First-principles investigation of two-dimensional trichalcogenide and sesquichalcogenide monolayers

We have used density functional theory to investigate the dynamical stability and the electronic structure of several new semiconducting two-dimensional single layers, with chemical compositions such as ABX₃ and A₂X₃.  The calculated interlayer binding energies and the absence of imaginary states in the phonon spectra indicate the possibility to isolate them in the form of a single layer. Also, the calculated band edges reveal that some of these two-dimensional materials are promising candidates for water-splitting applications.