Nitrogen-Doped Carbon Quantum Dots from Poly(ethyleneimine) for Optical Dual-Mode Determination of Cu2+ and l-Cysteine and Their Logic Gate Operation

• DOI: 10.1021/acsami.0c12750
• Publication Date: 2020-09-21T18:54:41Z
• Authors: Xuerui Liu; Shengxiao Zhang; Hui Xu; Ruru Wang; Lina Dong; Shanmin Gao; Boyang Tang; Weina Fang; Faju Hou; Linlin Zhong; Ali Aldalbahi
• Keywords: Quantum yield; Absorbance

In this work, nitrogen-doped carbon quantum dots from poly(ethyleneimine) (PQDs) were synthesized by a low-cost and facile one-step hydrothermal method without other reagents. A yield (QY) of up to 23.2% with maximum emission at 460 nm under an excitation wavelength 340 was ascribed the high nitrogen doping (20.59%). The PQDs selectively form blue complex Cu2+ accompanied strong quenching fluorescence emission. Meanwhile, PQD-Cu2+ exhibited selective recovery color disappearance on exposure l-cysteine (Cys). electron transfer amino or oxygen groups leads quenching, chromogenic reaction cuprammonium results in change. affinity between Cys causes detachment surface PQDs, so solution disappears recovers. Under optimized condition, proposed sensor applied detect linear range 0–280 μM. detection limit 4.75 μM is achieved using spectroscopy 4.74 monitoring absorbance variation 272 nm. For detection, 0–800 limits 28.11 (fluorescence determination) 19.74 (peak shift determination nm) obtained. system exhibits distinguishable responses biothiols such as l-glutathione (GSH) dl-homocysteine (Hcy). Based multimode signals, "AND" logic gate constructed successfully. Interestingly, besides Cu2+, Fe3+ can also quench PQD-Fe3+ superior selectivity for detection. Most importantly, assay not only simple, cheap, stable but suitable detecting some real samples.