Effect of Capping Agent Concentration on Photophysical Properties of Zinc Sulfide Nanocrystals

Abstract

Zinc Sulfide (ZnS) nanoparticles with varying concentration of capping agent were prepared using chemical technique. These particles were characterized using scanning electron microscope (SEM), atomic force microscope (AFM) and x-ray diffraction (XRD). It is observed that particle size decreases with increasing capping agent concentration. Optical absorption studies show that the absorption edge shifts towards blue region as the capping agent concentration is increased indicating that effective band gap energy increases with decreasing the particle size. Using the effective mass approximation model the particle size of nanoparticles has been estimated from the increased band gap, which is practically the same as obtained by XRD. Photoluminescence (PL) investigations show that ZnS samples give single peak with stoke shift. PL emission peak is obtained at 460 nm for uncapped nanoparticles. The PL spectra of ZnS nanoparticles with different capping agent concentration reveals that the emission becomes more intensive and shifts towards blue as the size of the particles is reduced.

Laser assisted solid state reaction for the synthesis of ZnS and CdS nanoparticles from metal xanthate

“…Subsequently, the emitted photon has comparatively lower energy giving photoluminescence peak at higher wavelength. Chen et al [41] has also reported PL peak of ZnS in this range, while Tamrakar et al [42] obtained the PL peak at 460 nm for uncapped ZnS nanoparticles, which then shifted up to 370 nm as capping concentration increased.…”

Synthesis, characterization and photoluminescence studies of Mn doped ZnS nanoparticles

“…There are several methods to synthesize ZnS nanoparticles with various Mn 2+ concentrations such as sol-gel, chemical vapour deposition, and chemical co-precipitation method hydrothermal method [49][50][51][52]. So among the different synthesis processes, chemical co-precipitation method is used because of its manifold advantages like simple, easy handling, economical and capability for large scale production.…”

A facile approach called nebulized spray pyrolysis to deposit MnS thin films: Effect of solution concentration with EDTA on the physical properties

“…Optical excitation of electrons across the band gap is strongly allowed, producing an abrupt increase in absorption at the wavelength corresponding to the band gap energy. This feature in the optical absorption spectrum is known as the optical absorption edge [21]. It may be mentioned that the optical absorption spectra recorded in the visible and near infrared (NIR) regions are related to the electronic transitions, which are useful in understanding the electronic band structure of the deposited films [22].…”