m-Dinitrobenzene directed aggregation-induced emission enhancement of cysteine modified fluorescent copper nanoclusters

Abstract The sensing ability of l -cysteine modified fluorescent copper nanoclusters (Cys-CuNCs) was investigated in details with various nitro-aromatics. In addition to the reported sensing analyte i.e. picric acid (PA) that quenched the fluorescence of Cys-CuNCs, the presence of m -dinitrobenzene ( m -DNB) dramatically enhanced the fluorescence of Cys-CuNCs in aqueous medium (PBS buffer, pH = 9.0) among the other tested nitro-aromatics. The aggregation-induced emission enhancement of Cys-CuNCs in the presence of m -DNB was supported with DLS analysis. Under optimum conditions, this developed Cys-CuNCs exhibits a linear response in the concentrations range of 1.30 × 10 −6  M–9.90 × 10 −8  M with the limit of detection down to 1.3 × 10 −7  M for m -DNB.