Rhma Adhiri

The fundamental characteristics of ABO3 perovskite oxides can be finely tuned by carefully substituting dopant elements at A and B sites in the lattice structure of the perovskite material. In this study, manganese (Mn) is doped into the lattice structure of BaSnO3 to study the effect of Mn incorporation on the structural, electrical, and optical properties of BaSnO3. The calculations were carried out for BaSn1−xMnxO3 for x = 0, 12.5, 25, and 37.5%. From the structural calculations, it is clear that the lattice parameter linearly decreases with an increase in Mn doping level in the BaSnO3 lattice, from 4.10 Å (x=0%) to 4.03 Å (x=37.5%). The bandgap of pure BaSnO3 is 2.76 eV. A significant decrease in the direct bandgap from 2.76 eV (x=0%) to 1.34 eV (x=37.5%) is observed. The optical absorption coefficient increases significantly, i.e., from 1.96 × 105 cm-1 to 4.79 × 105 cm-1 in the UV region and from 9 × 104 cm-1 to 3.66 × 105 cm-1 in the visible region. The current investigation, therefore, demonstrates that Mn-doped BaSnO3 is a highly promising compound for improving the efficiency of oxides intended for photovoltaic and optoelectronic applications.

Advances in materials engineering have demonstrated the high stability and low toxicity of tin-based perovskites, presenting an excellent lead-free alternative. Consequently, an ab initio study was conducted to investigate the structural, electronic, and optical properties of the tin-based perovskite oxides ASnO₃ (A = Ba, Ca, Sr, and Mg). These properties were examined using the Quantum Espresso Simulation Package (QE) with the GGA functional. The structural parameters showed highly consistent results with previous experimental and theoretical findings. The electronic calculations for BaSnO₃, CaSnO₃, SrSnO₃, and MgSnO₃ revealed semiconductor characteristics with indirect bandgaps of 3.12, 3.07, 3.2, and 0.95 eV, respectively. The total and partial densities of the states confirmed the localization of electrons within various bands. Analysis of the ASnO₃ optical properties indicated significant absorption behavior and weak reflection performance. Overall, these tin-based perovskite oxides hold outstanding potential as materials for the electronic industry, particularly in optoelectronic applications.

Myopia is one of the leading causes of visual impairment worldwide, typically beginning during the school-age years. Several factors contribute to its development, including environmental influences, excessive use of digital devices, and limited outdoor activities. The objective of this study was to assess the prevalence of myopia and associated factors among school-aged children and adolescents in rural areas of southern Morocco. A cross-sectional study was conducted between November 2022 and January 2023, involving 342 participants, with a majority of boys (54.4%) and a mean age of 13 years. Data were collected using a questionnaire that gathered sociodemographic and vision-related information, followed by a vision test to determine myopia status using cycloplegic autorefraction. The results revealed a relatively low prevalence of myopia (11%, 95% CI: 7.8%-14.4%). Multivariate logistic regression showed that a screen-watching distance less than 35 cm was significantly associated with an increased risk of myopia (OR = 1.89; 95% CI: 1.02-3.47; p = 0.042). The majority of participants (98%) reported spending at least two hours outdoors daily, and the average daily use of digital devices was 30 minutes. Interestingly, the majority of participants (72%) maintained a screen viewing distance of ≥35 cm, which was found to be associated with myopia (p = 0.04). This may reflect a behavioral adaptation rather than a direct causal relationship. Overall, the study suggests that the low prevalence of myopia in this population may be attributed to high exposure to daylight and limited use of digital devices. These findings underscore the potential protective role of outdoor activities and highlight the need for further research to better understand the factors influencing myopia development in rural populations.

