Textile based dye-sensitized solar cells with natural dyes

Natural dyes extracted from hibiscus petals, elderberries and mallow flowers were investigated in dye-sensitized solar cells. Two approaches were followed: 1. Hybrid glass/fabric cells with titanium dioxide on glass as working electrode and a textile counter electrode; 2. hybrid fabric/glass cells with zinc oxide as working electrode on textile and a glass counter electrode. The zinc oxide layer on cotton was prepared by electroless deposition whereas the titanium dioxide coated glass electrodes were obtained directly from the manufacturer. In both cases the redox couple consisted of iodine / triiodide and the counter electrode was based on an electrically conductive fabric

Effects of deposition time and counter-electrode size on the fabrication of lscf-sdc carbonate composite cathode for sofc

The electrophoretic deposition (EPD) process has shown great potential in the development of cathodes for solid oxide fuel cell (SOFC). This study thus aimed to determine the feasibility of the electrophoretic deposition technique in producing composite cathode films. Two parameters were investigated, namely, the effects of counter electrode size and those of deposition time on the thickness and quality of an LSCF-SDC carbonate cathode composite deposited onto an SDC carbonate substrate. The effects of the changed parameters were observed by applying constant suspension pH and voltage. Five different deposition times ranging from 10 to 30 min were selected. The counter electrode sizes used were 25 × 25 mm2 and 50 × 50 mm2 . Then, the cathode composite films were sintered at 600°C for 90 min. Microstructural characterization and film thickness measurement were performed using a scanning electron microscope (SEM). The 50 × 50 mm2 counter electrode was found to produce a cathode composite film with higher thickness. The effects of the selected parameters (deposition time and counter electrode size) were also determined by analyzing the weight and thickness of the obtained LSCF-SDC carbonate films. The results showed that for the selected time interval, a film thickness of 4.6 to 30.8 μm is generated. Further studies on fabricating LSCF-SDC carbonate cathode composites by electrophoretic deposition present promising potential given that the film thickness obtained agree well with those derived in previous studies on various types of cathode materials

Simulation and measurement of melting effects on metal sheets caused by direct lightning strikes

Direct lightning strikes melt metal parts of various systems, like fuel and propellant tanks of rockets and airplanes, at the point of strike. Responsible for this melting are the impulse current and, if occurring, the long duration current, both carrying a remarkable charge Q. For studying these meltings the simulation in the laboratory has to be based on the parameters of natural lightnings. International standards exist defining certain threat levels of natural lightnings and giving possible generator circuits for the simulation. The melting caused by both types of lightning currents show different appearance. Their characteristics, their differences in melting and heating of metal sheets are investigated. Nevertheless the simulation of lightning in the laboratory is imperfect. While natural lightning is a discharge without a counter electrode, the simulation always demands a close counter electrode. The influence of this counter electrode is studied

Particulate counter electrode system for enhanced light harvesting in dye-sensitized solar cells

A particulate counter electrode with photo scattering and redox catalytic properties is applied to dye sensitized solar cells (DSSCs) in order to improve photo conversion efficiency and simplify the assembly process. Our particulate counter electrode acts as both a photo reflecting layer and a catalyst for reduction of electrolyte. The reflective and catalytic properties of the electrode are investigated through optical and electrochemical analysis, respectively. A short circuit current density enhancement is observed in the DSSCs without the need to add an additional reflecting layer to the electrode. This leads to a simplified assembly process. (C) 2013 Optical Society of Americ

Preparation of a Counter Electrode with P

This study investigates the applicability of a counter electrode with a P-type semiconductor oxide (such as NiO) on a dye-sensitized solar cell (DSSC). The counter electrode is fabricated by depositing an NiO film on top of a Pt film, which has been deposited on a Fluorine-doped tin oxide (FTO) glass using an ion-sputtering coater (or E-beam evaporator), using a simple spin coating method. This study also examines the effect of the average thickness of TiO2 film deposited on a working electrode upon the power conversion efficiency of a DSSC. This study shows that the power conversion efficiency of a DSSC with a Pt(E)/NiO counter electrode (4.28%) substantially exceeds that of a conventional DSSC with a Pt(E) counter electrode (3.16%) on which a Pt film was deposited using an E-beam evaporator. This result is attributed to the fact that the NiO film coated on the Pt(E) counter electrode improves the electrocatalytic activity of the counter electrode

