A new two-dimensional material B2S2 has been successfully synthesized for the first time and validated using first-principles calculations, with fundamental properties analyzed in detail. B2S2 has a similar structure as transition-metal dichalcogenides (TMDs) such as MoS2, and the experimentally prepared free-standing B2S2 nanosheets show a uniform height profile lower than 1 nm. A thickness-modulated and unique oxidation-level dependent band gap of B2S2 is revealed by theoretical calculations, and vibration signatures are determined to offer a practical scheme for the characterization of B2S2. It is shown that the functionalized B2S2 is able to provide favorable sites for lithium adsorption with low diffusion barriers, and the prepared B2S2 shows a wide band photoluminescence response. These findings offer a feasible new and lighter member for the TMD-like 2D material family with potential for various aspects of applications, such as an anode material for Li-ion batteries and electronic and optoelectronic devices.
Keywords: boron disulfide; first-principles calculations; material synthesis; potential applications; two-dimensional materials.