張煥宗臺灣大學：化學研究所楊儒興Yang, ZusingZusingYang2007-11-262018-07-102007-11-262018-07-102007http://ntur.lib.ntu.edu.tw//handle/246246/51919中文摘要 奈米材料擁有特殊的光學、電性、磁性等特殊性質，以致於在近年來被廣泛地應用於光電材料、磁性材料以及生物感測器等。本論文主要描述幾種奈米材料的合成，所合成的奈米材料包括金-銀奈米棒、金-銀-汞奈米棒、花狀金奈米材料、花狀銀奈米材料、金-鐵複合奈米材料，以及方塊狀氧化亞銅奈米粒子。其中，金-銀奈米棒與金-銀-汞奈米棒的合成方法主要是在鹼性條件下，利用維他命C(ascorbic acid)還原金、銀和汞離子成金、銀和汞原子後並沈積於金奈米棒表面上，以形成金-銀奈米棒與金-銀-汞奈米棒。濕式化學合成法則可以有效地在水溶液下合成出花狀金(銀)奈米材料，首先，金(銀)原子會沈積於金(銀)奈米粒子表面上，而產生花瓣狀奈米粒子。隨著金(銀)原子繼續地沈積，花狀金(銀)奈米材料就可以成功地產生。同樣地，在有鐵奈米粒子存在下，利用上述相似的方法，亦可以成功地合成出金-鐵複合奈米材料。方塊狀氧化亞銅奈米粒子之合成則是在鹼性環境下，利用維他命C(ascorbic acid)將硝酸銅還原成氧化亞銅奈米粒子並以果糖作為保護劑而得之。 長寬比(aspect ratio)為1.90-4.10之金-銀奈米棒和2.89-4.10的金-銀-汞奈米棒在紫外可見光區擁有相當高的吸收係數(extinction coefficients；5.02 × 109 ~ 4.73 × 1010 M-1cm-1)；花狀金(銀)奈米材料在紫外可見光與近紅外光區則有很強的吸收以及高導電性(1.97Abstract Nanomaterials hold great potential to be photovoltaic, electronic, magnetic, and biosensing materials because their unique electric, magnetic, and optical properties. This thesis demonstrated several synthetic strategies for the preparation of rod-, flower-, and cube-like nanomaterials, including Au-Ag and Au-Ag-Hg nanorods (NRs), Au and Ag nanoflowers (NFs), Fe3O4/Au composite nanomaterials, and Cu2O nanocubes. The preparations of Au-Ag and Au-Ag-Hg NRs were based on the deposition of Au, Ag, and Hg atoms that are reduced by ascorbate on the surface of gold NRs under alkaline conditions. Au and Ag NFs were synthesized through the use of a wet chemical method in aqueous solution. Initially the Au or Ag atoms are deposited on Au or Ag nanoparticles (NPs) to form single petals, upon which other petals are formed subsequently at their termini as a result of deposition of Au or Ag atoms. This process repeats until the flower-like nanostructures. Fe3O4/Au composite nanomaterials are grew through deposition of Au atoms on the Fe3O4 NPs (51.5 ± 10.5 nm) under similar conditions for preparation of Au NFs. Cu2O nanocubes with a band gap ~ 2.42 eV were prepared from cupric nitrate in alkaline aqueous solutions containing fructose and ascorbic acid at room temperature. Au-Ag and Au-Ag-Hg NRs having aspect ratios 1.90-4.10 and 2.89-4.10, respectively, possess high extinction coefficients (5.02 × 109 ~ 4.73 × 1010 M-1cm-1) in the UV-vis region. Au and Ag NFs have strong absorptions in the UV-vis and near-IR region and high electronic conductivities (1.97Contents Page 中文摘要 I Abstract III Contents V Table contents VIII Figure contents I Conclusions 155 Publications 157 Chapter 1: Nanomaterials 1 1.1 Introduction 1 1.2 Definition of nanomaterials 2 1.3 Properties of nanomaterials 3 1.4 Preparation method for nanomaterials 4 1.4.1 Hydrothermal Synthesis 4 1.4.2 Sol-gel processes 5 1.4.3 Chemical reduction methods 6 1.5 Applications 7 1.6 Research Motive 9 1.7 References 10 Chapter 2: Impacts that pH and Metal Ion Concentration have on the Synthesis of Bimetallic and Trimetallic Nanorods from Gold Seeds 22 2.1 Abstract 22 2.2 Introduction 23 2.3 Experimental 25 2.3.1 Chemicals 25 2.3.2 Synthesis of gold nanorods 25 2.3.3 Synthesis of bimetallic and trimetallic nanorods 26 2.3.4 Instruments 27 2.4 Results and Discussion 27 2.4.1 Metal ions deposition 27 2.4.2 ICP-MS measurements 30 2.4.3 TEM measurements 31 2.4.4 EDX analysis 32 2.4.5 Hypothesis 32 2.5 Conclusions 33 2.6 References 34 Chapter 3: Anisotropic Syntheses of Boat-Shaped Core–Shell Au–Ag Nanocrystals and Nanowires 46 3.1 Abstract 46 3.2 Introduction 47 3.3 Experimental 49 3.3.1 Chemicals 49 3.3.2 Preparation of gold nanorods 50 3.3.3 Synthesis of boat-shaped core–shell Au–Ag bimetallic nanoparticles 51 3.3.4 Synthesis of core–shell