Facile fabrication and characterization of two-dimensional bismuth(iii) sulfide nanosheets for high-performance photodetector applications under ambient conditions

Abstract

Two-dimensional (2D) bismuth(iii) sulfide (BiS) nanosheets as non-toxic graphene-like nanomaterials were successfully fabricated by a facile liquid phase exfoliation (LPE) method. A robust photodetector employing a BiS nanosheet film has been fabricated for the first time via a facile fabrication process on an ITO-coated glass. UV-Vis and Raman spectroscopy techniques were carried out and they confirmed the inherent optical and physical properties of BiS nanosheets. Photoelectrochemical (PEC) measurements demonstrate that a significantly higher photocurrent density (42 μA cm) and enhanced photoresponsivity (210 μA W), at a lower bias potential in alkaline solution, of the BiS nanosheet-based photodetector are achieved, compared with those of other 2D nanomaterial-based photodetectors under light irradiation. Furthermore, the as-prepared BiS nanosheet-based photodetector not only exhibits an appropriate capacity of self-driven broadband and high-performance photoresponse but also displays strong long-term stability of the ON/OFF switching behaviour without any external protection in alkaline solutions. Because of facile synthesis via a LPE method, a higher photocurrent density and photoresponsivity, self-driven performance and long-term stability of the BiS nanosheet-based photodetector at a lower bias potential in alkaline solutions, the present work can provide fundamental acknowledgement of the high performance of this new kind of PEC-type 2D nanosheet-based photodetector.

Enhanced Photodetection Properties of Tellurium@Selenium Roll‐to‐Roll Nanotube Heterojunctions

“…The 1000 switching cycles with 5 s ON/OFF intervals were traced (Figure A–C), and 900th–950th cycles were selected to evaluate the stability of Te x @Se y (Figure D–F). P ph s of the fresh samples gradually decrease with the test time in these three electrolytes (Figure A–C), similar to the trends of Te nanosheets, Bi quantum dots, and Bi 2 S 3 nanosheets . This can be attributed to the insufficient immersion in the aqueous electrolyte for the fresh samples, confirmed by the quite stable signal for the sample after storing in electrolytes for one month.…”

Engineering Vacancies in Bi2S3yielding Sub‐Bandgap Photoresponse and Highly Sensitive Short‐Wave Infrared Photodetectors

“…All the values were achieved at drain bias of 1 V and zero gate voltage. It is noted that the responsivities are much higher by several orders of magnitude compared to previously reported Bi 2 S 3 photodetectors and the spectral coverage has been extended to short‐wave infrared range due to formation of in‐gap states in sulphur defective samples. Besides, we also measured the gate‐dependent photocurrent and responsivity of both detectors (Figure S4, Supporting Information), which shows that the backgate does not have appreciable influence on the photodetection performance suggesting the photoconductive effect as the underlying photodetection mechanism …”

“…For example, the Bi 2 S 3 nanorods and nanoflowers showed a photo‐switching ratio of only 23.6 . The nanosheet‐based near infrared detectors exhibited responsivity ranging from 210 µA W −1 to 4.4 A W −1 . Bi 2 S 3 CQDs have been demonstrated with relatively high responsivity up to 200 A W −1 due to the long‐lived hole traps providing a gain mechanism .…”

Self‐Powered Photodetectors Based on 2D Materials

“…A series of characterizations found that the InSe nanosheets prepared were mostly 7 and 8 layers, and had large lateral dimensions, as shown in Figure b. The PEC‐type photodetectors based on few‐layer InSe nanosheets exhibited satisfactory photocurrent density photoresponsivity, and good self‐powered photodetection behavior with a photocurrent density of 16.6 nA cm −2 at 0 V. In addition, Huang et al prepared 2D Bi 2 S 3 nanosheets by a simple liquid phase stripping method and fabricated PEC‐type photodetectors based on Bi 2 S 3 nanosheets on ITO‐coated glass (Figure c). PEC measurements show that the PEC photodetectors based on Bi 2 S 3 nanosheets have good photoresponse characteristics and self‐powered light detection characteristics in alkaline solution; they have a light responsivity of 8.9 µA W −1 in a 0.1 m KOH solution at a bias of 0 V. In addition, the photoresponse performance of the Bi 2 S 3 ‐based PEC‐type photodetector can be adjusted with electrolyte concentration and external bias, and its photoresponsivity increases to 210 µA W −1 in 1 m KOH solution at 0.6 V bias.…”

“…c) Schematic diagram of the photodetector based on Bi 2 S 3 nanosheets. Reproduced with permission . Copyright 2018, The Royal Society of Chemistry.…”