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A double Legendre polynomial quadrature-free method was presented to analyze axisymmetric free vibration problem for axially polarized Functionally Graded Piezoelectric circular plates. The present analytical method directly incorporated the boundary conditions into the vibration control equation. At the same time, the mechanical displacements and the electrical potential were defined as the form of double Legendre polynomials series. Then, the solution of eigenvalue was used to obtain the resonant/anti-resonant frequencies. In view of including lots of time-consuming integration calculations, the quadrature-free process was deduced to improve the computational efficiency. The valid of the presented method was verified by the comparison with the existing literature and the commercial software COMSOL. Furthermore, the effects of the material gradient index, radius-thickness ratio on the frequencies, and electro-mechanical coupling efficient were studied. The results showed that the frequency-radius product tends to be stable with the increase of the radius-thickness ratio, and the increase of gradient index led to the increase of the frequency-radius product. [ABSTRACT FROM AUTHOR]

Inorganic solar cells based on the binary-type metal chalcogenide semiconductor, particularly Sb 2 Se 3 , have recently garnered significant interest due to their abundant and nontoxic natural elements, strong thermal stability, and favorable optoelectronic properties. Single-absorber solar cells using antimony selenide have been the most common choice to date but have shown only limited efficiency in converting sunlight into electricity. The primary aim of this research is to examine a device structure that demonstrates an enhanced efficiency. The study explores the potential of utilizing CZTGSe as a secondary absorber layer to enhance photovoltaic performance metrics. The basic solar cell structure studied is FTO/CdS/Sb 2 Se 3 /Cu 2 O/Au, which has a power conversion efficiency of 24.94%. By conducting simulations using SCAPS-1D, an in-depth analysis of the proposed dual-absorber structure (FTO/WS 2 /Sb 2 Se 3 /CZT 0.2 G 0.8 Se/Cu 2 O/Au) was carried out. Solar cell efficiency was enhanced through the adjustment of the Ge concentration in the secondary CZTGSe absorber with various electron transport layers (CdS, ZnSe, WS 2 , and ZnOS). The findings indicate that optimal efficiency is achieved at a Ge concentration x = 0.8, with WS 2 emerging as the most effective among the proposed ETLs. The physical characteristics of the layers, including their thickness, doping density, and impurity level, as well as the interfaces, were then modified to improve device performance. The photovoltaic device achieves a fill factor of 88.31%, a V OC of 1.117 V, a J SC of 38.23 mA/cm 2 , and an efficiency of 37.76% when all factors are perfectly optimized. This study proposes that CZTGSe has the potential to be utilized in creating a stable, cost-efficient Sb 2 Se 3 solar device with high efficiency.