Precise defect control is pivotal for advancing nanomaterial performance, yet layered metal chalcogenides are plagued by coupled, multidimensional defects that degrade their electronic, optical, and chemical functions. Here, we introduce a guest-mediated defect healing (GMDH) strategy that concurrently heals multidimensional defects in layered chalcogenides under mild conditions. In a cascade process, hydrothermally synthesized SnS2 nanosheets undergo vacuum-sealed annealing that expels intercalated guest molecules (e.g., thioacetamide), driving interlayer lattice rearrangement; simultaneously, thermal decomposition of these guests further replenishes sulfur vacancies. This one-route treatment avoids external sulfur sources and high temperatures, lowering defect density while improving crystal integrity and carrier transport. As a proof of concept, GMDH-treated SnS2 enables trace NO2 detection under high humidity with fast and reversible response (response time = 64 s), strong humidity tolerance (up to 90% RH), and long-term operational stability (180 days under 75% RH), directly linking simultaneous defect repair to device robustness. GMDH provides a general and scalable pathway for precision defect engineering in two-dimensional layered chalcogenides and underscores their promise for humidity-resilient, reliable electronic and sensing technologies.
Li et al. (2026) studied this question.