Bismuth Oxychalcogenide Nanosheet: Facile Synthesis, Characterization, and Photodetector Application

New 2D bismuth oxychalcogenide nanosheets have excellent theoretical properties such as high electronic mobility and excellent oxidation resistance, which have good application prospective for optoelectronic devices. In this paper, during the synthesis process via mild hydrothermal route, ammonium bismuth citrate (C6H13BiN2O7 center dot H2O) is selected as Bi source. Both Bi2O2S and Bi2O2Se nanosheets (lateral size: over 2.0 mu m, thickness: approximate to 5.0 nm) are synthesized successfully using thiourea (CH4N2S) as S source, and sodium selenite (Na2O3Se) as Se source, respectively. The as-synthesized Bi2O2S and Bi2O2Se materials have desirable nanosheet-like morphologies. After adding C6H13BiN2O7 center dot H2O, [(NH3)(2)C6H7O7](3)(-) can intercalate between the interlayers of Bi2O2S or Bi2O2Se, limiting the growth along c-axis direction, so that 2D sheets can be obtained. Finally, the photodetectors are fabricated based on Bi2O2S and Bi2O2Se films coated by thermal spraying. The experimental results show that the maximum responsivity and detectivity of Bi2O2S-based photodetector are 0.059 A W-1 and 6.77 x 10(9) Jones, respectively. As to Bi2O2Se-based photodetector, the maximum responsivity and detectivity can reach 75.14 A W-1 and 3.95 x 10(12) Jones, respectively. The mild hydrothermal synthesis using ammonium bismuth citrate as Bi source is a universal and facile method to obtain Bi2O2S and Bi2O2Se nanosheets for optoelectronic applications.