Improvement in Strain Sensor Stability by Adapting the Metal Contact Layer

Research on stretchable strain sensors is actively conducted due to increasing interest in wearable devices. However, typical studies have focused on improving the elasticity of the electrode. Therefore, methods of directly connecting wire or attaching conductive tape to materials to detect deformation have been used to evaluate the performance of strain sensors. Polyaniline (PANI), a p-type semiconductive polymer, has been widely used for stretchable electrodes. However, conventional procedures have limitations in determining an appropriate metal for ohmic contact with PANI. Materials that are generally used for connection with PANI form an undesirable metal-semiconductor junction and have significant contact resistance. Hence, they degrade sensor performance. This study secured ohmic contact by adapting Au thin film as the metal contact layer (the MCL), with lower contact resistance and a larger work function than PANI. Additionally, we presented a buffer layer using hard polydimethylsiloxane (PDMS) and structured it into a dumbbell shape to protect the metal from deformation. As a result, we enhanced steadiness and repeatability up to 50% strain by comparing the gauge factors and the relative resistance changes. Consequently, adapting structural methods (the MCL and the dumbbell shape) to a device can result in strain sensors with promising stability, as well as high stretchability.

Conduction Band Offset Effect on the Cu2ZnSnS4 Solar Cells Performance

Among the causes of the degradation of the performance of kesterite-based solar cells is the wrong choice of the n-type buffer layer which has direct repercussions on the unfavorable band alignment, the conduction band offset (CBO) at the interface of the absorber/buffer junction which is one of the major causes of lower VOC. In this work, the effect of CBO at the interface of the junction (CZTS/Cd(1-x)ZnxS) as a function of the x composition of Zn with respect to (Zn+Cd) is studied using the SCAPS-1D simulator package. The obtained results show that the performance of the solar cells reaches a maximum values (Jsc = 13.9 mA/cm2, Voc = 0.757 V, FF = 65.6%, ɳ = 6.9%) for an optimal value of CBO = -0.2 eV and Zn proportion of the buffer x = 0.4 (Cd0.6Zn0.4S). The CZTS solar cells parameters are affected by the thickness and the concentration of acceptor carriers. The best performances are obtained for CZTS absorber layer, thichness (d = 2.5 µm) and (ND = 1016 cm-3). The obtained results of optimizing the electron work function of the back metal contact exhibited an optimum value at 5.7 eV with power conversion efficiency of 13.1%, Voc of 0.961 mV, FF of 67.3% and Jsc of 20.2 mA/cm2.

Dark Current and Magnetic Field in Liquid

The dark electric current arising from the contact of aluminum with clean water decreases with an increase in the induction of the external magnetic field. Changing the distance between the source of the magnetic field and the aluminum electrodes makes it possible to determine the region of formation of the dark current. It turns out that this occurs in the area of liquid-metal contact where the curvature of the electrodes is maximal.

Intact metal/metal halide van der Waals junction enables reliable memristive switching with high endurance

Organic-inorganic or inorganic metal halide materials have emerged as a promising candidate for a resistive switching material owing to its capability to achieve low operating voltage, high on/off ratio and multi-level switching. However, the high switching variation, limited endurance and poor reproducibility of the device hinder practical use of the memristors. Here, we report a universal approach to relieve the issues by using a van der Waals metal contacts (vdWC). By transferring the pre-deposited metal contact onto the active layers, an intact junction between the metal halide and contact layer is formed without unintended damage in the active layer that has been caused by a conventional physical deposition process of the metal contacts. Compared to the thermally evaporated metal contact (EVC), the vdWC did not degrade optoelectronic quality of the underlying layer to enable memristors with reduced switching variation, significantly enhanced endurance and reproducibility relative to those based on the EVC. By adopting various metal halide active layers, versatile utility of the vdWC is demonstrated. Thus, this vdWC approach can be a useful platform technology for development of high-performance and reliable memristors for future computing.

Using low cost materials for highly efficient eco-friendly FASnI3 based solar cell with Cu2O as HTM and TiO2 as ETM with different metal contacts

Perovskite materials are considered the mainstay of PV manufacturing asoutstandingto notable optoelectronic properties. In this work the act of Pb-free FASnI3 based PSC, TiO2 as ETL, and Cu2O as HTL and Ag,Au, Pt,are the different metal contact is simulated using SCAPS software. Here we focused on the impactparameters of device such as the thickness of the Ab-Layer, doping level ofperovskite layer and different working temperature. Additionally, we investigated the effect of different metal contact and their work function. The simulated results show that a perovskite layer thickness of 350nm for good perovskite solar cell. For optimizing parameters, efficiency 18.10%, FF 78.14, Jsc 29.61, and Voc 0.7821 have been achieved for Cu2O and TiO2 respectively. The thermal study shows that device configurations for this present work at 300k it is stable for this entire work.

Counter-rotating electric generator for wind power plants with liquid metal energy transfer

The problem of creating effective structures that ensure mutual rotation of the rotor and stator of an electric generator. The wide practical application of counter-rotor wind-electric generators, which provide a significant increase in specific power, is hindered by the disadvantages and low reliability of existing systems for removing electric energy from the windings of a rotating counter-rotor, due to the dry friction mode. It is possible to increase the reliability of the contact removal of electrical energy from the counter rotor (rotating stator) by replacing solid brushes with liquid metal contact groups, which will lead to a certain increase in the resistivity of the contact group, compensated by the contact area of the liquid metal with the contact ring. It is most advisable to use liquid metal contact groups based on gallium, which will raise the permissible temperature limit of operation by about 2 times compared to the achieved level to 275 °C and, thereby, additionally raise the specific power of the electric generator.