Sujuan Wu

Improvement in dye-sensitized solar cells with a ZnO-coated TiO2 electrode by rf magnetron sputtering

A surface modification method was carried out by rf magnetron sputtering to fabricate ZnO-coated TiO2 electrodes (TiO2∕ZnO) for improving the performance of dye-sensitized solar cells. The TiO2∕ZnO electrodes had been characterized by x-ray photoelectron spectroscopy, scanning electron microscopy, UV-visible spectrophotometer, and electrochemical impedance spectroscopy. The study results revealed that the TiO2 modification suppresses interfacial recombination. Sputtering ZnO for 3min on 5μm TiO2 greatly improves all cell parameters, resulting in increasing efficiency from 4.76% to 6.55%.A surface modification method was carried out by rf magnetron sputtering to fabricate ZnO-coated TiO2 electrodes (TiO2∕ZnO) for improving the performance of dye-sensitized solar cells. The TiO2∕ZnO electrodes had been characterized by x-ray photoelectron spectroscopy, scanning electron microscopy, UV-visible spectrophotometer, and electrochemical impedance spectroscopy. The study results revealed that the TiO2 modification suppresses interfacial recombination. Sputtering ZnO for 3min on 5μm TiO2 greatly improves all cell parameters, resulting in increasing efficiency from 4.76% to 6.55%.

Ultrasonic irradiation to modify the PEO/P(VDF–HFP)/TiO2 nanoparticle composite polymer electrolyte for dye sensitized solar cells

As a novel technology, ultrasonic irradiation was applied to modify the PEO/P(VDF?HFP)/TiO2 nanoparticle composite polymer electrolyte for dye sensitized solar cells (DSSCs). The ultrasonic irradiation effectively changes the rheology and the glass transition temperature and the crystallinity of the composite polymer. The experiments showed that 20?min moderate ultrasonic irradiation resulted in better penetration of the polymer electrolyte into the TiO2 nanoporous photo-anode, and the ionic conductivity was improved to 0.956?ms?cm?1 compared with 0.386?ms?cm?1 of the original polymer electrolyte. The DSSC fabricated with 20?min ultrasonic irradiation modified polymer electrolyte exhibited an improved solar energy conversion efficiency of 4.39% compared with the 3.6% of the unmodified polymer electrolyte DSSC at 30.2?mW?cm?2 light intensity.

Optimization of a quasi-solid-state dye-sensitized solar cell employing a nanocrystal?polymer composite electrolyte modified with water and ethanol

A quasi-solid-state dye-sensitized solar cell employing a poly(ethylene oxide)-poly(vinylidene fluoride) (PEO-PVDF)/TiO2 gel electrolyte modified by various concentrations of water and ethanol is described. It is shown that the introduction of water and ethanol prevents the crystallization of the polymer matrix, and enhances the free I(-)/I(3)(-) concentration and the networks for ion transportation in the electrolyte, thus leading to an improvement in conductivity. A high energy conversion efficiency of about 5.8% is achieved by controlling the additive concentration in the electrolyte. Optimization of the additive-modified electrolyte performance has been obtained by studying the cross-linking behavior of water and ethanol with Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and viscosity measurements, and the electrical conduction behavior of the electrolyte with impedance spectra measurements.

Effect of thickness on structural, electrical, and electrochemical properties of platinum/titanium bilayer counterelectrode

To strengthen the adhesion of platinum layer to counterelectrodes of dye sensitized solar cells, titanium thin film has been utilized as adhesion layer between platinum and substrate [Wei et al., Appl. Phys. Lett. 90, 153122 (2007)]. In our study, platinum/titanium bilayer counterelectrodes were fabricated by magnetron sputtering. The structural, electrical, and electrochemical properties of the bilayer counterelectrode were studied by varying the thickness of both platinum and titanium layers. The influence of both electrochemical active surface and crystallite size on charge transfer resistance of the bilayer counterelectrode was explored. From these evaluations, it was found that the as-prepared titanium layer was almost amorphous, and intermetallic phase was formed between platinum and titanium layers. As expected, sheet resistance of the electrode decreased with the increase in deposition time of both platinum and titanium layers. Metal titanium was found to be inert in the catalyzing reduction in tr...