Luminescent Wearable Sensor on Anions from Cotton Fabric Grafted with Cu-In-Zn-S Colloidal Quantum Dots

Negatively charged molecules and anions are widely present in the natural environment and can pose a threat to aquatic life, affecting their survival and reproduction. As the understanding of the hazards of negatively charged molecules and ions deepens, the need for real-time monitoring governs the development of highly sensitive and convenient sensing materials. Here, highly luminescent Zn-Cu-In-S core-shell colloidal quantum dots were grafted onto cotton fabric to produce a fluorescence cotton fabric (FCF) optical sensor demonstrating photoluminescence response to the presence of several anions in water, such as phosphate (PO₄^3-), hydroxide (OH^-), fluoride (F^-), chloride (Cl^-), or bromide (Br^-). After contact with water solutions containing these anions, PL output from FCF remarkably decreases, with specific functional dependence on the concentration of the selected anions. The fluorescent fabric sensing material is easy to operate, achieving real-time detection of negatively charged groups and showing great potential for application in environmental monitoring.