Graphene Oxide Nanosheets-Supported ZnS Cluster Triangle Assemblies Enabling Self-Powered Solar-Blind Photodetectors With Ultrahigh Selectivity and Sensitivity

Semiconductor nanoclusters exhibit remarkable quantum confinement effects and ultranarrow size distributions, enabling highly selective absorption in the solar-blind ultraviolet (also called UVC) region, making them promising candidates for UVC photoactive materials. However, poor charge transport and disordered aggregation have severely hindered their device applications. To overcome these limitations, we developed herein a soft-template-assisted, low-temperature solvothermal method to synthesize triangular two-dimensional (2D) ZnS cluster assemblies (CTAs) with lateral dimensions of ∼100 nm, comprising uniform (ZnS)₃₄ clusters. These ZnS CTAs display a sharp, intense absorption peak at 258 nm with a steep cutoff at 268 nm, demonstrating exclusive UVC selectivity. To enhance charge transport, we integrated the ZnS CTAs with graphene oxide nanosheets (GOs) via solution mixing followed by thermal annealing to form ZnS CTAs/GOs composites. Based on these composites, we fabricated self-powered photoelectrochemical photodetectors (PEC PDs) with an averaged R_peak/R_{280 nm} rejection ratio of 80, responsivity of 21.9 mA W⁻¹, detectivity of 1.13 × 10¹² Jones, on/off ratio of 5688, surpassing all previously reported ZnS- and ZnO-based PDs. To our knowledge, this work represents the first demonstration of high-quality cluster assemblies combining exclusive UVC absorption with superior charge transport for optoelectronic applications, thereby advancing the controlled synthesis and device integration of semiconductor nanoclusters.