本文選題：摻雜碳量子點　切入點：微波合成　出處：《南京大學》2017年碩士論文　論文類型：學位論文

【摘要】：碳量子點(CQDs)是新型碳納米材料,熒光強度高且穩(wěn)定,對生物體和環(huán)境無害。碳量子點可以與無機物或有機物復合,在生物探針和催化等方面有著廣泛應用前景,近年來已經(jīng)成為研究熱點。目前的研究主要是對碳量子點進行非金屬元素摻雜,改變其電子結構和光學性質,但通常直接焙燒或水熱合成法存在合成溫度高,時間長以及摻雜量低等問題。鑒于此,我們發(fā)展了高效微波輔助熱合成法,基于"自下而上"合成路徑一步合成了兼具高熒光發(fā)光性能和催化活性的碳量子點。本論文研究包括兩部分:第一部分工作,研制了高含量摻雜氮硫的碳量子點(N,S-CQDs),探討了氮硫摻雜碳量子點的合成機理、熒光發(fā)光特性及類酶催化活性。第二部分工作采用甲基咪唑摀四氟硼酸鹽離子液和碳源前驅體研制了硼、氮和氟三元摻雜碳量子點(B,N,F-CQDs),研究了前驅體比例和反應時間對硼、氮和氟摻雜碳量子點熒光性能的影響,獲得了具有高熒光量子效率的碳量子點。主要研究成果如下:Ⅰ.N,S-CQDs的合成及類酶催化活性的研究以檸檬酸為碳源、硫脲為氮源和硫源,通過微波固相熱合成方法在50秒內(nèi)合成具有高氮和硫摻雜水平的氮、硫共摻碳量子點N,S-CQDs。研究摻雜碳量子點合成機理,發(fā)現(xiàn)硫脲作為弱堿可以加快反應速率,降低碳化溫度,減少反應損失,從而提高了摻雜水平。對摻雜碳量子的光學性質和類酶催化活性的研究發(fā)現(xiàn)相對于未摻雜的CQDs,N,S-CQDs具有更高的熒光量子效率和類酶催化活性;XPS研究發(fā)現(xiàn)進入共軛骨架的吡啶結構N是主要摻雜類型,是類酶催化活性的中心,在邊緣的吡咯結構N是作為熒光發(fā)射中心,從而實現(xiàn)了樣品同時具有高的酶模擬催化活性和光致發(fā)光量子產(chǎn)率。Ⅱ.三元摻雜CQDs的合成采用離子液體1-丁基-3-甲基咪唑摀四氟硼酸鹽([BMIm][BF4])和檸檬酸為碳源,一步合成了 F摻雜CQDs。獲得直徑范圍在4nm至5nm的粒徑均一的三元摻雜碳量子點B,N,F-CQDs,其最高熒光光量子產(chǎn)率為41.8%;對各摻雜元素的濃度和結構的分析發(fā)現(xiàn),同時存在C-F半離子鍵和C-F共價鍵,推測氟作為熒光發(fā)射中心對材料的發(fā)光性能起到關鍵作用。
[Abstract]:Carbon quantum dots (CQDs) are novel carbon nanomaterials with high fluorescence intensity and stability, which are not harmful to organism and environment. Carbon quantum dots can be combined with inorganic or organic compounds, and have wide application prospects in biological probe and catalysis. In recent years, it has become a research hotspot. The current research is mainly about doping carbon quantum dots with non-metallic elements to change their electronic structure and optical properties, but the synthesis temperature is usually high in direct calcination or hydrothermal synthesis. In view of this, we have developed a high efficiency microwave assisted thermal synthesis method. Based on the "bottom-up" synthesis path, carbon quantum dots (QDs) with high luminescence and catalytic activity were synthesized in one step. Carbon quantum dots with high content of nitrogen and sulfur were prepared. The synthesis mechanism of carbon quantum dots doped with nitrogen and sulfur was discussed. In the second part, boron, nitrogen and fluorine ternary doped carbon quantum dots were prepared by using methyl imidazolium tetrafluoroborate ionomer and carbon source precursor. The effects of precursor ratio and reaction time on boron were studied. Carbon quantum dots with high fluorescence efficiency were obtained by the influence of nitrogen and fluorine-doped carbon quantum dots. The main results are as follows: 鈪，

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