛下、氮气流量为12sccm、衬底温度为100℃的条件下,在玻璃基底上成功制备了氮化铜(Cu3N)薄膜.XRD显示薄膜择优[100]晶向生长.用扫描电子显微镜(SEM)和原子力显微镜(AFM)观察了样品的表面形貌,发现样品表面平整、结构紧密.用四探针法检测了薄膜的霍尔特性,发现随温度的降低薄膜的霍尔系数、霍尔电阻率均增加.霍尔迁移率在高温范围也呈降低的趋势,但是变化的范围比较小,在低温范围又有所增加.随温度的降低薄膜的载流子浓度降低.我们还通过变温的霍尔系数估算了氮化铜薄膜的禁带宽度约为1.35eV.