Plasmonic Hot Hole Transfer in Gold Nanoparticle-Decorated Transition Metal Dichalcogenide Nanosheets

This work studies photogenerated carrier dynamics in gold nanoparticle (AuNP)-decorated mono- to few-layer transition metal dichalcogenide (TMD) nanosheets using transient absorption spectroscopy (TA). TA unveiled the presence of a long-lived photoinduced absorption (PIA) feature in both MoSe₂ and WSe₂ decorated with covalently bound AuNPs. This long-lived PIA feature emerges only from direct Au interband excitation in AuNP-decorated MoSe₂ and WSe₂; it does not manifest from intraband excitation nor in AuNP-decorated MoS₂ or WS₂. Based on X-ray/ultraviolet photoelectron spectroscopy and previous theoretical studies, it is proposed that this PIA signature arises from hot hole transfer from the AuNP to the adjacent TMD, producing a charge-separated state. This suggests charge separation at the metal–semiconductor interface may be used to extend the lifetime of interband excitation generated hot holes. This development could represent an important advance in harnessing plasmonic dissipation pathways to generate long-lived carriers suited for solar-driven light harvesting and catalysis.