BaFe_{1.8}Co_{0.2}As_2 thin film hybrid Josephson junctions

Josephson junctions with iron pnictides open the way for fundamental experiments on superconductivity in these materials and their application in superconducting devices. Here, we present hybrid Josephson junctions with a BaFe_{1.8}Co_{0.2}As_2 thin film electrode, an Au barrier and a PbIn counter electrode. The junctions show RSJ-like current-voltage characteristics up to the critical temperature of the counter electrode of about 7.2K. The temperature dependence of the critical current, IC, does not show an Ambegaokar-Baratoff behavior. Well-pronounced Shapiro steps are observed at microwave frequencies of 10-18GHz. Assuming an excess current, I_ex, of 200 {\mu}A at 4.2K we get an effective I_C R_N product of 6 {\mu}V.Comment: submitted to Appl. Phys. Let

Low-Cost Flexible Nano-Sulfide/Carbon Composite Counter Electrode for Quantum-Dot-Sensitized Solar Cell

Cu2S nanocrystal particles were in situ deposited on graphite paper to prepare nano-sulfide/carbon composite counter electrode for CdS/CdSe quantum-dot-sensitized solar cell (QDSC). By optimization of deposition time, photovoltaic conversion efficiency up to 3.08% was obtained. In the meantime, this composite counter electrode was superior to the commonly used Pt, Au and carbon counter electrodes. Electrochemical impedance spectra further confirmed that low charge transfer resistance at counter electrode/electrolyte interface was responsible for this, implied the potential application of this composite counter electrode in high-efficiency QDSC

Observation of the Josephson effect in Pb/(Ba,K)Fe2As2 single crystal junctions

We have fabricated c-axis Josephson junctions on single crystals of (Ba,K)Fe2As2 by using Pb as the counter electrode in two geometries, planar and point contact. Junctions in both geometries show resistively shunted junction I-V curves below the Tc of the counter electrode. Microwave induced steps were observed in the I-V curves, and the critical currents are suppressed with an in-plane magnetic field in a manner consistent with the small junction limit. ICRN products of up to 0.3 mV have been observed in these junctions at 4.2 K. The observation of Josephson coupling along the c-axis between (Ba,K)Fe2As2 and a conventional superconductor suggests the existence of a s-wave superconducting order parameter in this class of iron pnictide superconductors.Comment: 16 pages and 3 figure

Enhancing DSSC conversion efficiency by ozone-treated TiO2 photoanode and optimum CNT/PDDA counter electrode

The conversion efficiency of dye-sensitized solar cells (DSSCs) depends on the performance of the photoanode and the counter electrode. In this paper, UV-ozone treatment has been applied to the photoanode to clean and increase the hydrophilicity of the photoanode. As a result, the dye adsorption capacity was improved. Also, low-cost multiwalled carbon nanotube (CNT) combined with poly (diallyl dimethylammonium chloride) (PDDA) was used to fabricate the counter electrode. The CNT/PDDA counter electrode was optimized to maximize its performance. By using the ozone-treated photoanode and optimum CNT/PDDA counter electrode, the conversion efficiency has increased by about 64%

Non-linear electrical actuation and detection

A method and system is disclosed to detect and analyze an electric signal based on movement between an element and a counter electrode influenced by a nonlinear electric field produced by an electrical signal impressed between the element and counter electrode. Through detection of changes in the distance between the element and the counter electrode characteristics of the element and/or the environment of the element may be ascertained. Changes in the distance between the element and the counter electrode may be monitored based on changes in the value of capacitance between the element and counter electrode. The disclosed devices and methods may be employed to detect, for instance, presence of chemical/biological species in a sample or measure physical parameters of a sample such as pressure/acceleration, density, viscosity, magnetic force, temperature, and/or extremely small masses