Probing the weak interaction between silver and boron.

Understanding the boron-coinage-metal interactions is critical for understanding the nucleation and growth mechanisms of borophene on coinage-metal substrates. Binary metal-boron clusters provide ideal models for obtaining atomic-level information about the metal-boron interactions. Here we report an investigation of the structure and bonding of the AgB cluster as a model system to gain insight into the interaction of boron with silver, the most inert substrate to grow borophene. Photoelectron spectroscopy reveals that the spectra of AgB resemble those of bare B , suggesting extremely weak chemical interactions between Ag and boron. Quantum calculations show that AgB ( , A') consists of a B borozene weakly interacting with a Ag atom on its edge. Chemical bonding analyses find that the Ag atom interacts with the B motif primarily through its 5s orbital with little perturbation to the structure and bonding of the B borozene. Compared to CuB and AuB , Ag is found to have the weakest interaction with B, consistent with the fact that silver substrates are the most inert for borophene syntheses.