High luminescent N,S,P co-doped carbon dots for the fluorescence sensing of extreme acidity and folic acid

Abstract

Carbon dots have been popular luminescent materials because of their excellent fluorescence properties, but the low quantum yield limits their application. Heteroatom doping is a more convenient and popular approach...

Nitrogen-doped carbon quantum dots for fluorescence sensing, anti-counterfeiting and logic gate operations

“…The peak at ∼3477 cm −1 corresponds to the stretching vibration of O–H/N–H and the peak at ∼1162 cm −1 represents the tensile vibration of C–N. 20,36 Furthermore, the peak at ∼1660 cm −1 confirms the presence of CO, the peak at ∼1357 cm −1 corresponds to the CC vibration of sp 2 hybridization, and the peak at ∼1080 cm −1 corresponds to the stretching vibration of C–O. Additionally, the peak at ∼1581 cm −1 indicates the presence of an NH 2 group, and the peak that appears at ∼2827 cm −1 belongs to the tensile vibration of C–H.…”

“…Third, there are electron-donating substituent groups on the aromatic ring, which can facilitate charge transfer and reduce non-radiative decay pathways, thus increasing the QY. Therefore, methods to improve the QY of CQDs include surface passivation with electron donating groups, 19 heteroatom doping, 20,21 constructing large π systems, 22 and using molecules with sp 2 -conjugation domains as raw materials. 23 For example, nitrogen, phosphorus co-doped carbon quantum dots (N,P-CQDs) derived from beer were successfully synthesized, achieving a high QY of 21.7%.…”