Architectured Bi2S3 nanoflowers: photoenhanced field emission study

In the present investigation, we demonstrate a facile hydrothermal/solvothermal route to fabricate elegant Bi2S3 nanoflowers in large scale with highly oriented (001) surfaces. The synthesis route was observed to radically determine the overall morphology of the resultant product. Under hydrothermal conditions (12 h), formation of Bi2S3 flowers on nickel foil composed with the self-assembled tapered nanorods were obtained. Whereas after prolonged reaction time (24 h), formation of ultra long micro belts were observed. Interestingly, the architectured Bi2S3 flowers obtained by solvothermal route are seen to be composed with self assembled nanorods and it was also observed that the synthesis duration influences their shape, size, and areal density. Finding of such unique nanostructures on nickel foil arose by hydrothermal route exemplify a prominent photoenhanced field emission upon visible light illumination, which is attributed to the photoconductivity of Bi2S3. It is noteworthy that the field emission studies reveal low turn-on field of ∼1.04 V/μm, required to draw an emission current density of ∼0.1 μA/cm2, which is found to be lower than the earlier reports. The average emission current is observed to be stable over the duration of 3 h. In addition, field emission behavior of a single Bi2S3 flower (pasted on a tungsten microtip) has also been investigated. The high sensitivity and fast response of photoenhanced emission current switching indicate the Bi2S3 nanoflowers as a promising candidate for micro/nano-optoelectronic devices.Graphical abstract.