| Titre : | Elaboration of pure and Bi-doped ZnO nano-powders with the sol-gel method |
| Auteurs : | Nezzal Hala, Auteur ; Redjouh Nour El Houda, Auteur ; Louiza Arab , Directeur de thèse |
| Type de document : | Monographie imprimée |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2022 |
| Format : | 1 vol. (61 p.) |
| Langues: | Français |
| Mots-clés: | zinc oxide, Bismuth, nanopowder, sol-gel, XRD, UV–vis, FTIR |
| Résumé : |
In this work, undoped and Bi-doped ZnO nanopowders with different dopant
concentrations (3%, 6% and, 8%) have been successfully synthesized with a soft chemistry method: the sol-gel route. This method produces samples with high purity, homogeneity, and a structure of easy control. The powders have been characterized using the following techniques: X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), and Fourier transform infrared (FTIR) spectroscopy. The XRD results confirm that all the samples exhibit a polycrystalline hexagonal wurtzite structure of the ZnO. The crystallite size was found to vary between 28.1 and 57.4 nm. The results of UV analysis showed a decrease in the values of the band gap energy (Eg) and the Urbach energy with the increase of the Bi doping concentration. In addition, Fourier transforms infrared (FTIR) spectroscopy showed the presence of a zinc oxide-specific bond in the samples. The simple synthesis method proposed represents an interesting approach to produce Bi-doped ZnO nanopowders, with promising potential for different applications. |
| Sommaire : |
Acknowledgements:...........................II
Dedication:……………………………………….………………………………………….III List of figures:……………………………………………………………………………….XI List of tables:………………………………………………………………………………XIII GENERAL INTRODUCTION:……………………………………………………………...1 Chapter one: Bibliographic studies I.1.Introduction:………………………………………………………………………………..3 I.2.History of Zinc oxide (ZnO) research:……………………………………………………..3 I.3.Properties of zinc oxide:……………………………………………………………………4 I.3.1.Physical Properties:…………………………………………………………………..4 I.3.1.1.Crystal structure:………………………………………………………….5 I.3.1.2.Electronic band structure:…………………………………………………7 I.3.1.3.Electrical Properties:………………………………………………………8 I.3.1.4.Optical Properties:………………………………………………………...9 I.3.1.5.Mechanical Properties:…………………………………………………..10 I.3.1.6.Piezoelectric effect:……………………………………………………...10 I.3.2.Chemical Properties:………………………………………………………………11 I.4.Applications of zinc oxide:………………………………………………………………..12 I.4.1.Rubber manufacture:……………………………………………………………….12 I.4.2.Medical uses:……………………………………………………………………….12 I.4.3.Food additives:……………………………………………………………………..13 I.4.4.Anti-corrosive coatings:…………………………………………………………….13 I.4.5.Electronic applications:…………………………………………………………….13 I.4.6.Varistors:…………………………………………………………………………..14 I.5. Properties of zinc oxide Nanostructures:………………………………………………..14 I.5.1.Morphology Controlled:…………………………………………………………..14 VIII I.5.2.Physico-chemical Properties:……………………………………………………...15 I.5.2.1.Nanobelts:……………………….……………………………………….15 I.5.2.2.Nanowires:……………………….……………………………………….16 I.5.2.3.Nanorods:………………………..………………………………………..16 I.6.Advantages of zinc oxide:………..……………………………………………………….16 REFERENCES:…………………………………………………………………………….17 Chapter two: Methods and materials II.1.Introduction:……………………………………………………………………………...19 II.2.Synthesis of Inorganic Nanomaterials:…………………………………………………...19 II.3.Sol-Gel process:………………………………………………………………………….20 II.3.1.Introduction:……………………………………………………………………….20 II.3.2.An overview of sol-gel process steps:…………………………………………….20 II.3.2.1.Hydrolysis and condensation:……………………………………………20 Hydrolysis reaction:…………………………………………………...20 Condensation reaction:………………………………………………..20 II.3.2.2.Gelation:…………………………………………………………………21 II.3.2.3.Ageing:…………………………………………………………………..21 II.3.2.4.Drying:…………………………………………………………………...21 II.3.2.5.Densification:……………………………………………………………22 II.3.3.Major control parameters of sol-gel process:……………………………………...22 II.3.3.1.Chemical compositions of the precursors:………………………………23 II.3.3.2.Hydrolysis ratio:…………………………………………………………23 II.3.3.3.Catalysts:………………………………………………………………...24 II.3.3.4.pH value:………………………………………………………………...24 II.3.3.5.Reaction temperature:……………………………………………………24 IX II.3.4.Advantages and shortages of sol-gel processing:………………………………….24 II.3.5.Applications of Sol Gel method:…………………………………………………26 II.4.Synthesis of pure and Bi doped zinc oxide powER….27 II.4.1.Experimental conditions:……….27 II.4.2.Experimental details:…………28 II.4.2.1.Pure ZnO nano-powders:…….28 II.4.2.2.Bi-doped ZnO nano-powders:…….28 II.4.3.Calcination treatment:…………..30 II.5. ZnO powder characterization techniques:…….32 II.5.1.Structural characterization:…………...32 II.5.1.1.X-ray diffraction (XRD):…….32 II.5.1.2.Determination of the grains size:….33 II.5.1.3.Determination of the interreticular distances and the cell parameters:……34 II.5.1.4. Determination of the lattice strain and the dislocation density:…………..34 II.5.1.5. Determination of texturing coefficients:……….35 II.5.2.Optical characterization:…………...35 II.5.2.1.The Optical Gap:……………..36 II.5.2.2.The Absorption Coefficient:………37 II.5.2.3.Urbach energy:…………….38 II.5.2.4. Sample preparation:…………………39 II.5.3.Chemical characterization:…………………….39 II.5.3.1.Fourier Transform Infrared Spectroscopy (FTIR):…….39 II.5.3.2.Sample preparation:………….40 REFERENCES:…………..41 X Chapter three: Results and discussions III.1. Introduction:………………….43 III.2. Results and discussions:……………43 III.2.1. Structural study:…………………….43 III.2.1.1.Crystallite size, lattice strain and dislocation density variation:…………47 III.2.1.2.Lattice parameters:………………….50 III.2.1.3.The texture coefficient:……………..52 III.2.2.Optical study:…………………….53 III.2.2.1.Band gap energy:……………………54 III.2.2.2.Urbach energy:………………….55 III.2.3.Chemical study:……………………57 REFERENCES:……………………….59 GENERAL CONCLUSION:…………………….61 |
Disponibilité (1)
| Cote | Support | Localisation | Statut |
|---|---|---|---|
| MPHY/594 | Mémoire master | bibliothèque sciences exactes | Empruntable |
