Formation of a Colloidal CdSe and ZnSe Quantum Dots via a Gamma Radiolytic Technique

Aeshah Salem,Nayereh Soltani,Shahidan Radiman,Elias Saion,Abdul Shaari,Halimah Kamari,Naif Al-Hada

doi:10.3390/app6100278

Abstract

Colloidal cadmium selenide (CdSe) and zinc selenide (ZnSe) quantum dots with a hexagonal structure were synthesized by irradiating an aqueous solution containing metal precursors, poly (vinyl pyrrolidone), isopropyl alcohol, and organic solvents with 1.25-MeV gamma rays at a dose of 120 kGy. The radiolytic processes occurring in water result in the nucleation of particles, which leads to the growth of the quantum dots. The physical properties of the CdSe and ZnSe nanoparticles were measured by various characterization techniques. X-ray diffraction (XRD) was used to confirm the nanocrystalline structure, energy-dispersive X-ray spectroscopy (EDX) was used to estimate the material composition of the samples, transmission electron microscopy (TEM) was used to determine the morphologies and average particle size distribution, and UV-visible spectroscopy was used to measure the optical absorption spectra, from which the band gap of the CdSe and ZnSe nanoparticles could be deduced.

Highlights

Over the past two decades, semiconductor nanoparticles or quantum dots with sizes between1 and 20 nm, have received much attention because of the quantum confinement effect of their surface electrons
In light of the above results, this report is aimed at creating colloidal cadmium selenide (CdSe) and zinc selenide (ZnSe) quantum dots via a gamma radiolytic technique
A single-step radiolytic technique based on 60 Co gamma irradiation was applied in the preparation of CdSe and ZnSe nanoparticles

Summary

Introduction

1 and 20 nm, have received much attention because of the quantum confinement effect of their surface electrons. In this dimension, the particles are in the transition between the bulk and molecular regimes and contain hundreds to a few thousand atoms only. The electronic, optical, and magnetic properties of quantum dots can be tailored by changing the material composition and varying the physical size [1,2,3]. The method of synthesis and, to some extent, the local environment can influence the particle size and physical properties of quantum dots. Some of the techniques associated with the synthesis of colloidal CdSe and ZnSe quantum dots are chemical synthesis [12,13], photochemical

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