TABLE OF CONTENTS Title Page i Table of Contents ii List of Figures v List of Tables ix Abstract of The Thesis x CHAPTER 1 A SURVEY ON GOLD NANOPARTICLES 1.1 Introduction 1 1.2 Applications of Size- and Shape-Controlled Gold Nanoparticles 5 1.2.1 Zero-Dimensional Au Nanoparticles as Colorimetric Sensors 5 1.2.2 One-Dimensional Au Nanorod Linkage as Cysteine and Glutathione Selective Detectors 8 1.3 Synthesis of Metal Nanoparticles with Size and Shape Control 11 1.3.1 Seed-Mediated Growth Method 11 1.3.2 Polyol Process Using PVP 14 1.3.3 Photochemical Process for the Synthesis of Anisotropic Nanostructures 19 1.4 Investigation of 2-D Nanoparticles 21 1.5 References 24 CHAPTER 2 A THERMAL AQUEOUS SOLUTION APPROACH FOR THE SYNTHESIS OF TRIANGULAR AND HEXAGONAL GOLD NANOPLATES WITH THREE DIFFERENT SIZE RANGES 2.1 Introduction 26 2.2 Experimental Section 28 2.3 Results and Discussion 32 2.4 Conclusion 47 2.5 References 49 CHAPTER 3 AN IMPROVED HIGH-YIELD SYNTHESIS OF GOLD NANOPRISMS 3.1 Introduction 52 3.2 Experimental Section 53 3.3 Results and Discussion 54 3.4 Conclusion 62 3.5 References 63 LIST OF FIGURES CHAPTER 1 A SURVEY ON GOLD NANOPARTICLES Figure 1.1 Size effects on the surface plasmon absorption of spherical gold nanoparticles between 9 and 99 nm. 3 Figure 1.2 TEM image of gold nanorods with an average aspect ratio of 4.1, and the corresponding UV–vis absorption spectrum of the colloidal gold nanorod solution. 4 Figure 1.3 Schematic Representation of the K+-Induced Aggregation via Sandwich Complexation of Crown-Thiol Molecule 1 in a Sodium-Containing Solution. 7 Figure 1.4 Absorption spectral changes of Au nanorods in acetonitrile/water on addition of cysteine or glutathione. 3D plot showing the selectivity of cysteine (3 □M), glutathione (12 □M), and other R-amino acids (10 □M). 10 Figure 1.5 Schematics showing seed-mediated growth for synthesis of gold and silver nanorods. 13 Figure 1.6 Low- and high-magnification SEM images of slightly truncated silver nanocubes synthesized with the polyol process. 16 Figure 1.7 SEM images of silver nanocubes after they had reacted with 0.3 mL and 1.5 mL of aqueous HAuCl4 solution (1 mM). 18 Figure 1.8 Time-dependent UV–vis spectra and Scheme 1 showing photoinduced conversion of silver nanospheres to nanoprisms (excitation at 670nm). 20 Figure 1.9 Low magnification (a) and high magnification (b) SEM images of the precipitate. The inset shows that the thickness of a single nanoplate is about 47.7 nm. 22 CHAPTER 2 A THERMAL AQUEOUS SOLUTION APPROACH FOR THE SYNTHESIS OF TRIANGULAR AND HEXAGONAL GOLD NANOPLATES WITH THREE DIFFERENT SIZE RANGES Figure 2.1 Structures of sodium citrate and cetyltrimethylammonium bromide. 31 Figure 2.2 SEM image of the micron-sized gold plates. Inset shows a SEM image of the side view of two overlapping plates. Optical image of the micron-sized plates showing their golden color. 34 Figure 2.3 Size distribution histograms of the gold nanoplates. 36 Figure 2.4 Powder XRD pattern of the micron-sized gold nanoplates. Inset shows the enlarged powder XRD pattern in the (200) peak region. 37 Figure 2.5 TEM image of medium-sized gold nanoplates. TEM images of gold nanoplates arranged into chain-like structures. 40 Figure 2.6 TEM images of small-sized gold nanoplates. Plate thickness can be estimated from the inset of with slightly larger nanoplates. 41 Figure 2.7 UV–vis absorption spectra for the three different-sized gold nanoplates. 42 CHAPTER 3 AN IMPROVED HIGH-YIELD SYNTHESIS OF GOLD NANOPRISMS Figure 3.1 Absorption spectra of gold nannoprisms formed after reaction at 100 °C for 0, 20, and 40 min. 56 Figure 3.2 UV–vis absorption spectrum of the HCl-treated Au nanotriangle solution after 20 minutes of reaction at 100 °C and TEM images of the resulting nanoprisms. 59 Figure 3.3 UV–vis absorption spectrum of the HCl-treated Au nanotriangle solution after 40 minutes of reaction at 100 °C and the TEM images of the nanoprisms. 61 LIST OF TABLES CHAPTER 1 A SURVEY ON GOLD NANOPARTICLES Table 1 Different approaches for the synthesis of gold nanoplates 23