Structure of Cu-Phthalocyanine Vacuum Deposited on Inclined Glass Substrates

Cu-phthalocyanine is widely studied as a hole-transport layer in organic electronic devices. Since Cu-phthalocyanine is a molecular solid, the crystal structure depends on a circumstance to a great extent. Vacuum deposited layers were known to consist of two consecutive layers. In this article, Cu-phthalocyanine was deposited on the glass substrate inclined at several angles. The thickness of the first layer was found to be dependent on the substrate angle.

Pt Deposition on Anode Enhances the Performance of Dye-Sensitized Solar Cell with Non-Cross-Linked Gel Electrolyte

We fabricated dye-sensitized solar cells with non-cross-linked fluorinated gel electrolyte. The application of fluorinated gel to electrolyte is a challenging issue at present. The gelation of the electrolyte is of importance in order to solve the problem in the durability of the cell. We investigated, in this article, the effect of Pt deposition on the anode of the cell. The Pt was deposited by means of a DC sputtering technique. The studies showed that the deposition time strongly affected both open voltage and short-circuit current of the cell. The adaptive thickness of the Pt layer was determined to be 10 nm for the non-cross-linked fluorinated gel electrolyte cells.

Electrode for Force Sensor of Conductive Rubber

Tactile sensors are believed to be a key element in order to realize robotic fingers to catch a fragile object without damage. Force sensitive conductive rubber is a low-cost material and then attractive for the application to tactile sensors. We have studied the effect of electrodes attached to the rubber sheets. We have tried four kinds of electrodes: vacuum deposited Al, adhesive Cu tape, Al thin film sheet and silver paste. It can be concluded that vacuum deposited Al has the highest potential from the practical point of view;it has the widest dynamic range and good precision at the same time.

Effect of Parameters on Potential Induced Degradation of Solar Cell

Solar cells are widely used to generate electric energy even at homes. It surely has a great advantage of sustainability. However, the potential induced degradation has been found to be an obstacle problem for practical use. It was reported that the main cause is the dielectric breakdown in the glass covered over the solar cells triggered by the thunderstroke. In this paper, the effects of the parameters such as the position of thunderstroke, the wave form, the peak value and the front duration of the lightning current, were examined by means of numerical calculation. For the lightning current, a step-like waveform and an impulse waveform were examined. The effect of the induced voltage was found to be independent of the waveform. The peak value, the front duration of the lightning current greatly affects the induced voltage.

A Sputtering Deposition of Al Enhances the Output Reproducibility in a Conducting Rubber Force Sensor

Compressive force sensors or pressure sensors are indispensable to tactile sensors in humanoid robots. It is investigated that low-cost electro-conducting rubber sheets are applied to the force sensor, of which the biggest problem is its poor reproducibility. It was found that the aluminum deposition by a vacuum evaporation method shows excellent characteristics but suffers deterioration by a radiation heating effect. The aluminum electrode was deposited by a sputtering method, known to have an advantage of a low-temperature method, and the reproducibility of the output was improved.

ZnO Films Deposited on Glass by Means of DC Sputtering

ZnO films were deposited on glass substrates by means of a direct current (DC) sputtering technique. The physical properties of the films were investigated on the basis of X-ray diffraction measurements. It was found that as-deposited films show c-axis oriented crystal normal to the surface with the extension of c axis by 1.27% that is estimated from the shift of the peak in the X-ray diffraction pattern. Post-deposition annealing in air at higher than 400℃ eliminates the shift and sharpens the diffraction peak structure at the same time. The electrical resistivity continues to decrease from 500 Ω•cm down to 0.6 Ω•cm by annealing as high as 600℃.

Stacked Structure Improves Output Reproducibility of Rubber Force Sensor

The electricity-conducting rubber force sensor is an attractive candidate as a low-cost material for tactile sensors. This article shows the evidence that the output reproducibility is largely improved when two identical sheets of the sensors are stacked. The stacked structure may reduce accidental error that is a fatal obstacle in an accurate control system.

Addition of Pyridine to Dye-Sensitized Solar Cell Including Fluorinated Oligomer Gel Electrolyte

Fluorinated oligomer gel is suitable to the electrolyte of dye-sensitized solar cell for low cost production. In this article, addition of pyridine was investigated for the purpose of enhancing the short current density. Two kinds of ionic liquids were tested: imidazolium and pyrazolium systems. The two different stages of adding pyridine to the electrolyte were considered and the amount of pyridine was studied. It was found that the electrolyte including pyrazolium ionic liquids to which pyridine was added before the mixing with fluorinated oligomer showed the highest electric conductivity, short current density and open voltage. This resulted in the highest conversion efficiency of 4%. As the amount of pyridine increased, the fill factor and the open voltage were improved at first, and then the short current density increased. If the pyridine was added more, the short current density conversely decreased.

Electric Conductivity of Fluorinated Oligomer Gel Electrolyte Including Ionic Liquid and Performance of Dye Sensitized Solar Cell

Fluorinated oligomer gel is suitable to the electrolyte of dye sensitized solar cell. This article studied mainly in the scope of electric conductivity, including ionic liquid in the electrolyte. It was found that the ratio of mixing with dimetyl sulfoxide and the concentration of LiI affect the conductivity. The behavior is different depending on the type of ionic liquid. Although the mixing ionic liquid enhances the conductivity, the short circuit current density of assembled solar cell with it was suppressed so much.

