ABSTRACT
The controlled and efficient formation of oxygen vacancies on the surface of metal oxide semiconductors is required for their use in gas sensors. This work addresses the gas-sensing behaviour of tin oxide (SnO2) nanoparticles for nitrogen oxide (NO2), NH3, CO, and H2S detection at various temperatures. Synthesis of SnO2 powder and deposition of SnO2 film is conducted using sol-gel and spin-coating methods, respectively, as these methods are cost-effective and easy to handle. The structural, morphological, and optoelectrical properties of nanocrystalline SnO2 films were studied using XRD, SEM, and UV-visible characterizations. The gas sensitivity of the film was tested by a two-probe resistivity measurement device, showing a better response for the NO2 and outstanding low-concentration detection capacity (down to 0.5 ppm). The anomalous relationship between specific surface area and gas-sensing performance indicates the SnO2 surface's higher oxygen vacancies. The sensor depicts a high sensitivity at 2 ppm for NO2 with response and recovery times of 184 s and 432 s, respectively, at room temperature. The result demonstrates that oxygen vacancies can significantly improve the gas-sensing capability of metal oxide semiconductors.
ABSTRACT
As a promising solar absorber material, antimony selenide (Sb2Se3) has gained popularity. However, a lack of knowledge regarding material and device physics has slowed the rapid growth of Sb2Se3-based devices. This study compares the experimental and computational analysis of the photovoltaic performance of Sb2Se3-/CdS-based solar cells. We construct a specific device that may be produced in any lab using the thermal evaporation technique. Experimentally, efficiency is improved from 0.96% to 1.36% by varying the absorber's thickness. Experimental information on Sb2Se3, such as the band gap and thickness, is used in the simulation to check the performance of the device after the optimization of various other parameters, including the series and shunt resistance, and a theoretical maximum efficiency of 4.42% is achieved. Further, the device's efficiency is improved to 11.27% by optimizing the various parameters of the active layer. It thus is demonstrated that the band gap and thickness of active layers strongly affect the overall performance of a photovoltaic device.
ABSTRACT
In this work, a new wide-band-gap n-type buffer layer, ZnSe, has been proposed and investigated for an antimony selenide (Sb2Se3)-based thin-film solar cell. The study aims to boost the Sb2Se3-based solar cell's performance by incorporating a cheap, widely accessible ZnSe buffer layer into the solar cell structure as a replacement for the CdS layer. Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) simulation software is used to thoroughly analyze the photovoltaic parameters of the heterojunction structure ZnSe/Sb2Se3. It includes open circuit voltage (V OC), short-circuit current density (J SC), fill factor (FF), power conversion efficiency (PCE), and external quantum efficiency (EQE). The absorber layer (Sb2Se3) thickness is adjusted from 0.5 to 3.0 µm to perfect the device. In addition, the influence of cell resistances, radiative recombination coefficient, acceptor and donor defect concentration in the Sb2Se3 layer, and interface defects of the ZnSe/Sb2Se3 layer on overall device performance are investigated. The ZnSe buffer layer and the Sb2Se3 absorber layer are designed to have optimal thicknesses of 100 nm and 1.5 µm, respectively. The proposed device's efficiency with optimized parameters is calculated to be 24%. According to the simulation results, it is possible to build Sb2Se3-based thin-film solar devices at a low cost and with high efficiency by incorporating ZnSe as an electron transport layer.
ABSTRACT
This theoretical investigation's primary goal is to investigate how the Sb2Se3 solar cell's performance may be improved. Here, SnTe, as an innovative back surface field (BSF) layer, has been added between the rear contact (Mo) and absorber layer (Sb2Se3). Above the absorber layer, the structure comprises a thin CdS buffer layer. For each layer of the Al/CdS/Sb2Se3/SnTe/Mo structure, the physical characteristics such as the active layer's thicknesses, carrier concentration, defect density, and rear electrode's work function are determined. The suggested cell outperformed the solar cell without the SnTe layer, which had an efficiency of 20.33%, with enhanced efficiency and open-circuit voltage (Voc) of 28.25% and 0.86 V, respectively, at 300 K. The above solar cell used 0.15 µm SnTe layer, 0.05 µm CdS, and 2.0 µm Sb2Se3 layer. The features of the antimony selenide (Sb2Se3) based solar structure is examined using the SCAPS-1D software, which simulates solar cells in one dimension. Investigations have also been done into how working temperatures influence the I-V parameters of the structure.
ABSTRACT
BACKGROUND: We sought to compare treatment satisfaction with inhaled medications among asthmatics using a metered-dose inhaler (MDI) or a dry-powder inhaler (DPI), and to correlate satisfaction with treatment adherence, pulmonary function, and airway inflammation. METHODS: Spirometry, fraction of expired nitric oxide (FENO), and asthma control were assessed in 200 adult subjects with asthma (69 men, 131 women) using MDI or DPI. Treatment satisfaction with inhaled therapy was assessed with the Treatment Satisfaction Questionnaire for Medication (TSQM) in 4 domains: Effectiveness, Side Effects, Convenience, and Global Satisfaction. The Medication Adherence Questionnaire (MAQ) was used to evaluate adherence to treatment. RESULTS: There were 115 and 85 subjects with asthma, using MDI and DPI, respectively. More MDI users (40.9%) had well-controlled asthma as compared to DPI users (17.6%). MDI users had greater treatment adherence and better TSQM domain scores for Effectiveness, Convenience, and Global Satisfaction than did DPI users. Multivariate linear regression analysis revealed no significant association between MDI/DPI use and TSQM domain scores. TSQM Convenience and Global Satisfaction domain scores were significantly correlated with MAQ scores (Spearman's coefficients 0.211 and 0.218, P = .003 and P = .002, respectively). There was no significant correlation between any TSQM domain score and pulmonary function or FENO concentration. CONCLUSIONS: MDIs were associated with better disease control and treatment adherence among subjects with asthma. Both MDI and DPI are likely to provide equivalent treatment satisfaction.
