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Semi-transparent perovskite solar cells have significant potential for their use in tandem solar cells with silicon (Si) or copper indium gallium selenide (CIGS) materials. Light management and optical design are important for developing a highly efficient solar cell. Herein, numerical simulation of a perovskite/silicon tandem solar cell was performed using a Matlab analytical program. The single-diode model for a solar cell is used for simulation with ideal working conditions. The tandem solar cell is comprised of two configurations which are the thin filmbased perovskite solar cell on top and a wafer-based silicon solar cell on the bottom, and the silicon sub-cell with silicon nitride (SiNx) anti-reflection coatings (ARC) in series-connected configuration. The material properties like energy bandgap, diffusion length, doping concentration are considered for calculating the device parameters. The bandgap and thickness of the perovskite material, refractive indices, photon flux, and wavelength of light are varied to calculate voltage, current, quantum efficiency, and other parameters of the tandem solar cell. The silicon sub-cell with silicon nitride (SiNx) anti-reflection coatings (ARC) in series-connected configuration decreased the reflectivity and increased the overall voltage and current of the tandem cell. The double-layer ARC films have increased the efficiency up to 1%. The efficiency of the two-terminal tandem device is found out to be over 32%. This work provides a pathway for further enhancing the power conversion efficiency of perovskite/Si tandem cells.

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Concrete is a very important composite for making different building structures to absorb different levels of radiation. Nuclear power plants, nuclear research reactors, particle accelerators and linear accelerator in medical institution use concrete in building construction. Nanoparticles or nanocrystals have different properties than their bulk counterparts. The gamma radiation absorption characteristics and beta back scattering by nanoparticles is also different than their counterparts. In this paper, carbon nanoparticles are mixed in the concrete composite during its preparation. The concrete composite with carbon nanoparticles as admixture were analyzed to provide radiation protection. The gamma radiation absorption characteristics and beta back scattering in ordinary and carbon nanoparticles contained concretes have been studied by GM counter. The results show that using carbon nanoparticles as an admixture in the concrete is one of the solutions for gamma ray shielding and beta back scattering. Therefore, it is good to use carbon nanoparticles as admixtures in concrete composites for beta and gamma radiation scattering and absorption respectively.