Photoelectrochemical self-powered photodetector based on 2D Liquid-Exfoliated Bismuth nanosheets: With novel structures for portability and flexibility

Abstract Bismuth as an element of group VA (P, As, Sb, Bi), which is considered as beyond graphene materials, has attracted much attention because of its stable topological insulator properties. Herein, photoelectrochemical (PEC)-type photodetector based on two-dimensional bismuth nanosheets was designed and fabricated. By using a solid electrolyte to replace the traditional electrolyte, we have achieved a novel structure to make the device more portable. Besides that, due to the solid/liquid heterojunction, which generates an built-in electric field that can separate electron hole pairs effectively, this type of photodetector possess self-powered ability, and it exhibited preferable photoresponsivity which is about 0.5 μA W−1 without external bias potential; meanwhile, the rise time of the photodetector is about 3.3 s and decay time is about 1.8 s. Moreover, we used the flexible indium-tin oxide (ITO) as the substrate; the prepared device can work under the bending states. The novel structure and the excellent properties of the fabricated self-powered flexible PEC-type photodetector make it more promising in the optical detection field.