由於光致發光、可溶性、低毒性及生物可融性等性質，使石墨烯量子點儼然成為矚目的焦點，並應用於生物感測、藥物運輸及癌症治療等。然而，傳統合成石墨烯量子點的方法面臨著一些困難，例如複雜的操作、耗時、高溫需求等。不僅如此，困難還包括了調控其發射來進行感測系統的應用。另一方面，銅離子被報導在環境與人體中都占據了很重要的地位，因此使用石墨烯量子點基於光致發光的銅離子感測器展現了它的便利性、快速的回應、高靈敏及選擇性。然而，雖然這樣的感測器已被報導，卻很少有人探討如何有效的改善感測以及探討石墨烯量子點的特性與感測表現之間的關係。
因此，我們呈現了綠能且精巧的合成與感測，使用大氣常壓微電漿的方式以澱粉為原料合成可調控發射的石墨烯量子點，並使用它來進行光致發光的銅離子感測。大氣常壓微電漿是在電極中利用氣體的方式放電，可在大氣常壓下穩定的操作。而我們可以透過簡單的調整電漿電流、澱粉的濃度以及NaOH比例來調控石墨烯量子點的光致發光發射。而不同發射的石墨烯量子點會有各自的含氧官能基、能階結構以及量子產率。此外，我們也探討了激發依賴性，可以藉由選擇特定的激發波長用於改善光致發光感測，其後，我們探討了石墨烯量子點的不同特性對光致發光感測的影響，並在最後探討如果藉由合成參數調控來製備更具有更好光致發光感測的石墨烯量子點。

Recently graphene quantum dots (GQDs) have been shown with superior tunable optoelectronic properties including photoluminescence (PL) properties, GQDs demonstrate exceptional solubility, cytotoxicity and biocompatibility, making them useful in biomedical applications including biosensing, drug delivery, and cancer therapy. However, the conventional approaches to prepare GQDs are encountered some difficulties, which is inclusive with complicated operation, time consuming inefficiency, and high temperature required. Nevertheless, challenges still remain with respect to fabrication of tunable emission wavelength that could be construct multifunctional sensing systems. On the other hand, Cu2+ plays a critical role in the areas of environmental systems and human body. Photoluminescence-based Cu2+ detection using GQDs have been recently reported due to the simplicity, rapid response, superior sensitivity and selectivity. However, few people explored how to improve the sensing performance efficiently and compared the sensing results between GQDs with different properties.
Hence, we presented a green and facile microplasma-assisted synthesis of emission-tunable GQDs from biomass (i.e. starch) for PL-based copper ion sensing. Microplasmas are defined as gaseous discharges formed in electrode geometries, which can be operated stably with an aqueous solution at atmospheric pressure. Significantly, the PL emissions of GQDs could be tuned by simply adjusting the currents of microplasmas, the concentrations of precursor and the ratio of NaOH, those kinds of GQDs would present specific band structures, oxygen functionalities and quantum yields individually. Moreover, we explored that excitation-dependent properties can improve the PL sensing performance efficiently by choosing specific excitation, and we studied on the influence of GQDs with different properties on sensitivity and excitation-dependent properties. In the end, we reported which parameter of GQD synthesis would lead to the GQD properties which resulted in better PL sensing performance.

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