表面電漿共振於常溫NO氣體感測晶片之研發

Abstract

表面電漿共振(Surface Plasmon Resonance, SPR)是一種光學式的生物/化學感測器，具有良好的靈敏度、非接觸式、即時反應、及可平行檢測等優點，已在生物分子與化學的檢測元件上成為非常重要之檢定方式。本實驗藉電化學循環伏安法(Cyclic Voltammetry, CV)以不同氧化電位、掃瞄速度，和掃描圈數的聚二氧乙烯噻吩(PEDOT)沉積於SPR晶片上。藉由最佳化的校正參數來達到理想的表面電漿共振曲線與靈敏度，未來於一氧化氮檢測疾病診斷以及環境氣體監視應用。 在本研究中以電化學製備PEDOT為感測薄膜，相較於必須操作在高溫的金屬半導體或金屬複合物，它工作在常溫，具有高導電度、成本低廉和容易製造等優點，於一氧化氮感測實驗中，我們使用的晶片為氧化電位為0-0.88伏，掃瞄速度為200mV/s，掃描圈數為30圈的PEDOT晶片，在定角度43.2°下，依序通入100、50和25ppm的一氧化氮(NO)於常溫下，反射強度約為0.707、0.407和0.232，相關係數為0.96，以及實驗最低偵測極限約為8ppm；觀察不同氣體對晶片的反應，通入100、50和25ppm的二氧化氮(NO2)，反射強度分別為0.55、0.32和0.17，由結果顯示PEDOT的晶片，對一氧化氮的強度變化比二氧化氮的反應大,且反應時間較快。本研究已成功完成在常溫下量測的光學式氣體感測器，與薄膜特性結合之表面電漿共振氣體感測器已具有快速、即時反應、常溫以及高靈敏度等良好特性，於未來可望成為一低功率之光學式表面電漿共振氣體感測裝置。

A study was conducted to use the cyclic voltammery (CV) method to deposit polymer on the SPR chips at different potential range, scanning cycles, and scanning rates. We proposed to design SPR sensing chip combined with the Poly(3,4-ethylenedioxythiophene) (PEDOT) thin film as a novel optical SPR gas sensor. Depending on the optimal design of PEDOT sensing film, it provided better SPR curve and sensitivity and be able to apply to application of nitric oxide (NO) detector, which is a critical index in asthma diagnostic, and environmental toxic gas sensor in the future. In this study, we used the electrochemical system to prepare the PEDOT thin film. PEDOT as a sensing film which working at room temperature, as compared to the need to operate at a high temperature metal or metal compound semiconductor, and it have advantage of high conductivity, low-cost and easy to manufacture, etc... In the experiment the chip we use with sweeping voltage from 0v to 0.88v, scan rate 200mV/s for 30 cycles. At the degree of 43.2°, the reflectance intensity are 0.707, 0.407, and 0.232 at different concentration of 100, 50, 25ppm NO gas and 0.55, 0.32, and 0.17 for NO2 gas, the detecting limit of this thin-film sensing chip is about 8 ppm of NO gas at room temperature, correlation coefficient, R2, of NO gas concentration versus SPR angle shift is 0.96; the result shows the intensity for NO gas sensing is larger than NO2 gas and faster reaction time. In the experiments of this thesis, we have successfully combined the PEDOT thin film with the SPR sensor to serve as a nitric oxide gas detector, this novel type gas sensor provides several advantages such as fast, reversible, room temperature and high sensitivity and is able to serve as an optical surface plasmon resonance gas sensor.