Band Alignment in In‐Oxo Metal Porphyrin SURMOF Heterojunctions

Abstract Tailoring band alignment at donor–acceptor interfaces is critical for optimizing charge separation and exciton dynamics in optoelectronic materials. Herein, a first‐principles study of Indium‐oxo surface‐mounted metal organic frameworks (SURMOFs) based on tetratopic free‐base and metalated tetrakis(4‐carboxyphenyl)porphyrin (TCPP) linkers is presented, wherein band edge positions are systematically tuned via porphyrin core metalation without altering the crystal structure. Using density functional theory (DFT) and simplified Tamm‐Dancoff Approximation (sTDA) calculations, the electronic structure and optical absorption properties are evaluated across a library of metal centers (H + , Ni 2+ , Zn 2+ , Pd 2+ , Pt 2+ , [In(OH) 2+ ]). By combining distinct linkers within a periodic simulation cell, model heterostructures are constructed that exhibit either type‐I or type‐II band alignment, enabling exciton confinement or spatial charge separation, respectively. Furthermore, multi‐heterojunction configurations incorporating three different metal centers demonstrate the feasibility of constructing energy cascades for directional exciton funneling and controlled charge extraction. These results establish porphyrin metalation as a modular strategy for engineering band offsets in SURMOF‐based heterostructures for photochemical and optoelectronic applications.