Photoinduced Electron Transfer in a MoS₂/Anthracene Mixed-Dimensional Heterojunction in Aqueous Media

Mixed-dimensional (0D/2D) van der Waals heterojunctions were constructed by physical adsorption of anthracene (Anth) onto few-layer MoS₂ nanosheets. The physical modification of few-layer MoS₂ nanosheets using anthryl dendron 1, i.e., a poly(amidoamine) dendrimer having an anthracene core, via a simple yet efficient exfoliation approach afforded MoS₂/1 hybrids, which are stable for at least one month. The emission quenching typical for anthracene is also observed in the MoS₂/anthracene mixed-dimensional heterojunctions. Transient absorption measurements on MoS₂/1 hybrids proved that photoinduced electron transfer occurs at the MoS₂/anthracene interface. The lifetime of the singlet excited state (τ_S1(¹Anth*)) for MoS₂/1 was evaluated to be 4.1 ns, which is shorter than that of anthryl dendron 1 (13 ns). Interestingly, a remarkably long lifetime was observed for the anthracene cation radical (6.1 ¯s). Relatively long lifetimes of charge-separate states of MoS₂/1 hybrids would be beneficial design features for efficient photovoltaics, photocatalysts, and related optoelectronic applications.