Nanoarchitectonics of Cu-derived bright carbon dots towards Cr (VI) and tetracycline hydrochloride detection

Metal element doping often can improve the photoluminescence (PL) of carbon dots (CDs). In this paper, blue and green emitting CDs (BCDs and GCDs) were synthesized by using phenylenediamine as the carbon and nitrogen sources. Cu-doped CDs (Cu-CDs) were fabricated by using copper acetylacetone as a precursor. The PL peak wavelengths of sample Cu-doped blue CDs (Cu-BCDs) and green CDs (Cu-GCDs) were 450 and 543 nm, respectively. The full width at half maximum of PL spectra were 67.31 and 93.13 nm, the PL quantum yields (PLQYs) were 13.6 and 38.7 %, and the average fluorescence lifetimes were 4.34 and 20.97 ns, respectively. The PL intensity of the Cu-CDs samples was enhanced with the photostability, and thermal stability test results showed that the Cu-CDs samples also had excellent stability. The Cu-BCDs and Cu-GCDs were employed in the field of sensing applications due to their excellent selectivity towards Cr (VI) and tetracycline hydrochloride (TC) detection. The detection limits for Cr (VI) and TC using Cu-BCDs were 0.34 and 0.86 μM, while Cu-GCDs showed detection limits of 0.47 and 0.50 μM, respectively, demonstrating the broad application prospect for Cu-CDs in sensing applications.