The uniqueness of size dependent functional properties of II-VI semiconductor nanocrystals have led to the development of various techniques for determination of shape, size and distributions, although the accurate measurements of the particle sizes has always been a fundamental task in nanoscience and even become more crucial with the discovery of quantum confinement effect. A comparison of the well established techniques X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and small angle neutron scattering (SANS) with an emphasis on size and distribution of the prepared samples are reported in order to elaborate more precise techniques for the analysis of particles sizes. Modified Scherrer formula for spherical particles has been used to calculate the particle sizes from XRD spectra. Analysis of SAXS data has been reported using Guinier model. Small angle neutron scattering measurements has been performed for ZnO nanocrystals and the scattering data obtained is simulated for polydisperse sphere. The bare ZnO, ZnS and CdS and doped with Mn2+ systems are taken within the framework of our discussion. These materials were synthesized by chemical precipitation route and found to have size distribution from 2 to 6 nm for spherical particles. Sizes determined from various techniques are in good agreement with each other however small angle scattering technique is more reliable than XRD to determine the sizes of the nanoparticles.
In the current age, electric‐driven products based on large‐scale stationary energy‐storage devices, sodium‐ion batteries (SIBs) are good promising candidates due to their comparable low cost, environment friendliness, high efficiency, and relatable huge abundance. An anode plays a vital role in the high performance of rechargeable batteries, so it becomes necessary to focus on the research on high‐performance anode materials. Recently, a number of researchers developed advanced host materials for SIBs to boost their energy density, cycle efficiency, and safety measures. In recent years, nanostructured metal sulfides like MoS2, SnS2, and WS2 with their novel structure‐based anode materials are the focus of the key research in sodium‐storage applications because of their comparable high conductivity, high capacity, good cycle life, and unmatched chemical and physical properties. In addition, these metal sulfides exhibit high mechanical, thermal, and structural stability, which supports them to find their place as an anode material for high‐performance SIBs in large‐scale energy storage production. Herein, the selected metal sulfide‐based nanostructures synthesized by chemical routes are extensively reviewed and their electrochemical properties for application as a high‐performance anode material in the SIBs are explored.
We synthesized the ZnS:Mn2+ nanoparticles passivated by biocompatible layer, namely, biotin by chemical precipitation route and studied their temporal evolution for size, structure, optical, and photoluminescence stability. To monitor the structural and optoelectronic properties of the nanoparticles with time, we have characterized the grown product by x-ray diffraction, small angle x-ray scattering, UV visible, and photoluminescence spectroscopic techniques at a regular interval for a period of three months. Results showed that the properties of nanophosphors capped with biotin are remaining the same even after 3 months. Energy dispersive x-ray analysis of 3 month aged sample shows long time compatibility between ZnS:Mn2+ nanoparticles and the biotin. This is also confirmed by electron microscopy that the growth of the nanoparticles is strongly arrested by the biotin. X-ray photoelectron spectra were also recorded to show the chemical state of the elements. Enhanced ratio of Zn 2p to Mn 2p peaks in the x-ray photoelectron spectra of ZnS:Mn2+ nanoparticles shows that the Mn2+ ions are incorporated within ZnS host matrix. We found that biotin capping will enhance the luminescence from ZnS:Mn2+ nanoparticles as compared to without capped particles. Absence of biotin will gradually degrade the luminescence upon aging while drastic degradation in luminescence intensity was observed after annealing. Properties show that biotin also protected the nanoparticles from any environmental attack.
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