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Multijunction or tandem solar cells can split the solar spectrum over several subcells with different bandgaps to transform the sunlight into electricity more effectively than single-junction solar cells. The monolithic tandem design of third generation silicon solar energy materials is auspicious for photovoltaics.In this paper, the Simulation-based studies of copper zinc tin sul de/Silicon (CZTS/Si) tandem cells based on CZTS as an upper subcell and silicon as a lower subcell absorber layer have been performed using SCAPS-1D. This study aims to evaluate the CZTS tandem cells' performance based on the fact that both subcells are simulated to produce the best e ciency recorded at its bandgap. The Simulation and optimization of the single junction CZTS and Si solar cells were initially performed to t the state-of-art records e ciency of 11.65% and 18.7%, respectively. Further, both the upper and lower cell has evaluated at different thicknesses for tandem con guration after validation. Also, to obtain the current matching condition for tandem structure, the upper subcell's performance is investigated at different thickness ranges from 0.1 µm -1 µm while keeping the lower subcell thickness at 80µm. Thus, at optimized upper absorber thickness of 0.191 µm and lower subcell 80 µm at transmitted spectrum the current matching condition obtained and gave an e ciency of 10.6% and 11.9%, respectively. The maximum e ciency of ~ 23 is obtained for tandem design with enhancing open circuit voltage 1.4 V.

BACKGROUND: The finite element method (FEM) is an efficient and powerful tool for studying human spine biomechanics. OBJECTIVE: In this study, a detailed asymmetric three-dimensional (3D) finite element (FE) model of the upper cervical spine was developed from the computed tomography (CT) scan data to analyze the effect of ligaments and facet joints on the stability of the upper cervical spine. METHODS: A 3D FE model was validated against data obtained from previously published works, which were performed in vitro and FE analysis of vertebrae under three types of loads, i.e. flexion/extension, axial rotation, and lateral bending. RESULTS: The results show that the range of motion of segment C1–C2 is more flexible than that of segment C2–C3. Moreover, the results from the FE model were used to compute stresses on the ligaments and facet joints of the upper cervical spine during physiological moments. CONCLUSION: The anterior longitudinal ligaments (ALL) and interspinous ligaments (ISL) are found to be the most active ligaments, and the maximum stress distribution is appear on the vertebra C3 superior facet surface under both extension and flexion moments.

Multijunction or tandem solar cells can split the solar spectrum over several subcells with different bandgaps to transform the sunlight into electricity more effectively than single-junction solar cells. The monolithic tandem design of third generation silicon solar energy materials is auspicious for photovoltaics. In this paper, the Simulation-based studies of copper zinc tin sulfide/Silicon (CZTS/Si) tandem cells based on CZTS as an upper subcell and silicon as a lower subcell absorber layer have been performed using SCAPS-1D. This study aims to evaluate the CZTS tandem cells' performance based on the fact that both subcells are simulated to produce the best efficiency recorded at its bandgap. The Simulation and optimization of the single junction CZTS and Si solar cells were initially performed to fit the state-of-art records efficiency of 11.65% and 18.7%, respectively. Further, both the upper and lower cell has evaluated at different thicknesses for tandem configuration after validation. Also, to obtain the current matching condition for tandem structure, the upper subcell's performance is investigated at different thickness ranges from 0.1 µm -1 µm while keeping the lower subcell thickness at 80µm. Thus, at optimized upper absorber thickness of 0.191 µm and lower subcell 80 µm at transmitted spectrum the current matching condition obtained and gave an efficiency of 10.6% and 11.9%, respectively. The maximum efficiency of ~ 23 is obtained for tandem design with enhancing open circuit voltage 1.4 V.

Copper zinc tin sulfide (CZTS) and copper zinc tin sulfo selenide (CZTSSe) kesterite minerals are nontoxic and abundant in the earth with the promise of cost-effective photovoltaic applications. This study explains a tandem solar cell made of kesterite materials that can capture sunlight over a broad spectrum. The tandem solar cell under consideration consists of a wide bandgap CZTS thin-film upper subcell and an underlying narrow bandgap CZTSSe-based lower subcell. To begin with, SCAPS-1D was employed to model the experimental CZTS- and CZTSSe-based solar cells to fit the simulated and experimental results. Additionally, adding a back surface field (BSF) layer, a modification of the back contact, testing at different thicknesses, and doping of both subcells absorber layer result in improving the open-circuit voltage (Voc) to a maximum of 1.5 V, which led to an exceptional tandem solar cell efficiency of 23.99% at current matching circumstances. Furthermore, how light radiation power and temperature variations impact the proposed solar cell performance is being investigated. This study provides significant insights into the efficient tandem solar cell design and manufacture.