Structural Analysis of ZnO Film Deposited by Means of Metal Organic Decomposition Method

ZnO films were deposited on glass substrates by means of a metal organic decomposition (MOD) method. We investigated the effect of annealing temperature, time and the number of laminated layers on the film structure on the basis of X-ray diffraction measurements. We found the optimum conditions of the temperature and the time to be 600°C and 40 minutes for the preparation, respectively. In addition, the layer-by-layer forming was not found to degrade the film from viewpoint of X-ray line width.

Dye-Sensitized Solar Cell with Fluorinated Gel Electrolyte: Effect of TiO₂Particle Size on Performance

We fabricated dye-sensitized solar cells including fluorinated gel electrolyte and studied about the relationship between the performance of the solar cells and the aggregation state of TiO2 nano-particles on electrodes. As for the performance of the cell, the I-V characteristics were measured under irradiation. The combination of TiO2 nanoparticles with different size plays an important role in bringing unevenness to realize a large surface area, which is critical for the high performance of the cells.

Response to Applied Voltage to Polyurethane Soft Actuators with Loaded Weights

We are investigating a polymer soft actuator using a poly urethane elastomer film that bends by an applied voltage, which is based on the electrostriction. In this article, the bending magnitude was studied in a weight-loaded condition. It was found that the thinner film can bend the more without any load, but that the film of 200-μm thickness gave the largest bending when weights were loaded. The thickness of some degree is critical for large bending torque.

Simulation Suggests Origin of Potential Induced Degradation of Solar Cell

Solar cells are well known as devices for sustainable electric energy generation. Nowadays the potential induced degradation has been brought up as an obstacle problem for practical use. In order to determine the cause of this kind of degradation, numerical simulation by a finite difference time domain method has been performed for computational electromagnetics in the case that the thunder attacks the solar modules. The results show that the dielectric breakdown in the glass covered over the solar cells triggered by the thunderstroke is critical. So it is helpful to protect the dielectric breakdown in the glass from the thunderstroke.

Electrode Effects on Polyurethane Soft Actuator

A polymer soft actuator is under investigation using a poly urethane elastomer film that bends by means of an applied voltage, which is based on the electrostriction. Bending experiments were performed under different metal electrodes deposited the both sides of the film. Even if the thickness of the both electrodes?is the same, the metal of the both electrodes?is desirable to be the same to bend more. It is suggested that the balance of the physical properties of the both metal is critical for larger bending.

Electrodeposition of Bi-Sb alloy using Cu electrodes

Bi-Sb alloys were grown by means of an electrodeposition method using Cu electrodes. The alloys were studied with the help of an x-ray diffractometer and an electron probe microanalysis. The both investigations have shown no trace of Cu in the obtained alloys. It can be concluded that Cu electrodes can be used for the deposition of Bi-Sb alloys;which results in an advantage of availability of the electrode.

Conducting Rubber Force Sensor: Transient Characteristics and Radiation Heating Effect

Compression force sensors are indispensable to tactile sensors in humanoid robots. We are investigating the application of low-cost electrically conducting rubber sheets to force sensors, of which the biggest problem is its poor reproducibility. We have found that the deposition of aluminum by a vacuum evaporation method shows such an excellent characteristic that the sensor can be used in a wide range under 10.33 N/cm2. In this article, we investigated time response of the sensors and also studied how the radiation heating during the vacuum evaporation process for Al deposition affected their sensing property. We found that the radiation heating induces deterioration from the point of view of standard deviation of the output voltage of the sensors at a transient region. We convince that a low-temperature Al deposition method should be developed to form electrodes on the electrical conducting rubber sensors.

ZnO Films Deposited on Porous Silicon by DC Sputtering

ZnO is now a fascinating semiconductor oxide material for light emission or transparent electronic conductors. We deposited ZnO films on porous silicon, which is known as a light emitting material based on silicon, by means of a direct current sputtering technique. The deposition was performed at room temperature, and the samples were annealed afterwards to improve the ZnO crystalline quality. The discussion to compare our results with that formed on Si wafer, reveals that the ZnO on porous silicon has the better crystalline quality in the scope of an X-ray diffraction measurement.

Comparison between Amorphous and Tandem Silicon Solar Cells in Practical Use

Solar cells are now widely used as a clean method for electric energy generation. Among various type of solar cells, we compared the ability between amorphous and tandem (amorphous and polycrystalline) silicon solar cells by means of simultaneous running test. This kind of comparison is of importance practically, because the comparison of only inherent characteristics cannot include environmental parameters such as temperature totally. It was concluded that both types of solar cells provided almost the same energy for one year. The amorphous silicon solar cell provided more energy in summer while the tandem solar cell was advantageous in winter. It is due to the fact that the decrease in energy conversion at the higher cell temperature is more noticeable in tandem solar cells.

Acetylacetone-Based Electrolyte in Dye Sensitized Solar Cell

Dye sensitized solar cells attract much attention for a clean energy generation device. Among several solvents for the electrolyte, we investigated here the cell characteristics with acetylacetone as a solvent. The electric conductivity of the electrolyte increases as the concentration of polyethylene glycol (PEG) decreases or that of ionic liquid increases. The addition of pyridine into the electrolyte improves both the open voltage and the short current density. On the other hand, the replacement of PEG with fluorinated oligomer in the gel electrolyte highly increases the short current density where the open voltage is not varied. As the concentration of ionic liquid increase, the open voltage and the short current density gradually increase. When more than 20 wt.% of the ionic liquid was mixed, the gelation was not obtained. As a result, acetylacetone is a practical solvent for a gel electrolyte with the fluorinated oligomer and ionic liquid.