Theoretical insights into PtSSe–SnSSe heterostructures for renewable energy applications

Abstract

We present a comprehensive study on the structural, dynamical, electronic, and catalytic properties of PtSSe–SnSSe van der Waals heterostructures (vdWHS), classified into four distinct configurations based on the interaction between chalcogen atoms at the interface. Structural optimization and phonon analyses confirm the stability of all configurations, with the S–S configuration exhibiting strong binding energy and high dynamical stability. Charge transfer analysis reveals significant electron transfer at the interface, leading to a unique interfacial charge distribution and enhanced polarization, which promote efficient charge separation. Electronic structure calculations reveal indirect band gaps and type-II alignment across all configurations, with the Se–S interface having the smallest bandgap (0.31 eV). Many-body perturbation theory-based GW calculations further show that the heterostructure formation substantially reduces the exciton binding energy of the constituent monolayers, enabling improved electron–hole separation. Our findings highlight the Se–S configuration as the most promising for photocatalytic and photovoltaic applications. These insights into interfacial interactions, polarization effects, and band alignments underscore the potential of PtSSe–SnSSe vdWHS as efficient energy materials for renewable energy technologies.