| Titre : | Elaboration of pure and doped ZnO powders with the sol gel method |
| Auteurs : | Aya Latif, Auteur ; Louiza Arab , Directeur de thèse |
| Type de document : | Thése doctorat |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2024 |
| Format : | 1 vol. (130 p.) / ill., couv. ill. en coul / 30 cm |
| Langues: | Anglais |
| Mots-clés: | ZnO, Sol-Gel, Nanopowder, Bi: ZnO, Ga: ZnO, Antibacterial activity, I-V characteristics |
| Résumé : |
Undoped, doped, and co-doped zinc oxide powders with different concentrations of bismuth and gallium were prepared by the chemical sol-gel method using zinc acetate, citric acid, bismuth nitrate, and gallium nitrate as precursors and ethylene glycol as a solvent. The effect of doping on zinc oxide powders' structural, morphological, and optical properties was studied. The powders were characterized using various techniques such as X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy, and Fourier Transform Infrared spectroscopy. the results obtained using the X-ray diffraction technique showed that all the prepared powders have a hexagonal crystalline structure with good crystallinity and nanocrystalline size. A blue shift was observed in the UV-visible spectra of gallium-doped zinc oxide powders compared to those doped with bismuth and co-doped with bismuth and gallium. In addition, the results of UV-visible spectroscopy showed that doping zinc oxide powders with gallium led to a significant increase in the band gap energy while doping with bismuth and co-doping with bismuth and gallium showed a decrease in the band gap energy. Infrared spectral analysis showed a specific association with zinc oxide in all samples. The antibacterial activity of the prepared powders was tested against different types of bacteria. The results showed that pure, doped, and co-doped zinc oxide nanoparticles exhibited strong antibacterial activity against a wide range of bacteria, including Gram-negative Escherichia coli, Klebsiella pneumoniae, and Enterobacter aerogenes, as well as Gram-positive Listeria monocytogenes. These findings demonstrate the remarkable effectiveness of zinc oxide in inhibiting bacterial growth. The prepared samples were subjected to voltage-current testing, and the results showed that the type of doping has a significant impact on the electrical behavior of variable zinc oxide resistance. Doping zinc oxide with bismuth led to aremarkable increase in breakdown voltage, indicating an improvement in resistor lifetime. While doping with gallium led to an increase in current leakage. Dual doping of zinc oxide with bismuth and gallium showed promising results, providing a balance between high breakdown voltage and severe current leakage. |
| Sommaire : |
DEDICATION ………………………………………………………………………………...i ACKNOWLEDGEMENT……………………………………..………………………………ii ABSTRACT………………………………………………………………………………….ivالملخص RESUME………………………………………………………………………………………v CONTENT TABLE……………………………………………………………………………vi LIST OF FIGURES……………………………………………………………………………xi LISTE OF TABLES………………………………………………………………………….xvi General Introduction……………………………………………………………………………1 Refrenses……………………………………………………………………………………….3 Chapter I: overview of zinc oxide I.1. Introduction………………………………………………………………………………...4 I.2. General properties of ZnO………………………………………………………………….5 I.2.1. Crystallographic properties……...……………………………………………..……5 I.2.2. Electric properties…………………….………………………..……………..……10 I.2.3. Piezoelectric properties………………….….………………………………..…….12 I. 2.4. Optical properties………………………..………………………………..……….12 I.2.4.a. Optical absorption…………………..……………………………………….13 I.2.4.b. Photoluminescence…….……………………………………………………13 I.2.5. Chemical and catalytic properties………….……………………………………….14 I.2.6. The antibacterial properties……….………………………………………………..15 I.3. Defects in ZnO……………………………………………………………………………16 I.4. Doping of ZnO……………………………………………………………………………16vii I.5. Different forms of ZnO……………………………………………………………………18 I.6. Application of zinc oxide………………………………………………………………….19 I.6.1. Thin films……………….………………………………………………………….19 I.6.2. Zinc oxide powder…………….……………………………………………………20 References………………...……………………………………..……………………………24 Chapter II : Materials and experimental methods II. 1. Introduction…………………………………………………………………….………..35 II. 2. Experimental methods…………………………………………………………………...35 II. 2.1. Sol-Gel…………………………………………………………………… .………...36 II. 2.2.Predominant Chemical Reactions………………………………………… .………....38 II. 2.2.a. Hydrolysis reaction……………..………..………………………………...38 II. 2.2.b. Condensation Reaction…..………..……………………………………….39 II. 2.3. The Sol-Gel Transition………………….……...………………………………....40 II. 2.4. Gelation and Gel Structure……….…………..…………………………………..41 II. 2.5. Heat Treatment…….……...……………………………………………………....41 II. 2.5.a Gel Drying…….