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

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.