Multi-color luminescent materials with potential applications in water detection based on 3-propyltriethoxysilane-modified Ag⁺-exchanged zeolites

Silver clusters encased within zeolites (Ag-zeolites) are preferred by researchers due to their remarkable luminescent characteristics. Nonetheless, developing luminescent silver-loaded zeolites via simple and efficient routes remains challenging. In this work, we have studied the luminescence properties of Ag-zeolites after surface modification by APTES. An interesting luminescent material based on 3-propyltriethoxysilane-modified Ag⁺-exchanged zeolite Y, with three luminescence centers at 470 nm, 525 nm, and 617 nm at various excitation wavelengths, was obtained. The surface modification caused an intense red emission, attributed to the production of silver nanoclusters with high nuclearity. The red luminescence was highly sensitive to trace water, demonstrating a linear correlation with water concentrations ranging from 0.02% to 0.06% v/v with a linear relationship R² = 0.99. The significant ratiometric luminescence response produced by water also caused a distinct hypochromatic shift in the emitting color, which could be easily observed by the naked eye. With high sensitivity, simple fabrication and real-time detection capabilities, this sensor will have practical applications in industrial water analysis.