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 : Hong Vn Tin Class : MSE-K54 ID Student : 20092697 Instructor : Dr. Nguyn Duy Hng-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 scientic 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 efcient 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 purication. 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 efciencydevelop new and efcient sunlight-sensitive photocatalysts. 5. FTO :Fluorine doped Tin Oxide 6. 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, n=2.54 for anatise or 2.75 for rutile at = 550 nm) a = 4.593 c = 2.958Brookite-orthorhombicAnatise-tetragonal 7. 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. 8. EXPERIMENTALPROCEDURE Growth of ZnO nanorods array Deposition of TiO 2 shells on ZnO nanorods Materials characterization Xray diffraction (XRD) used to phase characterization and crystalline size, Scanning electron microscopy (SEM) to morphology and microstructure investigations. Diffusive UVvisibleNIR spectrometry to band gap calculations Solar cell fabrication and testing 9. 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 10. SUBSTRATE PREPARATION Clean substrate 0.44g Zn(COOCH3)2.2H2O + 20ml DMF Dry substrate to150 oC Coating Drying 11. GROWTH ZNO NANOROD - temperatures : 80 0C - Times : 1h -2h-3h - Concentrations : 2 (Zn(NO3)2 .6H2O) :1 HTMA- 0.75 g Zn(NO 3)2 .6H2O +150ml DI 0.35 g hexamethylenetetramine +100ml D1 (Zn(NO3)2 .6H2O) :1 HTMA- 0.45 g Zn(NO 3)2 .6H2O +150ml DI 0.42 g hexamethylenetetramine +100ml D2 (Zn(NO3)2 .6H2O) :1 HTMA- 0.75 g Zn(NO 3)2 .6H2O +150ml DI 0.35 g hexamethylenetetramine +100ml DI 12. t < 1 0C Heat controllers 13. PHOTOLUMINESCENCE381 nm 14. SEM ANALYSIS 15. DEPOSITION OF TIO 2 SHELLS ON ZNO NANORODS Preparations : ZnO nanorods on FTO substrate