Au–Ag bimetallic nanoparticles in various morphologies 52 3.3.5 Synthesis of bimetallic nanowires 52 3.3.6 Characterization of the nanoparticles and nanowires 52 3.4 Results and discussion 53 3.4.1 TEM measurements 53 3.4.2 Characteristics measurements 54 3.4.3 Mechanism investigations 56 3.4.4 Bimetallic nanowires assembly 58 3.5 Conclusions 61 3.6 References 62 Chapter 4: Preparation and Characterization of Flowerlike Gold Nanomaterials and Iron Oxide/Gold Composite Nanomaterials 71 4.1 Abstract 71 4.2 Introduction 72 4.3 Experimental 74 4.3.1 Chemicals 74 4.3.2 Synthesis of Fe3O4 nanoparticles 75 4.3.3 Synthesis of gold Nanoflowers 75 4.3.4 Synthesis of Fe3O4/Au nanomaterials 76 4.3.5 Conductivity measurements 77 4.3.6 Characterization of nanomaterials 77 4.4 Results and discussion 78 4.4.1 Preparation and characterization of gold Nanoflowers 78 4.4.2 Preparation of Au/Fe3O4 nanmaterials 81 4.4.3 Magnetic and thermal properties 84 4.5 Conclusions 86 4.6 References 87 Chapter 5: Preparation and Characterization of Different Shapes of Silver Nanostructures in Aqueous Solution 99 5.1 Abstract 99 5.2 Introduction 100 5.3 Experimental 103 5.3.1 Chemicals 103 5.3.2 Synthesis of silver nanoflowers 103 5.3.3 Characterization of silver nanoflowers 104 5.3.4 SERS measurements 105 5.4 Results and discussion 106 5.4.1 Structures and properties 106 5.4.2 Growth mechanism 108 5.4.3 Morphology control 109 5.5 Applications 112 5.5.1 Optothermal conversion 112 5.5.2 SERS measurements 113 5.6 Conclusions 114 5.7 References 114 Chapter 6: Preparation and Characterization of Hollow and Filled Cu2O Nanocubes 129 6.1 Abstract 129 6.2 Introduction 130 6.3 Experimental 133 6.3.1 Chemicals 133 6.3.2 Cu2O nanocubes synthesis 133 6.3.3 Different sized Cu2O nanocubes synthesis 133 6.3.4 Instruments 134 6.4 Results and discussion 134 6.4.1 Characterization 134 6.4.2 Preparation parameters 136 6.4.3 Preparation time 138 6.4.4 Absorption properties 139 6.5 Conclusions 142 6.6 References 142 Table contents Table 2-1. Ratios of Elemental Abundances as Measured by ICP-MS for the Au–Ag–Hg Trimetallic NRs.[a] 44 Table 2-2. Physical and Optical Properties of Au–Ag Bimetallic and Au–Ag–Hg Trimetallic NRs. 45 Figure contents Figure 1-1. TEM images of (a) 13 nm of gold nanoparticles, (b) gold nanorods with aspect ratio ~ 3.1, and (c) a silver nanoflower. 15 Figure 1-2. (a) A TEM image of a iron oxide nanoparticles absorbed with several gold nanoparticles. (b) A high-magnification TEM image of absorbed gold nanoparticles in (a). 16 Figure 1-3. A TEM image of hematite nanorices with 494.76 ± 67.86 nm in length and 96.97 ± 13.97 nm in width synthesized from hydrothermal method. 17 Figure 1-4. A TEM image of SiO2 nanoparticles with 38 ± 4.34 nm in diameter synthesized from sol-gel technology. 18 Figure 1-5. A TEM image of Fe3O4 nanoparticles with 7.40 ± 1.14 nm in the diameter synthesized from coprecipitation technology. 19 Figure 1-6. A TEM image of gold nanoparticles with 2.91 ± 0.71 nm in diameter synthesized from chemical reduction method. 20 Figure 1-7. TEM images of various shaped Au-Ag nanorods……………….. 21 Figure 2-1. UV–Vis absorption spectra, plotted as a function of time, for the mixtures containing 10–4 M Hg2+ at pH (a) 8.0, (b) 9.5, and (c) 10.5. 39 Figure 2-2. TEM images of the as-prepared NRs synthesized (a) in the absence and (b) in the presence of Hg2+. All other conditions are the same as those used to obtain Figure 2-1. 