High-Performance Electrochemical Sensor Based on Layer-by-Layer Assembly of [CQDs-PAH] Thin Film for Lead Ions Detection

According to the extraordinarily excessive toxicity of lead ions (Pb 2+ ) to humans even by tiny dose nowadays, the development of transportable and pocketed electrochemical sensor to detect tiny amount of Pb 2+ ions with excessive sensitivity is in a pressing need. In this study, the carbon quantum dots (CQDs) synthesized from glutathione (GSH) were applied as the sensing materials for sensitive lead ions detection via square wave voltammetry (SWV) analysis, which can specific adsorb lead ions owing to the abundant functional group especially sulfhydryl. To enhance the performance of this sensing strategy, we constructed layer-by-layer [LBL] assembled [CQDs-PAH] thin films, the thin films performed a LBL three-dimensional network structure, which provided larger contact area for CQDs and Pb 2+ ions, and also accelerated electron transfer of the active materials, thus improved the electrochemical sensing performance efficiently. The [CQDs-PAH] thin films would offer a new paradigm to design high-efficient electrochemical sensor for Pb 2+ ions detection. CQDs synthesized from glutathione showed abundant groups, uniform size and excellent electrochemical performance. As-prepared CQDs could adsorb Pb2+ ions specifically due to their abundant functional groups, especially sulfhydryl. Layer-by-layer assembled [CQDs-PAH] thin film exhibited a three-dimensional network structure, provided a larger contact area and accelerated the electron transfer efficiency.