金-石墨烯電組裝混成電極開發及其應用於低濃度多巴胺檢測

Electrically-Assisted Assembly of Hybrid Gold-Graphene Electrodes and Their Application in Sensing of Dopamine at Low Concentrations

鄭勝勻

指導教授 ： 洪健中

國立清華大學/工學院/動力機械工程學系/碩士(2013年)

摘要

本論文研究利用電沉積的方式組裝奈米材料金粒子以及石墨烯於電極上，藉此方式開發出具三維結構之電極，三維結構的形成能增加電極的工作表面積，並佐以生醫微機電技術整合製作一微流道感測晶片，應用於多巴胺的感測上，期望藉由此高靈敏性的電極能夠在低濃度的環境下達到檢測的目的。
在電沉積組裝奈米材料的製程上，本研究對於金粒子及石墨烯兩種材料的沉積參數做了一系列的探討，對於金粒子的沉積其參數探討電壓、頻率以及時間，而石墨烯則探討其表面改質之活性劑以及沉積時間，在得到這兩種材料的最佳化沉積參數後，再混成沉積這兩種材料，由於金粒子能夠形成高深寬比的三維結構型態，石墨烯片狀的堆疊，結合這兩者的特點所得到的混成電極，將其與金粒子以及石墨烯電極作為對照比較，藉由表面型態、厚度、電性、阻抗以及附著性的探討得知電極的資訊，結果得知金-石墨烯混成電極有較好的特性。
將所開發三維結構之高靈敏感測器其應用於多巴胺的檢測上，由實驗的結果得知有金粒子沉積的電極因三維結構增加表面積大幅的關係，感測訊號電流與未修飾的裸金電極相比可增加約70倍；而濃度感測上則得知有石墨烯沉積在電極的最外層對於多巴胺有較好的感測結果，主要是因為石墨烯與多巴胺的苯環結構能夠產生π-π相互作用，藉此捕捉住多巴胺分子，且金-石墨烯混成電極因石墨烯沉積在金粒子所形成的高深寬比三維結構中，相比於沉積在平坦的裸金電極上能夠更大幅度地沉積，因此感測結果較石墨烯電極的要來的好，而感測的線性區間為2至20 ppb，偵測極限為2 ppb。
本研究所開發之金-石墨烯電組裝混成電極經由三維結構的形成而增加電極的工作表面積，除了對於生醫感測上能增加靈敏性外，對於電極的介面需要增加表面積來強化效能特性的燃料電池、超級電容器等也都具有應用的潛力。

關鍵字

電沉積 ； 三維結構 ； 混成電極

並列摘要

In this research, a hybrid electrode with three-dimensional nanostructures has been developed, fabricated, and characterized. The nanogold and graphene were assembled on electrodes by electrodeposition to form three-dimensional nanostructures that increased surface area of working electrodes. Finally, microfluidic chips with the developed electrodes have been applied for sensing of dopamine at low concentrations.
In this research, the deposition parameters of nanogold and graphene, such as voltage, frequency, time, and surfactant, have been investigated and optimized systematically. The developed technology takes advantage of porous nanostructures, which are formed by gold nanoparticles. Then, graphene are deposited layer by layer on the gold nanoparticles to make the hybrid electrodes. By the measurements of surface morphology, thickness, electric property, resistance, and adherence, we can prove that the gold-graphene hybrid electrode has better characteristics than pure nanogold electrode and pure graphene electrode.
According to the experimental results, the sensing currents increase about 70 times, because the surface area of nanogold deposited electrode substantial increase by the fabricated three-dimensional nanostructures. In dopamine detection, due to π-π interaction between phenyl structure of dopamine and two-dimensional planar hexagonal carbon structure of graphene, dopamine can be captured on the electrode surface. In addition, the sensing results of gold-graphene hybrid electrode are better than the graphene electrode due to the increased surface area. The limit of detection is 2 ppb, and linear range is 2 to 20 ppb.
The gold-graphene hybrid electrode has larger working surface area by formation of three-dimensional nanostructures. In future, the developed technology could be applied to fuel cells and supercapacitors.

並列關鍵字

electrodeposition ； three-dimensional nanostructure ； hybrid electrode

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