Copper zinc tin sulfide (commonly known as CZTS) solar cells (SCs) are gaining attention as a promising technology for sustainable electricity generation owing to their cost-effectiveness, availability of materials, and environmental advantages. The goal of this study is to enhance CZTS SC performance by adding a back surface field (BSF) layer. SC capacitance simulator software (SCAPS) was used to examine three different configurations. Another option is to replace the cadmium sulfide (CdS) buffer layer with a titanium dioxide (TiO₂) layer. The results demonstrate that the reduced graphene oxide (rGO) BSF layer increases the conversion efficiency by 25.68% and significantly improves the fill factor, attributed to lowering carrier recombination and creating a quasi-ohmic contact at the interface between the metal and semiconductor. Furthermore, replacing the CdS buffer layer with TiO₂ offers potential efficiency gains and mitigates environmental concerns associated with the toxicity of CdS. The results of this investigation could enhance the efficiency and viability of CZTS SCs for future energy applications. However, it is observed that BSF layers may become less effective at elevated temperatures due to increased recombination, leading to reduced carrier lifetime. This study underlines valuable insights into optimizing CZTS SC performance through advanced material choices, highlighting the dual benefits of improved efficiency and reduced environmental impact.

This paper explores the challenges associated with the control of a two-stage three-phase electrical grid connected to a photovoltaic (PV) system. The objectives encompass: i) maximizing the available PV power, ii) controlling the DC-link voltage to a predetermined setpoint, and iii) considering that power quality has become an important measure in a distribution electrical network where different loads are connected, the third objective will mainly focus on ensuring power factor correction (PFC). To achieve these objectives, two loops of nonlinear controller are developed. In the outer loop, the duty cycle of a boost converter is controlled using a hybrid technique of backstepping technique and the perturb & observe (P&O) algorithm. In addition, the inner loop employs a hybrid automaton approach to tackle the challenges of a three-phase shunt active power filter (SAPF). The results have been verified through numerical simulation using MATLAB/Simulink power systems environment.

Nowadays, the world is encountering multiple challenges of energy security, economic recovery, and the effect of global warming. Investing in new fossil fuels only locks in uneconomic practices, sustains existing risks and increases the threats of climate change. In contrast, renewable energies, such as photovoltaic energy, constitute one of the most promising technologies in combating global increase in temperatures. Given its simplicity and low maintenance costs, photovoltaic energy is the most effective alternative to address the issues above. However, the standard test conditions (STCs) of PV modules are, in most cases, different from the real working conditions of a solar module. For instance, high levels of incident irradiation in an arid climate may cause the temperature of a module to rise by many degrees above the STC temperature of 25 °C, lowering the module’s performance. To effectively simulate and control PV systems for a given location, it has become paramount to develop a robust and accurate model that considers how PV modules behave. This study seeks to introduce an emerging metaheuristic optimization algorithm to estimate the unknown parameters of PV modules. The strategies deployed by flying foxes in the event of high temperatures have given birth to the development of a new metaheuristic algorithm called FFO. Contrary to previous methods, this new modeling procedure makes it possible to calculate all the parameters, regardless of temperature or irradiance. Four PV modules, having different technologies, were tested to evaluate the accuracy of the algorithm in question. The effectiveness of FFO is then contrasted with other well-known metaheuristics where single and double diode models are deployed. The results show that the FFO optimizer represents a substantial and compelling substitute for PV module extraction methods.

This paper presents a study on the fabrication and optimization of GaAs metal-insulator-semiconductor (MIS) structures, comprising Si3N4 as insulator deposited by the PECVD technique. In the RF plasma, the excitation frequencies used, are 380 KHz for the low frequency and 13.56 MHz for the higher frequency. Thanks to the established protocol, it was possible to develop several structures on n-GaAs substrate, to study effect of the surface treatment with sulfur, the deposition of the insulator by PECVD at low and high frequency, as well as the annealing of these structures. Detailed measurements of the capacitance-voltage and conductance-voltage characteristics of the MIS capacity revealed various anomalies. So, the interface properties the structures (MIS) of semiconductor GaAs with insulation metallic have been investigated. The growth of the Si3N4 layer by LF-PECVD on GaAs substrate treated with sulfur has an effect on the electrical properties of the MIS capacitys studied, leading to good capacitance-voltage (C-V) characteristics. The LF-PECVD was also effective in reducing the frequency dispersion, thus suggesting the removal of traps in n-GaAs located near the dielectric/GaAs interface. In contrast, the Si3N4 layer deposited by HF-PECVD method seems to increase the interfacial density of states near the mid-gap leading to a pinning of the Fermi level. At room temperature of measurement, a hysteresis effect was observed showing injection type effect.