Unveiling the Effect of Interfacial Structure on Hot Carrier Dynamics in Ag/ZnS Heterostructures through Interface Engineering

The enhancement of plasmon-induced hot carrier injection efficiency in metal/semiconductor heterostructures is essential for boosting their photoelectronic performance. Nevertheless, the considerable lattice mismatch between the components hinders the development of clearly defined interfacial atomic structures, complicating the understanding of the interfacial structure's impact on hot carrier dynamics. Here, we demonstrate a ligand-assisted chemical transformation strategy to produce high-yield (>90%) epitaxial Ag/ZnS heterostructures from matchstick-like Ag₂S/ZnS templates. It is found that the presence of a ligand promotes preferential nucleation of Ag nuclei at the interface, leading to well-defined interfacial structures. Comparative studies reveal that epitaxial interfaces in Ag/ZnS heterostructures significantly improve plasmon-induced hot electron transfer from Ag to ZnS under 520 nm excitation, achieving a quantum yield of 38.12%, nearly double that of nonepitaxial counterparts (21.11%), as quantified by near-infrared transient absorption pump-probe spectroscopy. Additionally, single-particle photothermal microscopy measurements demonstrate that the photothermal signals of epitaxial Ag/ZnS heterostructures display a uniform distribution with a decreased intensity compared to those of their counterparts, further correlating plasmonic heating characteristics of the heterostructures with their interfacial structure. This work establishes the importance of interfacial engineering in optimizing plasmon-induced hot carrier dynamics, offering insights into the design of high-performance optoelectronic devices utilizing plasmonic metal/semiconductor heterostructures.