40 Figure 2-3. EDX spectra for the as-prepared Au–Ag–Hg trimetallic NRs prepared at pH 8.0. The beam was focused on a single NR (a) at its center and (b) on its side. The size of the beam was 5.0 nm; for correction, half of the beam was focused on a single NR and the other half on the carbon matrix. 41 Figure 2-4. TEM images obtained as a function of time for the as-prepared Au–Ag–Hg trimetallic NRs synthesized in the presence of 10–4 M Hg2+ at pH 8.0. (a) 30, (b) 90, (c) 120 and (d) 150 min. 42 Figure 2-5. TEM images and UV spectra of the Au–Ag–Hg trimetallic NRs prepared at pH 8.0 in the presence of different concentrations of Hg2+. 43 Figure 3-1. TEM images of (a) as-prepared gold NRs and (b) boat-shaped core–shell Au–Ag bimetallic NPs. (c) EDX measurement and (d) UV–Vis spectra of the boat-shaped core–shell Au–Ag bimetallic NPs (solid line) and gold NRs (dash line). 66 Figure 3-2. HR-TEM images of (a) the boat-shaped core–shell Au–Ag bimetallic NPs, (b) the area within the dashed square in (a), and (c) the area within the solid square in (a). 67 Figure 3-3. HR-TEM images of core–shell Au–Ag bimetallic NPs possessing various morphologies: (a), (b) rod-, (c) hook-, (d) W-, (e) glasses-, and (f) boat-shaped NPs. 68 Figure 3-4. (a) TEM image of Au–Ag bimetallic NWs. (b) Magnified TEM image of the area within the square highlighted in (a). (c) Another NW possessing a curved structure. (d),(e) Magnified TEM images of the areas within the two squares highlighted in (c). (f) High-magnification TEM image of the square area highlighted in (d). 69 Figure 3-5. (a) TEM image of aggregated Au–Ag bimetallic NPs. (b) Magnified TEM images of the square area highlighted in (a). (c) High-magnification TEM image of the Au–Ag bimetallic NPs. The NWs were heated at 210 °C for 15 min. 70 Figure 4-1. (a) TEM images of Au NFs, (b) a representative SEM image of Au NFs. (c) An HR-TEM image of one of the petal for a Au NF. The inset is its fast Fourier transform (FFT) pattern. (d) An EDX spectra of Au NFs. (e) The UV-NIR spectra of Au NFs. 90 Figure 4-2. XRD spectra of (a) Au NFs, and (b) Fe3O4/Au composite nanomaterials. 91 Figure 4-3. TEM images of differently-shaped and -sized Au nanomaterials which were collected after a reaction of 1 min. 92 Figure 4-4. HR-TEM image of one of the petals of an Au NF. The inset displays the corresponding FFT pattern. Preparation conditions are similar to that described in Figure 4-1. Reaction time is 1 min. The d spacing of 2.4 Å (white squares) can be successfully analyzed which is in accordance with the Au {111} crystal facet. This result also was supported by the FFT pattern. 93 Figure 4-5. A proposed mechanism for the formation of Fe3O4/Au composite nanomaterials. 94 Figure 4-6. (a) TEM image of Au NFs on Fe3O4 NPs after a reaction time of 7.5 min, (b) Fe3O4/Au composite nanomaterials, and (c) a representative Fe3O4/Au NW taken from the sample in (b). The EDX spectra for (d) dotted (dark image) and (e) solid circled areas in the inset of (d), which is a partial TEM image of a Fe3O4/Au composite nanomaterials. (f) The UV-vis spectra of Fe3O4/Au composite nanomaterials. Reaction times in (b)-(e) were 10 min. 95 Figure 4-7. HR-TEM image of Fe3O4/Au composite nanomaterials. The inset displays the corresponding FFT pattern. The d spacing of 2.5 Å (white squares) can be successfully analyzed which is in accordance with the Fe3O4 {311} crystal facet. The result was also agreed by FFT pattern. 96 Figure 4-8. (a) Magnetization curves of Fe3O4 NPs (--○--) and Fe3O4/Au composite nanomaterials (--●--). (b) Conductivities of Fe3O4/Au composite nanomaterials were estimated from the current bar on the right-hand side of this image. 