Electronic Structure of Mixed-Dimensional Heterojunctions from Optimally-Tuned Range-Separated Hybrid Functionals

Mixed-dimensional heterojunctions (MDHJ) comprised of molecules deposited on 2D materials are actively being explored for optoelectronic applications. A predictive theory of the electronic structure of MDHJ is challenging due to their numerous competing energy scales, including local and non-local electronic correlations, interfacial charge transfer and orbital hybridization. Here we study the electronic structure of 0D-2D (metallophthalocyanines-MoS₂) heterojunctions by density functional theory calculations, using optimally tuned range-separated hybrid functionals. This new method allows for optimally and non-empirically tuning the range-separation parameters for accurate description of both short-range and long-range electron interactions, as well as including the dielectric screening effect from electrostatic model. We obtain electronic structures in good agreement with known experimental results, and show the importance of phthalocyanine non-frontier orbitals in tuning the interface properties.