Visible-light excited carbon dots with dual emission long-afterglow for temperature sensing and anti-counterfeiting

Long-afterglow luminescent materials has undergone extensive research in sensing and anti-counterfeiting. However, the complex preparation process, single luminescence with low quantum yields, potential biological toxicity and harsh application conditions limited the widespread use of these materials. In this work, 3-APBA CDs@MA was obtained by 3-aminophenylboronic acid, sulfuric acid and melamine via a one-pot hydrothermal process. The as-designed 3-APBA CDs@MA exhibit dual emission with quantum yields of 15.74% and lifetime of 1.39 s for thermally activated delayed fluorescence and 1.63 s for room temperature phosphorescence. The afterglow of carbon dots can be observed by the naked eye for about 24 s and 13 s after turning off the 365 nm UV lamp and visible light lamp, respectively. Furthermore, the as-obtained 3-APBA CDs@MA show potential for temperature sensing and advanced anti-counterfeiting.