Ligand-Amplified Quantum Tunneling in Polymer-Mediated Artificial Photosystems

Abstract

Quantum tunneling offers a fascinating paradigm for orchestrating spatial charge transport in artificial photosynthesis. However, precisely manipulating electron tunneling across well-defined heterointerfaces remains a formidable challenge, with conventional designs largely confined to classical Semiconductor-Insulator-Metal (S-I-M) architectures. Herein, we report a conceptual endeavor by fundamentally departing from the traditional S-I-M model, constructing a unique and novel Semiconductor-Insulator-Ligand/Metal tunneling platform. Specifically, an ultrathin insulating poly(sodium 4-styrenesulfonate) (PSS) layer is engineered onto a transition metal chalcogenide (TMC, e.g., CdS) substrate. Subsequently, poly(diallyldimethylammonium chloride) (PDDA)-capped metal nanocrystals (M@PDDA, M = Au, Pd) are precisely anchored via electrostatic self-assembly, yielding well-defined TMC@PSS@M@PDDA heterostructures. Distinct from conventional systems, the PDDA ligands synergistically couple with the metal core to form an integrated, highly potent electron capture center driven by the Schottky-junction effect. This unique synergistic driving force triggers non-classical, directional electron tunneling from the photoexcited TMC substrate directly through the insulating PSS barrier. Benefiting from this advantageous Quantum tunneling, TMC@PSS@M@PDDA heterostructures demonstrate significantly enhanced and multifarious visible-light-driven photoredox activities including selective organic transformations and H2O2 production. This work establishes an elegant conceptual paradigm for decoding and customizing quantum tunneling pathways, offering profound fundamental insights into advanced solar energy conversion.