Abstract of the Thesis ……………………………………………… i Acknowledgement ……………………………………………… iv Table of contents ……………………………………………… vi List of Figures ……………………………………………… viii List of Schemes ……………………………………………… xii CHAPTER 1 Methods for the Fabrication of Ordered Nanostructure Assembly and Their Applications 1.1 Introduction 1 1.1.2 Methods for Fabricating Assembly of Nanocrystals 3 1.2.1 Langmuir−Blodgett (LB) Technique 3 1.2.2 Evaporation-Based Technique 6 1.2.3 Electrostatic Interaction 12 1.2.4 Solvophobic Interaction 14 1.3 Properties and Applications 16 1.4 References 22 CHAPTER 2 Fabrication of Long-Range Ordered Nanocrystal Assembly and Supercrystals on Substrates Using Gold Nanocubes, Octahedra and Rhombic Dodecahedra as Building Blocks 2.1 Introduction 25 2.2 Experimental Section 27 2.2.1 Chemicals 27 2.2.2 Synthesis of Gold Seeds 27 2.2.3 Synthesis of Cubic Nanocrystals (40 nm) 27 2.2.4 Synthesis of Rhombic Dodecahedral Gold Nanocrystals (40 nm) 28 2.2.5 Synthesis of Larger Cubic and Rhombic Dodecahedral Gold Nanocrystals 28 2.2.6 Synthesis of Octhedral Gold Nanocrystals 29 2.2.7 Long-Range Ordered Self-Assembly of Gold Nanocubes 30 2.2.8 Instrumentation 33 2.3 Results and Discussion 34 2.4 Conclusion 68 2.5 References 69 LIST OF FIGURES CHAPTER 1 Methods for the Fabrication of Ordered Nanostructure Assembly and Their Applications Figure 1.1 The setup of LB technique and SEM images of superlattices composed of truncated cubes, cuboctahedra and octahedra of silver nanocrystals. 5 Figure 1.2 The mechanism of Au nanocrystal self-assembly during the drying process. 8 Figure 1.3 Schematic illustration of a Au nanorod and SEM images of ordered Au nanorod superstructures. 9 Figure 1.4 SEM images of the ordered assembly formed from polyhedra, nanocubes, and bipyramids. 10 Figure 1.5 FE-SEM images of four different alkyl chain length thiolate- stabilized Au nanoparticle superlattices and their diffraction patterns. 11 Figure 1.6 Scheme of AuMUA and AgTMA nanoparticles and SEM images of AuMUA-AgTMA crystals. 13 Figure 1.7 The crystallization progress and SEM images of octahedral MnO nanocrystals formed cubic supercrystals. 15 Figure 1.8 Snapshots of cuboctahedral nanocrystals superlattice and corresponding SEM images at surface pressures of = 0 , 1.0 and 14 mN m–1. 19 Figure 1.9 Reflectance spectra of cubes, cuboctahedra, and octahedra superlattice, and Dark-field scattering spectra for the cuboctahedra monolayer. 20 Figure 1.10 Extinction spectra of four different chain length thiolate- stabilized Au nanoparticle superlattices and isolated Au nanoparticles. 21 Figure 1.11 I-V curves of silver nanoparticle deposited on Au(111) substrate. 21 CHAPTER 2 Fabrication of Long-Range Ordered Nanocrystal Assembly and Supercrystals on Substrates Using Gold Nanocubes, Octahedra and Rhombic Dodecahedra as Building Blocks Figure 2.1 The setup for assembling nanocrystals and OM image of the ordered gold nanocube assembly on a substrate. 32 Figure 2.2 Optical microscopy images for gold nanocube assembly after drying. 35 Figure 2.3 SEM images of assembled structures from gold nanocubes with different surfactant concentrations or drying times. 39 Figure 2.4 SEM image of gold cubic supercrystals at 90 °C. 42 Figure 2.5 SEM images and schematic drawings of two types of gold nanocube assembly. 43 Figure 2.6 SEM images of long-range ordered assembled structures from octahedral gold nanocrystals. 49 Figure 2.7 SEM images and schematic drawings of the three types of self-assembled structures of the octahedral gold nanocrystals. 50 Figure 2.8 SEM images and schematic drawings of octahedral gold supercrystals. 53 Figure 2.9 SEM images and schematic drawings of platelike gold supercrystals. 54 Figure 2.10 SEM images of rhombic dodecahedral gold supercrystals. 55 Figure 2.11 SEM images of rhombic dodecahedral and octahedral gold assembled structures at room temperature in a drying oven. 57 Figure 2.12 SEM images of assembled structures from larger gold nanocubes nanocrystals. 60 Figure 2.13 SEM images of assembled structures from larger rhombic dodecahedral gold nanocrystals. 61 Figure 2.14 SEM images of 2D monolayer assembly from larger octahedral gold nanocrystals. 62 Figure 2.15 SERS spectra of four different assembled structures and corresponding SEM images. 65 Figure 2.16 UV-vis spectra of ordered gold nanocube assembly and corresponding SEM images. 67 LIST OF SCHEMES CHAPTER 2 Fabrication of Long-Range Ordered Nanocrystal Assembly and Supercrystals on Substrates Using Gold Nanocubes, Octahedra and Rhombic Dodecahedra as Building Blocks Scheme 2.1 Schematic illustration of the synthesis procedure for preparing Au nanocrystals with different sizes and shapes. 30 Scheme 2.2 Schematic illustration of the procedure for preparing Au colloidal solution containing different CTAC concentrations. 32 Scheme 2.3 The mechanism of gold nanocrystal self-assembly during the slow drying process at high surfactant concentration. 36 Scheme 2.4 Schematic illustration of ordered gold nanoparticle assembly by entropy-driven formation. 42