Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, P. R. China.
National Engineering Technology Research Center for Colloidal Materials, Shandong University , Shanda Nanlu No. 27, Jinan 250100, P. R. China.
ACS Appl Mater Interfaces. 2018 Jan 31;10(4):3955-3963. doi: 10.1021/acsami.7b16316. Epub 2018 Jan 18.
Metal nanoclusters (NCs) have been engineered as a new kind of luminescent material, whereas the application of metal NCs in aqueous solution was subjected to great limitations owing to their poor solubility, stability, and strong luminescence quenching in a single-molecule state. Herein, facile supramolecular self-assembly strategy was carried out to enhance the luminescence of Ag(I) NCs (Ag-NCs) through multiple electrostatic interactions with polyethyleneimine (PEI). Functional colloid aggregates of Ag-NCs such as nanospheres and nanovesicles were formed along with the enhanced emission because of the formation of compact-ordered self-assemblies, which effectively restricted intramolecular vibration of the capping ligands on Ag-NCs to diminish the nonradiative decay. All those could block energy loss and facilitated the radiative relaxation of excited states which ultimately induced an aggregation-induced emission (AIE) phenomenon. Furthermore, the luminescent Ag-NCs/PEI nanovesicles are pH-responsive and show a superior fluorescent sensing behavior for the detection of Al with a limit of detection low to 3 μM. This is the first report about AIE of silver NCs with polymers in aqueous solution. This work sheds light on the controlled NCs-based supramolecular self-assembly and the NCs-based functional materials, which will be well-established candidates in controllable drug delivery, biomarkers, and sensors in aqueous solution.
金属纳米团簇 (NCs) 已被设计为一种新型发光材料，然而由于其在单分子状态下的溶解度差、稳定性差和强荧光猝灭，金属 NCs 在水溶液中的应用受到了很大的限制。在此，通过与聚乙烯亚胺 (PEI) 的多重静电相互作用，进行了简便的超分子自组装策略，以增强 Ag(I) NCs (Ag-NCs) 的发光。由于形成了紧密有序的自组装体，Ag-NCs 的功能胶体聚集体（如纳米球和纳米囊泡）形成，同时伴随着发射增强，这有效地限制了 Ag-NCs 上配体的分子内振动，从而减少了非辐射衰减。所有这些都可以阻止能量损失，并促进激发态的辐射弛豫，最终导致聚集诱导发射 (AIE) 现象。此外，发光的 Ag-NCs/PEI 纳米囊泡对 pH 具有响应性，并表现出优异的荧光传感行为，用于检测 Al，检测限低至 3 μM。这是关于聚合物水溶液中银 NCs 的 AIE 的首次报道。这项工作为基于可控 NCs 的超分子自组装和基于 NCs 的功能材料提供了启示，它们将成为水溶液中可控药物输送、生物标志物和传感器的候选材料。
