Porous nanostructures of SnSe: role of ionic liquid, tuning of nanomorphology and mechanistic studies†
Abstract
In recent times, tin selenides have attracted considerable attention as an environment friendly alternative to cadmium- and lead-based optoelectronic devices. Herein, we report a one pot rapid synthesis of SnSe nanoparticles in neat imidazolium based room temperature ionic liquid (RTIL) for the first time, via electron beam irradiation. The RTIL being the host matrix provides a stabilizing environment as well as an in situ source of reducing radicals for the reduction of precursors. Additionally, it also facilitates the self-assembling of nanoparticles into porous nanomorphologies. UV-Vis absorption spectra of the nanoparticles clearly showed an excitonic peak at ∼460 nm, which indicates a strong quantum confinement. Various characterization studies i.e. XRD, XPS, Raman and EDX have confirmed the formation of SnSe. The average size of the nanoparticles as determined from the TEM measurements was found to be ∼7 nm. The FESEM measurements revealed self-assembling of globular nanoparticles into a highly porous structure. Interestingly, the variation in the dose rate was found to modify the morphology as an equivalent dose of γ-irradiation led to the transformation of porous nanostructures into corn-flake like structures. The possible mechanism behind the obtained nanomorphologies has been proposed, and was rationalized in terms of the dose rate involved and the inherent structure of the RTIL. SnSe is a highly promising emerging material of research; the utilization, integration and exploitation of such newer synthetic strategies would enable the formation as well as convenient maneuverability of its complex nanomorphologies, which might add greater dimensions to its applications.