Core-shell nanomaterials provide a versatile platform for tuning physical properties and integrating complementary functionalities in nanoscale systems, but their synthesis often requires multistep procedures and precise control over composition, morphology, and interfaces. Achieving core-shell architectures in nanosheets is particularly challenging due to the difficulty of controlling growth direction and interfacial formation. Here, we describe a one-step chemical exfoliation process that produces core-shell nanosheets from the highly air-sensitive compound Li1+x MnTe2. Brief sonication in Milli-Q water under ambient conditions yields a dark gray suspension of nanosheets within 10 min, which remains stable in air for at least 31 days. Powder X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, and transmission electron microscopy indicate the formation of few-layer crystalline Mn-(OH)2 cores encapsulated by amorphous Te-O shells. Magnetic measurements show antiferromagnetic ordering in the restacked nanosheets. The suspension can be readily deposited onto coated glass, polyethylene terephthalate, and Si/SiO2 substrates to form uniform films, with electrical transport measurements indicating resistances on the order of megaohms at room temperature. These results demonstrate chemical exfoliation as an effective approach for producing core-shell nanosheets with magnetic and electronic functionality.
Yuan et al. (Tue,) studied this question.