Systematic synthesis of Bi2S3 nanoplates by template free solid-state approach and its field emission behaviour

Abstract

We have demonstrated herewith controlled synthesis of Bi2S3 nanoplates by simple, template free, one step solid-state reaction at moderate temperature. The process parameters viz. precursor ratio, reaction temperature and duration were optimized. Nanostructured Bi2S3 synthesized at optimum conditions was further characterized by XRD, FESEM and FETEM, to study their phase, morphology and structure. The microscopic and XRD study reveals the formation of nanoplates like structures of orthorhombic Bi2S3. An attempt has been made to provide with a plausible growth mechanism as a function of reaction temperature and duration. In order to exploit the high 'aspect ratio' of the Bi2S3 nanoplates and explore its feasibility as potential electron source, field emission (FE) study has been performed at base pressure of ∼1 × 10−8 mbar. The results obtained herein reveal the morphology dependent FE behaviour of Bi2S3 nanoplates. The emitter comprised of Bi2S3 nanoplates synthesized at 180 °C showed better FE properties, lower turn-on field value, delivery of large emission current density (∼1670 µA/cm2 at 6.9 V/µm) and excellent emission current stability which are comparable to alike emitters due to semiconducting nanostructures. Highly crystalline nature and high aspect ratio of Bi2S3 nanoplates might be responsible for their good FE performance. These Bi2S3 nanostructures may have potential for applications in other optoelectronics devices.