Theoretical investigations on structural evolution, photoelectron spectroscopy and electronic properties of precious metal silver doped boron clusters

Abstract

The growth mechanism of borophene on silver substrates is fundamentally linked to silver-boron bonding interactions, yet the structural evolution and bonding characteristics of Ag-B clusters remain poorly understood. Here, we present a theoretical study into a range of silver-doped boron clusters using the CALYPSO cluster structural prediction method combined with density-functional theory (DFT) calculations. Global minimum searches reveal that the most AgB${}_n^{-}$ clusters possess planar or quasi-planar structures with the Ag atom clinging to the edge of the B_n moiety. Based on these ground-state structures, we successfully simulated the photoelectron spectroscopy of silver-boron clusters. The aromatic AgB${}_{18}^{-}$ cluster with a quasi-planar configuration (¹A, $C_1$) is found to exhibit the largest vertical detachment energy in the photoelectron spectra and show excellent stability. Further bonding analysis reveals that the most stable quasi-planar aromatic structure is formed by the significant interactions (3c-2e σ-bonds) between Ag and the main boron cluster, which are contributed by the Ag-5s and B-2p atomic orbitals, as well as by the presence of B-B σ-bonds within the main boron cluster. These results quantitatively establish the synergy between dative charge transfer and multicenter bonding in Ag-B systems, providing atomistic insights into borophene nucleation processes on silver surfaces. The identified structural motifs and bonding patterns lay a theoretical foundation for designing boron-based nanomaterials with tailored metal-doping configurations.