距離調控式奈米銀增強螢光的感測機制應用於紙片型光學感測器之研製

本研究使用化學合成法將市售的水相螢光分子轉相成可溶於二氯甲烷的有機相螢光分子，並以奈米金屬增強螢光效應的原理為基礎，於螢光材料中混入有機單層分子膜包覆的奈米銀團簇，最後做成以螢光反應來偵測有機氣體的紙片型感測器。本研究使用市售之綠光感測器搭配雙低通濾波電路所組成的微小化感測器，與光譜儀相比，不僅大幅地降低實驗成本，對於有機氣體偵測的螢光訊號反應也得到有效的放大。為優化實驗條件，本研究做了三種影響因素的比較，分別選用不同碳鏈長度的硫醇來包覆奈米銀粒子、不同螢光反射底板、調整奈米銀與螢光的混合比例，接著將具有最佳化條件的組合，用於偵測8種不同官能基的有機氣體，結果顯示螢光訊號反應有良好的穩定性與可逆性，線性迴歸係數大於0.99，且實驗證實，混入有機相奈米銀粒子，可以有效提升有機氣體偵測的靈敏度，偵測極限值介於11.4 ppm（butanol）到346.8 ppm（octane、toluene）之間。透過作用力的分析，了解到有機氣體的極性或氫鍵等特性會影響螢光反應，也從octane等低極性氣體的測試中證實，螢光反應確實來自於螢光團基與奈米銀粒子之間的距離改變。

關鍵字

MPC材料；局部表面電漿共振；金屬增強螢光效應；揮發性有機化合物

並列摘要

This research reports a novel paper-based optical device as a gas detector for volatile organic compounds（VOCs）. This gas-sensing mechanism is based on the Metal Enhanced Fluorescence（MEF）effect. We successfully synthesized an organic fluorescent molecule which can be mixed with a monolayer protected silver nano-cluster（MPC）. In this work, we combined a green-color sensor and a dual low-pass filter circuit into a miniaturized fluorescence sensor. Compared with a spectrometer, our sensor not only greatly reduces the experimental cost, but also effectively amplifies the fluorescence signal response for organic gas detection. In order to optimize the experimental conditions, this study made a comparison of three influencing factors, which are: the selection of thiols with different carbon chain lengths to protect silver nanoparticles, different fluorescent reflective substrates to enhance the signal strength, and adjusting the mixing ratio of silver nanoparticles to fluorescents. Next, we chose the optimized conditions of the material, and used it to detect 8 kinds of organic gases with different functional groups. These results show that the fluorescent signal reaction has good stability, reversibility, and a statistically significant linear relationship.The detection limit is between 11.4 ppm (butanol) and 346.8 ppm (octane, toluene). By analyzing the intermolecular force, we found that the polarity and hydrogen bond of the organic gas will affect the fluorescence reaction. It’s also confirmed from the test of the low-polarity gas octane, that the fluorescence reaction does indeed result from the change in the distance between the fluorophore group and the silver nanoparticle.