Tb3+ tuning AIE self-assembly of copper nanoclusters for sensitively sensing trace fluoride ions

The Tb 3+ triggered self-assembly of GSH-CuNCs caused over 260-fold FL enhancement and 14-fold quantum yield increase, and this finding results in a new sensitive and selective assay for trace fluoride ions in aqueous media. • Tb 3+ caused self-assembly of CuNCs to produce aggregated ones with 260-fold FL rise. • Relative to disperse CuNCs, the Tb 3+ -CuNCs show 14-fold enhancement in QY. • Compared to CuNCs, the Tb 3+ -CuNCs show better stability and high salt stability. • A highly sensitive and selective FL sensor was developed for F- ions. • The method was successfully applied to determine F − in real samples. Tb 3+ ions induce highly emissive copper nanoclusters (CuNCs) from weakly luminescent glutathione (GSH)-CuNCs driven by aggregation induced emission (AIE) mediated self-assemblies. The latter were fabricated via a one-step route utilizing GSH as both a reductant and a stabilizing agent. Complexation of Tb 3+ with the carboxyl groups of GSH on the surface of GSH-CuNCs reduces nonradiative relation of the excited state(s) by restricting the intramolecular rotation-vibrational motion. This allows the formation of the highly red emissive Tb 3+ -CuNCs with over 260-fold emission increase. Moreover, the Tb 3+ -CuNCs exhibit increased long-term storage stability and a 14-fold increase in quantum yield relative to the GSH-CuNCs. The intense red fluorescence from Tb(III)-CuNCs is quenched by F − ions because of strong Tb 3+ coordination with F − . On this basis, a new assay was constructed to selectively and sensitively detect F − ions. The limit of detection (LOD) for F − is 10 nM, which is lower than that stipulated by the World Health Organization (63.16 μM in drinking water). The Tb(III)-CuNCs-based fluorescence assay was applied to determine F − in real samples with satisfactory result.