Quasiparticle electronic structure of phthalocyanine:TMD interfaces from first-principles $GW$

Interfaces formed between monolayer transition metal dichalcogenides (TMDs) and (metallo)phthalocyanine molecules are promising in energy applications and provide a platform for studying mixed-dimensional molecule-semiconductor heterostructures in general. An accurate characterization of the frontier energy level alignment at these interfaces is key in the fundamental understanding of the charge transfer dynamics between the two photon absorbers. Here, we employ the first-principles substrate screening $GW$ approach to quantitatively characterize the quasiparticle electronic structure of a series of interfaces: metal-free phthalocyanine (H$_2$Pc) adsorbed on monolayer MX$_2$ (M=Mo, W; X=S, Se) and zinc phthalocyanine (ZnPc) adsorbed on MoX$_2$ (X=S, Se). Furthermore, we reveal the dielectric screening effect of the commonly used $\alpha$-quartz (SiO$_2$) substrate on the H$_2$Pc:MoS$_2$ interface, using the dielectric embedding $GW$ approach. Our calculations furnish the first set of $GW$ results for these interfaces, providing structure-property relationship across a series of similar systems and benchmarks for future experimental and theoretical studies.