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  • 學位論文

石墨烯量子點在光催化降解抗生素與鈣鈦礦太陽能電池下轉換裝置之應用

Application of Graphene Quantum Dots in Photocatalytic Degradation of antibiotics and Down-conversion Devices of Perovskite Solar Cells

指導教授 : 劉偉仁

摘要


本研究中利用兩種不同的原料及方法分別製備出不同的石墨烯量子點(Graphene quantum dots, GQDs)並應用於不同領域,研究中將探討兩種不同的GQDs在光降解領域與太陽能電池之應用。 論文中第一部分將利用高溫燒結法製備石墨烯量子點(Graphene quantum dots,簡稱GQDs)並透過在氧化鋅(ZnO)生成時調整添加的比例,並得到一最佳化參數,使GQDs嵌入ZnO中以減少遮蔽效應,降低純ZnO電子電洞對復合的能力。藉由熱重分析儀(Thermogravimetric Analyzer,簡稱TGA)可測得石墨烯量子點嵌入ZnO中的含量為32.2%;接著我們將此複合物應用在光催化降解咪唑尼達(Metronidazole, MNZ)實驗中,透過高效液相層析儀(High performance liquid chromatography, HPLC)進行降解濃度的測量,結果顯示此降解反應為一階反應,且有添加GQDs之ZnO相較於未添加者,其k值為0.157 s-1和未添加GQDs之k值0.090 s-1相比,其降解效率提升了74.4%。證明添加GQDs能有效抑制ZnO在UV激發下電子電洞對復合的能力,因此比複合材料在降解廢水上具有很大的應用潛力。 論文中第二部分則是以水熱法製備硼摻雜石墨烯量子點,透過硝化芳香族化合物芘(Pyrene)合成前驅物三硝基芘(1,3,6-Trinitropyrene, TNP)並使其產生活性反應點,並透過溶劑熱法進行高溫熱解反應產生大面積多環芳香烴,並模擬一缺陷值相較於石墨烯更低的結構,透過拉曼光譜測試可得知其ID/IG僅1.01。接著加入硼酸進行硼摻雜以提升其量子效率及發光特性,可得一粒徑大小為5 nm的紅光石墨烯量子點,透過螢光光譜儀可得其放光波長為621 nm,再透過吸收光譜可得知,其吸收範圍透過朋元素的摻雜後很明顯地得到提升。再對其進行穩定性測試,經過一個月的測試發現有摻雜硼的BGQDs在大氣條件下仍可保持約90%的螢光保留率。最後,我們利用BGQDs的下轉換特性將其應用於保護鈣鈦礦太陽能電池不受紫外光的破壞之研究。從元件測試後的數據能得知,其光電流從20.6 mA/cm2提升至22.9 mA/cm2,且在衰退測試中能夠將僅搭載玻璃基板的衰退速率由每小時-7.7 %降低至每小時-4.4 %,證明此材料在保護鈣鈦礦太陽能電池的應用中具有很大的潛力。

並列摘要


In this study, we propose graphene quantum dots (GQDs) by two different approaches and apply GQDs for photocatalytic degradation and perovskite solar cells. In the first part, we synthesize GQDs by a high-temperature sintering method derived from citric acid and urea. Via combining ZnO and GQDs with different ratio, we try to apply composition-optimized ZnO/GQDs composite on photocatalytic degradation of Metronidazole (MNZ). The result show that the degradation of MNZ is a pseudo-first order reaction. The rate constants of pure ZnO and composition-optimized ZnO/GQDs composite are 0.090 s-1 and 0.157 s-1, respectively. The performance of degradation is dramatically enhanced by74.4%. The reason was due to improved separation ability of electron-holes pairs. So, this composite material has great application potential in the degradation of antibiotic wastewater. In the second part, we prepared GQDs by a hydrothermal method derived from 1,3,6-Trinitropyrene (TNP). The average particle size of GQDs and BGQDs are 3.6 nm and 5.1 nm. The Raman spectrum test shows that the ID/IG of GQDs and BGQDs are 0.99 and 1.01. By XPS test, we could find C-B and BCO2 bonding. Through the fluorescence spectrometer, the emission wavelength of 621 nm could be obtained. After the stability test, it was found that BGQDs doped with boron could still keep about 90% of the PL retention rate in atmosphere. Through particle size analysis, its particle size is 5 nm. Finally, we proposed BGQDs to applied in down-conversion device to protect perovskite solar cells. After current density-voltage test, the photo-current JSC was increased from 20.6 mA/cm2 to 22.9 mA/cm2. In the decay test, the decay rate of only the glass substrate can be reduced from -7.7 %/h to -4.4%/h, which proves that this material has great potential in the application of down-conversion device.

參考文獻


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