These findings can be utilized as basic knowledge for the development of synthesis methods to obtain suitable core-shell NPs for future applications. Core-shell upconversion nanoparticlemetal-organic framework (UCNPMOF) nanostructures are constructed by coating hexagonal NaYF4 :Yb,Er nanoparticle (NP) cores with amino-functionalized iron carboxylate MOF shells. The calculated results suggest that different Fe-core sizes, Ag-shell thickness, and shapes in core-shell configuration NPs influence the tunning and enhancement of absorption spectra. The 30 nm core-size and aspect ratio of 3 is optimized for high sensitivity and figure of merit (FOM). Furthermore, prolate nanostructure shows the shifting of LSPR peaks at λ max towards the longer wavelength regime as compared to spherical shape nanostructures. It is observed that the LSPR peaks are blue-shifted with increasing core-sizes and red-shifted with the increasing shell thickness as well as the aspect ratio. The absorption localized surface plasmon resonance (LSPR) peak at the maximum wavelength (λ max.) of core-shell nanoparticles (NPs) is found in the range of 335–387 nm & 382–749 nm wavelengths for sphere & prolate nanostructures respectively. A displacement reaction produces a protective, noble metal shell around nanoparticles or microparticles, for example a copper shell around cobalt nanoparticles. The Fe-core is coated with varying Ag-shell thicknesses for different shapes and sizes of nanoparticles. A method is disclosed for synthesizing core-shell nanoparticles or microparticles in an aqueous solution. In this work, the optical properties of Fe-Ag nanoparticles in core-shell configuration are studied by using the discrete dipole approximation (DDA) method. The core-shell nanoparticles have received much attention due to their potential applications in biomedicine, molecular detection, catalyst, and cancer therapy. Computational Simulation of Gold Core/Shell Nanostructures for Near-Field Transducers in Heat-Assisted Magnetic Recording.