Preparation of Ultrathin Two‐Dimensional TixTa1−xSyOz Nanosheets as Highly Efficient Photothermal Agents

Although two‐dimensional (2D) metal oxide/sulfide hybrid nanostructures have been synthesized, the facile preparation of ultrathin 2D nanosheets in high yield still remains a challenge. Herein, we report the first high‐yield preparation of solution‐processed ultrathin 2D metal oxide/sulfide hybrid nanosheets, that is, Ti x Ta 1− x S y O z ( x =0.71, 0.49, and 0.30), from Ti x Ta 1− x S 2 precursors. The nanosheet exhibits strong absorbance in the near‐infrared region, giving a large extinction coefficient of 54.1 L g −1 cm −1 at 808 nm, and a high photothermal conversion efficiency of 39.2 %. After modification with lipoic acid‐conjugated polyethylene glycol, the nanosheet is a suitable photothermal agent for treatment of cancer cells under 808 nm laser irradiation. This work provides a facile and general method for the preparation of 2D metal oxide/sulfide hybrid nanosheets.