…………………………………………………………….42 II. 2.5.b Annealing………..…………...….………………………………………….43 II. 2.6. Advantages of the sol-gel method………………………………………………....44 II. 2.7. Drawbacks of the sol-gel method………………………………………………....44 II. 3. Preparation of ZnO powder……………………………………………………………...45 II. 3.1. Used Chemical Precursors…………………………………………………….…..45 II. 3.2. The different stages of the synthesised powder……………………………… ..…45 II. 3.3. Elaboration of doped zinc oxide nanopowder…………………………………......47 II. 4 . Characterization Method for Nanopowders……………………………………………..48viii II. 4 .1. Thermal Analysis ATG/ DSC……………………………………………………..48 II. 4 .1.a Thermogravimetric analysis (TGA)………..………………………………48 II. 4 .1.b. Differential Scanning Calorimetry (DSC)….……………………………..59 II. 4.2. X-ray Diffraction……………………………………………………...……….….51 II. 4.2. a. Apparatus……………………………………………………….……….....51 II. 4.2. b. Principle of X-ray Diffraction Measurements……………………………..52 II. 4.2. c. Determination of interatomic distances and lattice parameters……… ..…..53 II. 4.2. d. Determination of crystallite size………………...…………………………53 II. 4.3. Scanning Electron Microscope (SEM)…………………………………………....56 II. 4.3.a Apparatus………………………………..………………………………….56 II. 4.3.b. Principle of SEM…………………………………...……………………....57 II. 4.4. Ultraviolet-visible spectroscopy……………………………………...……….….59 II. 4.4.a. Apparatus……………………………………………………..……………59 II. 4.4.b. Principle of UV-visible spectrophotometer……..………………………….59 II. 4.5. Fourier transform infrared spectroscopy……….…………………………………61 References…………………………………………………………………………………….63 Chapter III: Undoped, doped, and co-doped zinc oxide properties Introduction ………………………………….………………………………………………66 Part I: Preparation and Analytical Study of Zinc Oxide Powder III. 1.1. Preparation and analytical study of prepared pur zinc oxide powder…………….…..67 III. 1.1.1. Preparation of Zinc Oxide Mixture…………………...………………………..67 III. 1.1.2. Thermal stability analysis of as-synthesized ZnO….….………………………67 III. 1. 1.3. Activation energy………………...……..…………….……………………….70 Part II: Zinc oxide doped with Bismuthix III.2.1. Structural characterization………………………...…………………………………..75 III.2.1.1. X-ray diffraction…...…………………………………………..……………….75 III.2.3.2. Fourier transformation infrared (FTIR) analysis……………………….…….…79 III.2.2. Morphological characterization………………………...……………………………..80 III.2.2.1. Scanning electronic microscopy (SEM)…………...……..……………...……..80 III.2.2.2. The compositional properties……………………………...……………………81 III.2.3. Optical characteristics…………………………………………………………………83 III.2.3.1. UV-visible absorption……………………………………… .………….…………83 Part III: Zinc oxide doped with Gallium III.3.1. Structural characterization…………………………...…………….……………..85 III.3.1.1 X-ray diffraction………………………;…………………………………...85 III.3.1.2. Fourier transformation infrared (FTIR) analysis…………………………..88 III.3.2. Morphological characterization…………………………………………………..89 III.3.2.1. Scanning electronic microscope……………………………….…………..89 III.3.2.2. The compositional properties………………………………….…………..90 III.3.3. Optical characteristics……………………………………………………………92 III.3.3.1. UV-visible absorption……………………………………….….……….....92 Part IV: Bi and Ga co-doping ZnO nanopowders III.4.1. Structural characterisation………………………………....………………………….94 III.4.1.1 X-ray diffraction………….…………………………………………….…..………94 III.4.3.2 Fourier transformation infrared (FTIR) analysis………………………………...97 III.4.2. Morphological characterization………………………………………….……………97 III.4.2.1. Scanning electronic microscope…………..……………...…………………...97 III.4.2.2. Compositional properties……..…………....……………..……………...…...98x III.4.3. Optical characteristics…………………………………………………………………99 III.4.3.1 UV-visible absorption…………...…………………………………..………….99 References……………………102 Chapter IV: Applications of the Zinc oxide elaborated IV .1. Introduction…….………………………………………………………...…...………107 Part A: Antibacterial activity IV .A.1. Antibacterial Properties of Zinc Oxide Nanoparticles………………………………108 IV .A.1.1. Preparation method…………………………….……………….…………...108 IV .A.1.2. Antibacterial activity………………………..……….………………..……..109 IV .A.1.2.1. Bi doped ZnO nanopowder …………….…………….………….……109 IV .A.1.2.2. Ga doped ZnO nanopowder…....……..……………………………….112 IV .A.1.2.3. Bi-Ga co-doped…………………………..114 Part B: Electrical behaviour IV.B.1. Electrical Properties of Zinc Oxide Nanoparticles…………………………….….…118 IV.B.1.1. Samples preparation ………….………………….…….....118 IV .4. 2.Electrical properties……………….……….…….……119 IV.B.1.2.1. Bi doped ZnO………………… ……………………..119 IV.B.1.2.2. Ga doping ZnO...………...…………...121 IV.B.1.2.3. Bi and Ga co-doped ZnO………...….…………….123 References……………………………………………..126 General Conclusion……………………………… |
Disponibilité (1)
| Cote | Support | Localisation | Statut |
|---|---|---|---|
| TPHY/140 | Théses de doctorat | bibliothèque sciences exactes | Consultable |
