▎ 摘　　要

This work demonstrates the optical responses of the graphene coated silver-aluminum (Ag-Al) alloys' dimer in the presence of humid ambient using Discrete Dipole Approximation (DDA) as a numerical technique. The non-equivalent spherical shape of graphene coated Ag-Al alloy dimer has been considered for this study, where the plasmonic coupling supports both the bonding and anti-bonding modes which lies in higher and lower wavelength region, respectively. The combined effect of these modes provide a broad resonant spectrum, which mainly influenced by the inter-particle separation between graphene coated alloy dimer. As the interparticle separation decreases, the resonance wavelength shows a red spectral shift with increase in the magnitude of local electric field. The results of proposed geometry provide a good support for the various applications in photovoltaics and photonics.