Temperature and Strain Rate Dependent Anisotropic Plastic Deformation Behavior of AZ31B Mg Alloy

In the present study, the plastic deformation of commercially available AZ31B alloy at different temperatures (300K-473K) and strain rates (0.1s-1-0.01s-1-0.001s-1) under uniaxial tensile test has been carried out. Three different sheet orientations, viz., rolling direction (RD), transverse direction (TD), and 45° to rolling direction have been used. The outcomes of the experiments have demonstrated a temperature-dependent relationship between mechanical properties such as yield strength, ultimate tensile strength, and percentage elongation. The yield strength and ultimate tensile strength has decreased by 28.58% and 31.03% respectively as temperature increased from 300 K to 473 K. At elevated temperature (473 K) the material has exhibited highest ductility (64.88%) as compare to 300 K. The hardening exponent has been found to decrease with increasing temperature. The flow stress behaviour has been predicted using work hardening models such as the Hollomon and Ludwik. Two-stage work hardening behavior has been observed at all the temperatures. According to statistical parameter comparison, Ludwik equation prediction capability of correlation coefficient (0.9959) has been found to be best in agreement with the experimental results

Achieving high open circuit voltage for hole transport layer free ambient perovskite solar cells utilizing electric double layer effect

One of the features of perovskite solar cells (PSCs) that make them stand out among all photovoltaics (PVs) is their high open-circuit voltage (VOC). Owing to their simple manufacturing process, low cost of components, and good stability, carbon electrode-based metal-halide PSCs are gaining interest for their better stability and low cost than noble metal electrodes. However, carbon electrode-based hybrid PSCs suffer low open-circuit voltage (VOC). This work demonstrated the fabrication of ambient processed hybrid perovskite solar cells using low-temperature curable carbon-based electrodes without a hole transport layer. The devices exhibit an impressive high open circuit voltage of 1.07 V, even without a dedicated hole transport layer. The photovoltaic performance was further investigated with the same perovskite absorber, synthesized by solution-processed and solid-state synthesis routes. The latter have yielded better short circuit current and power conversion efficiency due to perovskite's lesser built-in trap density. Furthermore, using a combined ionic electronic carrier transport model, an electric double-layer formation was ensured across the perovskite/carbon interface and accumulating halide vacancies at the perovskite/TiO2 interface can effectively reduce carrier recombination and boost the device's VOC. This study envisages the impact of the electric double layer in free carrier transport of an ionic-electronic semiconductor like hybrid perovskites and can pave the way to improve the open-circuit voltage of carbon-based perovskite solar cells

Temperature and Strain Rate Dependent Anisotropic Plastic Deformation Behavior of AZ31B Mg Alloy

723-729In the present study, the plastic deformation of commercially available AZ31B alloy at different temperatures (300K-473K) and strain rates (0.1s-1-0.01s-1-0.001s-1) under uniaxial tensile test has been carried out. Three different sheet orientations, viz., rolling direction (RD), transverse direction (TD), and 45° to rolling direction have been used. The outcomes of the experiments have demonstrated a temperature-dependent relationship between mechanical properties such as yield strength, ultimate tensile strength, and percentage elongation. The yield strength and ultimate tensile strength has decreased by 28.58% and 31.03% respectively as temperature increased from 300 K to 473 K. At elevated temperature (473 K) the material has exhibited highest ductility (64.88%) as compare to 300 K. The hardening exponent has been found to decrease with increasing temperature. The flow stress behaviour has been predicted using work hardening models such as the Hollomon and Ludwik. Two-stage work hardening behavior has been observed at all the temperatures. According to statistical parameter comparison, Ludwik equation prediction capability of correlation coefficient (0.9959) has been found to be best in agreement with the experimental results

The emergence of concentrator photovoltaics for perovskite solar cells

The emergence of high-efficiency photovoltaic research is undergoing intense study and is technologically desirable to meet sustainable energy and environmental demand. However, every single solar cell has a theoretical power conversion efficiency limit, and, thus, without compromising the cost, the power conversion efficiency enhancement of a solar cell is highly challenging. As a convenient solution, concentrating photovoltaics can focus sunlight onto an extremely high-efficiency solar cell integrating various optics. Concentrating photovoltaics use optical devices that collect and redirect the light toward the smaller photovoltaic cell and reduce the demand for the mined elements required for the solar cell fabrication. The research interest from the photovoltaic community has concentrated on organic-inorganic hybrid halide perovskite absorbers, and nowadays, perovskite solar cells manifest their outstanding contribution among the low-cost photovoltaic technologies. Inevitably, large-area perovskite solar cells suffer a lot with their poor stability, hindering their commercialization pace. Thus, the implementation of concentrating photovoltaic technology in perovskite solar cells demonstrates an inherent advantage using a smaller size solar cell. This review provides an overview of concentrating photovoltaic technology implementation, including their recent research and development portfolio, their economic benefits in combination with inexpensive optical elements and tracking systems, limitations, challenges, and relative scope of the future study, focusing on the emerging perovskite solar cell technology