97 Figure 4-9. Temperature changes of (a) Fe3O4/Au composite nanomaterials in PBS buffer and (b) PBS buffer alone, plotted as a function of the ‘on/off’ time of an alternating magnetic field. The initial temperature is 25.8 oC. 98 Figure 5-1. The TEM images of (a) Ag NFs, (b) a representative Ag NF, and (c) a high magnification HR-TEM image of a Ag NF exhibited in (b). The SEM images of (d) Ag NFs, and (e) a representative silver NF. (f) A selected area electron diffraction pattern of a Ag NF displayed in (b). 120 Figure 5-2. (a) XRD spectrum, (b) EDX spectrum, and (c) UV-vis extinction spectrum for Ag NFs displayed in Figure 5-1. 121 Figure 5-3. (a) The I-V characteristic curve and (b) the SPM image of Ag NFs. The square area highlighted in (b) clearly exhibits a Ag NF. 122 Figure 5-4. TEM images of Ag NSs over the time courses of reaction time (a) 1, (b) 2.5, (c) 5, and (d) 7.5 min. The amplified TEM image in each inset shows a representative Ag NS in each case. Preparation conditions are similar to those described in Figure 5-1. 123 Figure 5-5. TEM images of Ag NSs prepared in a single stabilizer at different concentrations. PEG: (a) 0.078 M, (b) 0.156 M, (c) 0.312 M, and (d) 0.624M. Sodium citrate: (e) 0.125 mM, (f) 0.25 mM, (g) 0.5 mM, and (h) 1 mM. NaAC: (i) 0.0275 M, (j) 0.055M, (k) 0.11 M, and (l) 0.22 M. 124 Figure 5-6. TEM images of Ag NSs that were prepared in different concentrations of tri-stabilizers systems. (a) 0.5X, (b) 2X, and (c) 4X concentrations of three mixing stabilizers. Amplified TEM images in the inset show corresponding representative Ag NSs. 125 Figure 5-7. Impact of capping agents on the formation of different shapes of Ag NSs. 126 Figure 5-8. UV-vis extinction spectrum for (a) snowflake- and (b) spike-liked Ag NSs. 127 Figure 5-9. SERS spectra of (a) 100 nM, and (b) 10 nM R6G molecules in the presence of snowflake-shaped Ag NSs, and (c) 10 mM R6G in the absence of Ag snowflakes. 128 Figure 6-1. (a) TEM image of filled Cu2O nanocubes. (b) HR-TEM image of a representative filled Cu2O nanocube. (c) high-magnification HR-TEM image of a Cu2Onanocube exhibited in b. The inset in Figure 6-1 (c) is the FFT pattern of a Cu2O nanocube. 146 Figure 6-2. (a) EDX spectrum and (b) XRD pattern of Cu2O nanocubes. 147 Figure 6-3. (a) TEM image of a Cu2O nanocube prepared by applying at a Pt-C NPs shadowing technology. (b) Schematic illustration for h, S, and θ that are used for calculation of the thickness of Cu2O nanocubes. 148 Figure 6-4. TEM images of Cu2O nanocubes at different [Fructose]/[Cu2+] ratios; (a) 16.6, (b) 133.2, and (c) 266.4 at the fixed concentration of Cu2+ ~ 2.5 × 10-4 M. 149 Figure 6-5. TEM images of hollow Cu2O nanocubes prepared at reaction times of (a) 1, (b) 15, (c) 30, and (d) 45 min, respectively. 150 Figure 6-6. Schematic illustration of the formation of Cu2O nanocubes from “hollow” to “filled” structures. 151 Figure 6-7. Absorption spectrum of Cu2O nanocubes. The inset shows the representative plot of (αEphoton)2 verus Ephoton for direct transition. 152 Figure 6-8. Luminescence spectrum of Cu2O nanocubes. 153 Figure 6-9. (a) Absorption spectra of Cu2O nanocubes in the presence of [Fructose]/[Cu2+] at the ratios of 16.6, 133.2, and 266.4 at the fixed concentration of Cu2+ ~ 2.5 × 10-4 M. (b) The corresponding luminescence spectra. 1544393838 bytesapplication/pdfen-US奈米材料金-銀-汞奈米棒花狀金奈米材料花狀銀奈米材料金-鐵複合奈米材料方塊狀氧化亞銅奈米粒子nanomaterialsAu-Ag nanorodsAu-Ag-Hg nanorodsnanoflowersFe3O4/Au composite nanomaterialsCu2O nanocubes[SDGs]SDG7thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/51919/1/ntu-96-D92223002-1.pdf