Huang Guangsheng

Stability of Dye Solar Cells with Photoelectrode on Metal Substrates

In this study, the stability of dye solar cells DSCs with different kinds of metals as the photoelectrode substrate is studied.Stainless steels StSs, Inconel, and titanium substrates were tested to find stable substrate options. Photovoltaic characterization,electrochemical impedance spectroscopy EIS, scanning electron microscopy, and substrate polarization measurements were usedin the characterization. DSCs based on different grades of StS suffered from rapid degradation of efficiency within few hours inlight soaking. Good stability was demonstrated with DSCs with Inconel and Ti photoelectrode substrates. The Inconel substrateshave a thick passive oxide layer, which is likely related to good stability. However, according to the EIS analysis, the oxide layerof Inconel substrates increased resistive losses, which caused a lower fill factor and photovoltaic efficiency compared to theTi-based cells.© 2010 The Electrochemical Society. DOI: 10.1149/1.3374645 All rights reserved.Manuscript submitted December 17, 2009; revised manuscript received February 19, 2010. Published April 21, 2010.

Electrochemical Performance of AZ31 Magnesium Alloy under Different Processing Conditions

Abstract In order to select a good cost-performance ratio magnesium alloy as anode material, the electrochemical properties of AZ31B magnesium alloy under different processing conditions were investigated by electrochemical workstation, optical microscope (OM), scanning electron microscopy (SEM) and energy dispersed spectroscopy (EDS). Extruded, rolled, cast-rolled and as-cast AZ31 magnesium alloys were prepared as the anode materials. The results show that under different processing conditions, the extruded alloy is the best cost-performance ratio anode material among the four alloys. It possesses the most negative equilibrium potential, the lowest corrosion current density and the smallest free corrosion rate indicating the highest electrochemical activity due to the uniform fine grains and the second phase. Its corrosiun products are loose, dispersing uniformly on the extruded anode surface, prone to falling off which decrease the polarization and increase the utilization of the anode. The electrochemical activity and the corrosion resistance of the rolled and the cast-rolled alloys are relatively low, compared with the extrude samples. Due to the coarse grains, as-cast defects and coarse second phase distributed along the grain boundaries, the as-cast alloy has unstable discharge curve and positive discharge potential. The corrosions of AZ31 magnesium alloy under different conditions are almost pitting corrosion.