Preparation of In 2 S 3 and Cu-Doped In 2 S 3 2D Ultrathin Nanoflakes with Tunable Absorption and Intense Photocurrent Response

We reported an effective method to synthesize In2S3 and Cu-doped In2S3 two-dimensional ultrathin nanoflakes by the hydrothermal method through tuning the Cu/In molar ratio. The transmission electron microscope images showed that the products had ultrathin flake-like shape with wrinkling and rolling. The X-ray diffraction patterns indicated the crystal phase of nanoflakes was varied from β-In2S3 to tetragonal-CuInS2 as the Cu/In molar ratio was increased. The In2S3 nanoflakes exhibited absorption band at 450 nm, while new absorption peaks in turn appeared at 550 nm and 670 nm as the Cu/In molar ratio was increased. In addition, the two-dimensional ultrathin nanoflakes exhibited intense photocurrent response.