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The paper presents a semi-analytical method, named the Double Legendre Polynomial Method (DLPM), which is extended for modeling the axisymmetric free vibration of a functionally graded piezoelectric (FGP) hollow cylinder resonator. The FGP resonator is composed of two-phase graded piezoelectric materials, Lead zirconate titanate (PZT4) and aluminum nitrid (AlN), on the top and bottom surfaces, respectively, where the material properties gradually change along the thickness direction. The integration of FGP materials with piezoelectric materials is an innovative aspect in material science, and this paper explores their dynamic behavior, providing insights into their mechanical and electrical properties and contributes to expand our understanding of the axisymmetric free vibration of FGP hollow cylinder resonators as a crucial factor for optimizing their performance across a wide range of applications, including sensors, actuators, energy harvesting, and structural health monitoring systems. The DLPM is applied to solve the wave governing differential equations of motion, offering a new tool for studying the dynamic behavior of FGP hollow cylinders under axisymmetric vibration. The study investigates the effects of the diameter-thickness ratio on the effective electromechanical coupling coefficient and the resonant and anti-resonant frequencies of the FGP hollow cylinder. The results show that as the diameter-thickness ratio increases, the frequency-diameter product appears to become more stable. This observation is a valuable insight for optimizing the design of these resonators. Furthermore, the study presents the electrical input admittance, the natural frequencies as well as the mechanical displacement and electric potential profiles of the resonator. All the provided results are based on the calculation of the resonant frequencies. The validity of the presented results was verified by the comparison with the existing ones reported in the literature. [ABSTRACT FROM AUTHOR]

The current paper uses the SCAPS-1D software to investigate the performance of the Al/n-ITO/n-CdS/p-Sb2Se3/p-CuS/Ni solar cell. After adjusting the simulated and experimental J–V features of the traditional ITO/CdS/Sb2Se3/Au solar cell with an efficiency of 7.6%, the influence of diverse factors such as thickness, doping, defect density in each layer, and capture cross section in Sb2Se3 and at the CdS/Sb2Se3 interface on the cell's performance is examined. The highest PCE achieved for the standard cell is 21.05% when the absorber, CdS and ITO layer thicknesses are reduced to 600 nm, 70 nm, and 100 nm, respectively, and their carrier concentrations are fixed at 5.1015, 1019, and 1019 cm−3, respectively. A new hole transport layer, consisting of inorganic copper sulfide (CuS), has been incorporated, thus improving the efficiency by blocking electrons and reducing carrier recombination. The effects of front and back contact work function, temperature, and cell resistance are also discussed. The rear-contact Ni and the front-contact Al were found to be the best arrangements with CuS HTL in the ITO/CdS/Sb2Se3 structure cell. Therefore, the optimization of the proposed Al/ITO/CdS/Sb2Se3/CuS/Ni solar structure reveals good thermal stability with a higher PCE of 23.16% for VOC, JSC, and FF of 0.761 V, 37.59 mA/cm2, and 80.97%, respectively, at 300 K. [ABSTRACT FROM AUTHOR]

The materials industry is under increasing pressure to enhance performance while lowering costs and environmental impact. Three layers of functionally graded materials (FGMs) were proposed as a solution to this problem. The general goal of this research is to develop a semi-analytical method for solving the free vibration problem of FGMs in an infinite-length composite cylinder made of stainless steel (SS) and silicon nitride (SN). The formulation is based on Legendre polynomial approach and the use of specific rectangle window functions. This approach will result in an eigenvalue/eigenvector issue in the computation of normalized frequencies and displacement profiles. The effective material properties of FGM cylinders vary following the radial direction in conformity with the power-law distribution of the volume fractions. The numerical iteration approach was generated to create data utilizing MATLAB apps to investigate the free vibration analysis from specified boundary conditions. The results are obtained for longitudinal, torsional, and flexural modes. Then, the propagation of guided waves in three-layers (SN/SS/SN) of functionally graded cylinder with diverse gradient for each mode is studied. Accordingly, the results obtained demonstrate that the volumetric fraction of the FGM cylinder is significantly impacted by the graded-index. In addition, the graded-index has a major influence on the variation of the material's properties in the radial direction. Furthermore, the dispersion curves of the normalized frequencies and phase velocities are significantly influenced by the graded-index. These results demonstrate that the phase velocities of the same mode increase as the exponents of the power-law increase. The displacement distributions are also explored to better understand the characteristics of the guiding waves inside the materials. Furthermore, the boundary conditions have a more significant influence on the normal stresses. High accuracy is found between our results and those published in the literature (error = 0.58%). This paper provides an important insight into the propagation of ultrasonic-guided waves in functionally graded multilayer cylindrical constructs for non-destructive testing. [ABSTRACT FROM AUTHOR]