Ratiometric fluorescence detection of trace water in organic solvents based on aggregation-induced emission enhanced Cu nanoclusters

A fast, sensitive, and convenient dual-emission water detector was robustly fabricated. This detector was prepared with blue fluorescent carbon dots (CDs) and red fluorescent Cu nanoclusters (NCs), and showed two well-resolved and intensity-comparable fluorescence peaks under a single excitation wavelength. Moreover, it showed strong red fluorescence in organic solvent due to the aggregation-induced emission enhancement (AIEE) properties of the Cu NCs, but the red fluorescence was gradually quenched with an increasing amount of water, whereas the blue fluorescence remained constant. The differences in response result in a continuous fluorescence color change from red to blue that can be clearly observed by the naked eye. Thus, as-prepared Cu NC-based dual-emission nanomaterials can be used for ratiometric fluorescence detection of trace amounts of water in organic solvents by taking advantage of the water sensitivity of their fluorescence intensity ratios (red/blue) and their low detect limits (<0.02% v/v). These studies demonstrate that a novel and sensitive dual-emission ratiometric water detector has been found, which shows promise for application in environmental monitoring, food inspection, and life science.