發光貴金屬及碳奈米材料之合成及其應用

Abstract

發光奈米材料具有高靈敏度、選擇性、以及高光穩定性之特性，故具有應用於生物感測器、細胞顯影劑及顯示器等之潛力。相較於傳統發光半導體量子點使用有毒重金屬為前驅物，此研究主要是以綠色化學方法來合成貴金屬奈米團簇(nanoclusters)以及碳奈米量子點，並應用於不同領域例如環境樣品中重要離子檢測、發光薄膜和催化劑等。整篇論文共分成七個章節，第一章回顧貴金屬奈米團簇和碳奈米量子點的背景知識包含合成、光學性質以及已開發之應用。第二章節，合成可調控放光之氧化鋁奈米及金奈米團簇複合材料並用於改善金奈米團簇的純化過程。經純化的氧化鋁金奈米團簇對於銀離子有更佳的靈敏度，其偵測極限降低了約六倍(從10 nM 降低到1.5 nM)。第三章，於有機溶劑中合成銅奈米團簇聚集體，並進一步研究溶劑對銅奈米團簇”聚集-誘導放光”之影響。此銅奈米團簇聚集體更被用來檢測硫化氫，其偵測極限為500 nM，並被證明能用來分析環境中溫泉水的硫化氫濃度。在第四章，以一鍋合成法(one-pot)來合成金銅奈米團簇，此金銅奈米團簇的螢光對於不同的酸鹼程度會有不同的螢光強度，具有作為pH 感測器潛力。此外，此金銅奈米團簇可用來催化有機染料還原反應。第五章，開發一快速合成法來合成牛血清蛋白金奈米團簇。並利用質譜法以及螢光光譜法被來研究牛血清蛋白金奈米團簇的生長機制。更進一步，牛血清蛋白金奈米團簇被用來檢測汞離子其靈敏度為4 nM。第六章，以一鍋水熱合成法(one-pot hydrothermal route)合成有機矽修飾之碳奈米量子點，此矽修飾之碳奈米量子點的螢光對於溫度293-343 K具有線性響應，此外藉由矽氧鍵(Si–O–S)的作用力，此矽修飾之碳奈米量子點能輕易地被均勻塗覆在玻璃上。第七章，以有機矽修飾之碳奈米量子點為前驅物合成發光矽碳奈米與二氧化矽的奈米複合物(SiC-dots/SiO2 nanocomposites)。藉由控制加熱時間，可合成藍色、綠色、黃褐色放光之矽碳奈米與二氧化矽的奈米複合物。此矽碳奈米與二氧化矽的奈米複合物更被運用於彩色玻璃、電催化材料以及熱微影術。

Photoluminescent nanomaterials exhibit great potential for sensing, imaging and visual display because they have advantages of high selectivity and sensitivity, and outstanding photostability. In comparison with conventional semiconductor quantum dots, which use heavy metal ions as precursors, we have developed a series of green approaches for preparation of photoluminescent noble metal and carbon nanomaterials. As-prepared photoluminescent nanomaterials were applied in various fields such as detection of important ions in environmental samples, fabrication of photoluminescent thin films and as catalysts. This dissertation is structured in seven chapters. In Chapter 1, the background of noble metal nanoclusters (NCs) and C-dots including their synthetic routes, optical properties and applications is reviewed in detail. In Chapter 2, alumina nanoparticle supported Au NCs with tunable emission wavelengths were prepared to simplify the purification process. Purified Al2O3 NPs@Au NCs revealed six-fold better sensitivity (from limit of detection (LOD) 10 nM to 1.5 nM) towards silver ions. In Chapter 3, luminescent Cu NC aggregates were prepared in the presence of organic solvent. The relation between aggregation-induced emission behavior and organic solvent was investigated. As-prepared Cu NC aggregates were utilized to detect hydrogen sulfide (LOD: 500 nM), and their practicality was validated by detection of hydrogen sulfide in hot spring water samples. In Chapter 4, a one-pot approach to synthesize bimetallic AuCu NCs was developed. The AuCu NCs revealed interesting pH-dependent photoluminescent behavior, and exhibited their potential as pH sensors and organic dye reduction catalysts. In Chapter 5, a facile method to prepare bovine serum albumin gold nanoclusters (BSA-Au NCs) is reported. The growth mechanism of BSA-Au NCs was studied by mass spectroscopy and photoluminescence measurements. The work laid solid foundation for synthesis of dual-emission metal NCs. In Chapter 6, organosilane-functionalized carbon nanodots (SiC-dots) were synthesized by a simple one-pot hydrothermal route. The photoluminescence of SiC-dots revealed reversible temperature response (293–343 K). Through Si–O–Si bonding, temperature-sensitive photoluminescent SiC-dot films could be easily fabricated on glass substrates without aggregation. In Chapter 7, SiC-dots/SiO2 nanocomposites were prepared from SiC-dots (in Chapter 6). By controlling the heat treatment time, blue, green, and tan (yellow-brown) photoluminescent SiC-dots/SiO2 nanocomposites were achieved. The potential applications for colourful windows, electrocatalysis and lithographic patterning of SiC-dots/SiO2 nanocomposites were demonstrated.