One-pot synthesized Bi₂Te₃/graphene for a self-powered photoelectrochemical-type photodetector

Bismuth telluride (Bi₂Te₃) is a typical topological insulator, which possesses a narrow band gap and exhibits fascinating performance in the photodetector field. In this work, we fabricated a Bi₂Te₃/graphene heterostructure via a facile one-pot hydrothermal method. The as-prepared composites were used as the electrode materials for the photoelectrochemical (PEC)-type photodetector. From the results of PEC tests, we obviously found that the Bi₂Te₃/graphene heterostructure offers a remarkable improvement in photoresponse compared to that of sole Bi₂Te₃, and effectively demonstrates effective photocarrier generation and transfer at the interface between the graphene and Bi₂Te₃, which can enhance the properties of the photoresponse. Moreover, owing to the self-powered ability of the PEC-type photodetector, it can work under the bias potential of 0 V and exhibits a prominent photoresponse which can reach 2.2 mA W⁻¹. Also, the photocurrent density of the prepared Bi₂Te₃/graphene heterostructure-based photodetector can almost linearly rise with the increased irradiation power density. Even if the light intensity was reduced to 40 mW cm⁻², the photocurrent density could also reach 67 μA cm⁻², which ensures the photodetection ability of the as-prepared Bi₂Te₃/graphene under low light intensity. The excellent performance of a Bi₂Te₃/graphene heterostructure for a PEC-type photodetector holds great promise in the field of photoelectric detection. (paper)