Figure 1 Schematic diagram of the CdS/ZnO/Ti nanostructured solar cell. The photovoltaic performance was characterized under an AM 1.5 G filter at 100 mW/cm2 using a Newport Oriel 94022A Solar Simulator (Model 94022A, Newport, OH, USA), as calibrated using a certified OSI standard silicon photodiode. A
sourcemeter (2400, Selleckchem NCT-501 Keithley Instruments Inc., Cleveland, OH, USA) was used for electrical characterization during the measurements. Results and discussion Morphology and crystal structure of the nanostructured photoanodes The employed weaved titanium wire is flexible and of a diameter of about 85 μm with quite smooth surface. The color of the weaved titanium wire changed from gray to white after the deposition of ZnO nanosheets. Figure 2a shows the typical FESEM images of ZnO nanosheet arrays grown on weaved titanium wires. The surface of the titanium cylinder wires is covered totally and uniformly with ZnO nanosheet arrays, which would provide a large area for the deposition of CdS nanoparticles. Figure 2b Trichostatin A shows the cross-sectional
SEM image of ZnO nanosheets. It is apparent that all products consist of a large number of well-aligned sheet-like nanostructures. The SEM image clearly indicates that the film is constructed by assembling nanosheets in a compact way and the nanosheets are vertically oriented to the surface of titanium wires with different angles to each other. The average film thickness is about 8 to 10 μm. Figure 2c,d shows the top view of the ZnO nanosheets and CdS/ZnO nanostructures at a high magnification, respectively. The space www.selleckchem.com/products/AG-014699.html between nanosheets presents an
easily accessed open structure for the deposition of CdS nanoparticles, which is very important aminophylline for the performance of solar cells. Furthermore, this open structure could provide an easy filling of electrolyte into the space between the nanosheets and is beneficial to hole diffusion from CdS nanoparticles to counter electrode. By comparing Figure 2c,d, it can be clearly seen that the CdS nanoparticles were uniformly deposited onto ZnO nanosheets. The CdS nanoparticles make direct contact with the ZnO nanosheet surface, forming a firm connection on the ZnO nanosheets with a type II heterojunction, which may greatly enhance charge transport, charge separation, and overall photocurrent efficiency of the solar device. Figure 2 Typical FESEM images of ZnO nanosheets on weaved titanium wire substrate. (a) The low-magnification and (c) high-magnification FESEM images of ZnO nanosheets. (b) The cross-sectional view of ZnO nanosheets. (d) ZnO nanosheets deposited with CdS nanoparticles for 20 cycles. XRD patterns of ZnO/Ti and CdS/ZnO/Ti nanostructures are shown in Figure 3.