Zno tio2 coreshell part 2
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The document provides an overview of an independent study on synthesizing ZnO-TiO2 core-shell nanostructures using a hydrothermal method. The study was conducted by Hoàng Văn Tiến, a student at Ha Noi University of Science and Technology. The outline includes why the topic was chosen, background on ZnO-TiO2, the hydrothermal synthesis process, analysis methods used, results and discussions, and a summary. The student aims to develop new efficient photocatalysts for degrading organic pollutants using sunlight by growing ZnO nanorod arrays and depositing TiO2 shells via a hydrothermal coating process. Characterization techniques such as XRD and SEM will be used to analyze the
Zno tio2 coreshell part 2
- 1. HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY **** ADVANCED TRAINING PROGRAM **** OVERVIEWS OF INDEPENDENT STUDY: SYNTHESIS OF ZnO-TiO2 CORESHELL NANOSTRUCTURES BY HYDROTHERMAL METHOD Name : Hoàng Văn Tiến Class : MSE-K54 ID Student : 20092697 Instructor : Dr. Nguyễn Duy Hùng-AIST
- 2. OUTLINE : • Why i choose this topic? • ZnO-TiO2 overviews • Hydrothermal methods • Process of researching • Analysis method • Results and discussions • Summary
- 3. WHY I CHOOSE THIS TOPIC ? Types of solar cell : - Buried contact solar cell • Cadmium telluride solar cell • Copper indium gallium selenide solar cells • Dye-sensitized solar cell • Gallium arsenide germanium solar cell • Hybrid solar cell • - Organic solar cell - Nanocrystal solar cell - Plasmonic solar cell - Plastic solar cell - Polycrystalline solar cell - Polymer solar cell - Quantum dot solar cell - Solid-state solar cell - Thin film solar cell - Monocrystalline solar cell - Multijunction solar cell - ……………………….
- 4. WHY I CHOOSE THIS TOPIC ? • Harmful organic compounds in the ecological unit are the main concern for the scientific society, which is causative agent of water pollution and severe contamination of the environment. Waste-water containing organic dyes (organicpollutants) inhibit sunlight penetration which suppressesphotosynthetic reaction. • Metal oxide semi-conducting nano materials have been proven to be very efficient photocatalysts for the degradation of organic dye pollutants with the help of solar light. In particular, TiO2 and ZnO are the most versatile semiconductor oxides with applications across a wide range from cosmetics to air purification. • However, the poor consumption of solar energy and the short diffusion length of photogenerated exciton are the two key factors restrictive to further improvement of photocatalytic efficiency develop new and efficient sunlight-sensitive photocatalysts. •
- 5. FTO :Fluorine doped Tin Oxide
- 7. TiO2 (rutile ) - Pure titanium dioxide is colorless in the massive state, non-toxic, thermally stable, inert versus acids, alkalis and solvents, and insoluble. - Rutile is the most stable and the most abundant form - Nanocrystalline TiO2 usually exhibits a wider band gap than that of the bulk (3.03 eV for rutile and 3.20 eV for anatise) Refractive index Lattice Constants, Е n=2.54 for anatise or 2.75 for rutile at λ = 550 nm) a = 4.593 c = 2.958 Brookite-orthorhombic Anatise-tetragonal
- 10. HYDROTHERMAL METHODS • The term “hydrothermal” usually refers to any heterogeneous reaction in the presence of aqueous solvents or mineralizers under high pressure and temperature conditions to dissolve and recrystallize materials that are relatively insoluble under ordinary conditions. • Uses : A large number of compounds belonging to practically all classes have been synthesized under hydrothermal conditions: elements, simple and complex oxides , tungstates , molybdates , carbonates, silicates , germanates etc. Hydrothermal synthesis is commonly used to grow synthetic quartz , gems and other single crystals with commercial value.
- 12. EXPERIMENTALPROCEDURE • Growth of ZnO nanorods array • Deposition of TiO 2 shells on ZnO nanorods • Materials characterization • X‐ray diffraction (XRD) used to phase characterization and crystalline size, • Scanning electron microscopy (SEM) to morphology and microstructure investigations. • Diffusive UV‐visible‐NIR spectrometry to band gap calculations • Solar cell fabrication and testing
- 13. GROWTH OF ZNO NANORODS ARRAY • Process : - Substrate preparation - Growth ZnO nanorod • Prepare : -Zn(COOCH3)2.2H2O - Zn(NO3)2 .6H2O - DI water -Dimethylformamide (DMF): (CH3)2NC(O)H -hexamethylenetetramine C6H12N4 -FTO substrate -Powder coating gun
- 14. SUBSTRATE PREPARATION • Clean substrate • 0.44g Zn(COOCH3)2.2H2O + 20ml DMF • Dry substrate to150 oC • Coating • Drying
- 15. GROWTH ZNO NANOROD • 2 (Zn(NO3)2 .6H2O) :1 HTMA - 0.75 g Zn(NO 3)2 .6H2O +150ml DI • 0.35 g hexamethylenetetramine +100ml D • 1 (Zn(NO3)2 .6H2O) :1 HTMA - 0.45 g Zn(NO 3)2 .6H2O +150ml DI • 0.42 g hexamethylenetetramine +100ml D • 2 (Zn(NO3)2 .6H2O) :1 HTMA - 0.75 g Zn(NO 3)2 .6H2O +150ml DI • 0.35 g hexamethylenetetramine +100ml DI
Editor's Notes
- #2: Guidance : sựhướngdẫn
- #6: Overall peak power conversion efficiency for current DSSCs is about 11%Current record for prototypes lies at 15%Dresden, Germany, January 16, 2013 – Heliatek GmbH, the leader in organic solar films, today announced a record breaking 12.0% cell efficiency for its organic solar cells. This world record, established in cooperation with the University of Ulm and TU Dresden, was measured by the accredited testing facility SGS. The measurement campaign at SGS also validated the superior low light and high temperature performances of organic photovoltaics (OPV) compared to traditional solar technologies.
- #7: Wurtzite :Hexagonal structures, same as CdSe, GaN…..
- #8: refractive index (n=2.54 for anataseor 2.75 for rutile at = 550 nm)