Rational Design Copper Nanocluster-Based Fluorescent Sensors towards Heavy Metal Ions: A Review

Recently, copper nanoclusters (CuNCs) have attracted great research interest for their low synthesis cost, wide application, and easy functionalization. Until now, CuNCs have been developed and applied in multi-fields such as sensing, catalysis, light-emitting diode manufacturing, and cell imaging. Furthermore, the application of heavy metal ions (HMIs) detection is also regarded as a major part of fluorescence sensing and the necessity of detecting the makeup of HMIs (Ag+, Te3+, Co2+, Se6+, Hg2+, Mn2+, etc.) in organisms and the environment. This has promoted the development of CuNCs in fluorescence sensing. This paper reviews the research progress of CuNCs detection in HMIs, which can be divided into four parts. The synthesis and characterization of CuNCs are first described. Then, the synthesis methods making the types of CuNCs more varied are also summarized. Furthermore, mechanisms of fluorescence changes induced by HMIs are explained. After that, the relevant reports of CuNCs in several typical HMI detection are further listed. In addition, combined with the above content, the challenges and prospects of CuNCs in HMIs detection are also proposed.