Zhao Yulong

Synthesis and application of TiO2 single-crystal nanorod arrays grown by multicycle hydrothermal for dye-sensitized solar cells

TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned TiO2 nanorod arrays (NRs) are grown on the fluorine-doped tin oxide (FTO) substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED). It is found that dye-sensitized solar cells (DSSCs) assembled by the as-prepared TiO2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.

Preparation and Characterization of Co 3 (PO 4 ) 2 /Ag 3 PO 4 Nanocomposites for Visible-Light Photocatalysis

采用简单的化学偏聚法合成出Ag3PO4纳米颗粒、磷酸钴（Co3（PO4）2,CoP）纳米片以及它们两者的纳米复合结构（CoP/Ag3PO4）,同时还比较了它们的可见光催化活性.采用场发射扫描电镜（FESEM）、X射线衍射（XRD）、紫外-可见（UV-Vis）吸收光谱以及光致发光谱等手段对其形貌、结构、光学以及可见光催化性能等进行表征.结果表明,CoP/Ag3PO4复合纳米结构的可见光降解甲基橙（MO）的速率和循环稳定性均明显优于其它两种物质.这表明CoP应该起着共催化剂的作用,它能够抑制光生电子与空穴之间的复合,并且提供大量高活性的光生空穴.此外,我们还发现CoP/Ag3PO4降解另一种阳离子型染料——罗丹明B（RhB）的能力则远不如纯Ag3PO4,这可能是与光催化剂的表面性质发生改变有关,造成更低的RhB吸附能力.本文提供了一种廉价制备高效可见光催化剂的新方法.In this study, Ag3PO4 nanoparticles (NPs), cobalt phosphate (Co3(PO4)2, CoP) nanosheets (NSs), and their composites (CoP/Ag3PO4) were synthesized via a facile chemical precipitation method. Their visiblelight photocatalytic activities were compared and investigated. The structural, morphological, optical, and visiblelight photocatalytic properties of the prepared samples were characterized by X-ray diffraction (XRD), fieldemission scanning electron microscopy (FESEM), ultravioletvisible (UVVis) diffuse absorbance and photoluminescence (PL) spectroscopies. We found that both the degradation rate and cyclical stability of the CoP/Ag3PO4 hybrids increased significantly under visible-light irradiation when methyl orange (MO) was used as the target with reference to single-phase Ag3PO4 NPs or CoP NSs. This suggests that CoP might play a cocatalyst role, which suppresses carrier recombination and provides a large number of photogenerated holes. Additionally, we also observed that the CoP/Ag3PO4 hybrids hardly degraded Rhodamine B (RhB), a cationic dye. This behavior might be attributed to the lower amount of dye molecule absorption because of a change in surface polarity. We thus present a new approach for the development of low-cost and visible-light responsive photocatalysts.

A Comparable Study on the Arrays of Aligned ZnO Nanowires and TiO2 Nanotubes for Applications of Dye-sensitized Solar Cells

Abstract Vertically aligned ZnO nanowire array (NWA) was synthesized on the transparent conductive substrates by a facile hydrothermal method. Then, TiO 2 nanotube array (NTA) was obtained by a successive treatment of the ZnO NWA. Moreover, two dye-sensitized solar cells (DSSCs) were fabricated using these samples as the photoanodes in order to investigate their photoelectrochemical performance. It is found that TiO 2 NTA demonstrates a power conversion efficiency of ∼0.81%, which is three times higher than ZnO NWA. The DSSC devices were used with a simple diode model to evaluate the current-voltage ( J - V ) curves. Finally, it was revealed that the cell performance improvement is attributed to an increased shuttle resistance and a suppressed leakage current.

Laser-Induced Damage Threshold of TiO2 Films with Different Preparation Methods and Annealing Temperatures

Sol-gel TiO2 films are prepared by the dip-coating method and the spin-coating method, and then annealing is performed at different temperatures. The structures, optical properties, surface morphologies, absorption and laser-induced damage threshold (LIDT) at 1064 nm and 12 ns of the films are investigated. The results show that the dip-coating method can be used to obtain a higher LIDT than the spin-coating method. When the annealing temperature increases from 80°C to 120°C, the dip-coated film obtains a higher LIDT, whereas the spin-coated film obtains a lower LIDT. In addition, the damage morphology is a spalling pit for the dip-coated film annealed at 80°C. When the annealing temperature increases to 120°C, it shows a melting area. For both the spin-coated films annealed at different temperatures, the damage morphologies are the combination of spalling and melting. The differences in LIDT and damage morphologies of the films are discussed.