Smartphone-Based Fluorescence Detection of Al3+ and H2O Based on the Use of Dual-Emission Biomass Carbon Dots

Carbon dots (CDs) have great application potential due to superior chemical and optical properties. In this work, a class of biomass-based carbon dots (BD-CDs) with multifunctionalities were synthesized by solvothermal treatment of the leaves of Cinnamomum plants. The BD-CDs can respond to Al3+ and H2O by distinctive emission wavelength at 470 and 670 nm under a single excitation. The emission at 470 nm is significantly enhanced by Al3+, and the fluorescence at 670 nm is quenched in the presence of H2O. A smartphone-based portable detection platform was developed for online analysis of Al3+ and H2O content. The BD-CDs based fluorescence sensing system and the detection platform showed excellent performance in the analysis of tap water and alcoholic drink samples, demonstrating great potential for application in food safety and environmental monitoring.