本研究利用溶劑熱法來合成碳量子點，以鄰苯二胺(o-Phenylenediamine, oPD)作為碳量子點的前驅物，並藉由TiO2奈米粒子的添加，以非勻相成核生長系統來進行反應，試圖合成具有高螢光量子產率的碳量子點。實驗中，除了使用一般的TiO2奈米粒子外，亦將TiO2以不同的分子改質，包括NH4HCO3、NH3(g)、(3-Aminopropyl)trimethoxysilane與硼酸，分別命名為NH4HCO3¬-TiO2、NH3-TiO2、NH2-TiO2、B0.5- TiO2。所製備出的碳量子點以紫外-可見光光譜儀(UV-vis)、螢光光譜儀、高解析穿透式電子顯微鏡(HR-TEM)、傅立葉轉換紅外光譜儀(FTIR)、X射線光電子能譜(XPS)的來分析其物性，了解其這些性質與製備方法及螢光量子產率的相互關係。實驗結果發現若以勻相成核生長的系統反應，合成出的碳量子點(oCD)之螢光量子效率約為15.66%，而加入純TiO2奈米粒子進行異相成核生長時，反應所需活化能會下降，所製備的碳量子點(TiO2-oCD)的螢光量子效率提升至63.96%。若利用NH4HCO3-TiO2於反應中，合成之碳量子點(NH4HCO3-TiO2-oCD)可以獲得最高的螢光量子產率85.92%，而其他改質後的TiO2則無顯著的效果。而由XPS分析得知NH4HCO3-TiO2可以提供碳量子點N、O元素，導致螢光量子產率提升。

In this study, carbon quantum dots(CQDs) were synthesized by solvothermal method. o-Phenylenediamine (oPD) was used as the precursor of CQDs preparation, and TiO2 nanoparticles were added to form a heterogeneous nucleation growth system, to synthesize CQDs with high fluorescence quantum yield (QY). In the experiment, in addition to using general TiO2 nanoparticles, TiO2 was also modified with different molecules, including NH4HCO3, NH3(g), (3-Aminopropyl)trimethoxysilane and boric acid, named NH4HCO3-TiO2, NH3(g)-TiO2, NH2-TiO2, B0.5-TiO2. The prepared CQDs were analyzed by Ultraviolet–visible spectroscopy (UV-vis), Fluorescence spectrometer, High-resolution transmission electron microscope (HR-TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS). And through analyzing the physical properties, we can understand the relationship between the fluorescence QY and the characteristics of CQDs. The experimental results show that the fluorescence QY of the CQDs synthesized in homogeneous system (oCD) is 15.66%, while the QY of CQDs (TiO2-oCD) prepared in heterogeneous increases to 63.96% due to the reducing of energy barrier. If NH4HCO3-TiO2 is used in the reaction, the synthesized carbon quantum dots (NH4HCO3-TiO2-oCD) can obtain the highest fluorescence quantum yield 85.92% with emission 498 nm, while other modified TiO2 have no significant effect. The XPS analysis shows that NH4HCO3-TiO2 can provide carbon quantum dots N and O elements, resulting in an increment of the fluorescence quantum yield.

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