Double-enhanced fluorescence of graphene quantum dots from cane molasses via metal and PEG modification for detecting metal ions and pigments

Cane Molasses Derived N-Doped Graphene Quantum Dots: Dynamic Quenching Synergistically Photoinduced Electron Transfer for the Instant Detection of Nitrofuran Antibiotics

“…Figure c–e,f–h shows the high-resolution spectra of C 1s, N 1s, and O 1s of GQDs and N-GQDs, respectively. The C 1s high-resolution XPS spectrum of GQDs (Figure c) shows four fitting peaks of 284.8, 285.33, 286.3, and 288.82 eV, corresponding to the C–C (sp 3 )/CC (sp 2 ), C–N, C–O–C, and O–CO bonds. − The high-resolution N 1s spectrum (Figure d) has two peaks at 399.87 and 401.69 eV, which are assigned to N–H and C–N, respectively. , In addition, the O 1s high-resolution spectrum of GQDs (Figure e) also shows two peaks at 532.36 and 533.56 eV, which belong to the C–O–H/C–O–C and CO bonds. , The high-resolution spectrum of C 1s from N-GQDs (Figure f) confirms the existence of four fitting peaks at 284.8, 285.65, 286.59, and 288.82 eV, corresponding to the C–C (sp 3 )/CC­(sp 2 ), C–N, C–O–C, and O–CO bonds. − The high-resolution N1s spectrum (Figure g) was fitted to show two peaks at 400.32 and 401.71 eV, belonging to N–H and C–N, respectively. , The O 1s high-resolution spectrum of N-GQDs (Figure h) also reflects the presence of C–O–H/C–O–C (532.17 eV) and CO (533.45 eV). − ,, …”

“…Figure 3c− 30−32 The highresolution N 1s spectrum (Figure 3d) has two peaks at 399.87 and 401.69 eV, which are assigned to N−H and C−N, respectively. 32,35 In addition, the O 1s high-resolution spectrum of GQDs (Figure 3e) also shows two peaks at 532. 36 30−32 The high-resolution N1s spectrum (Figure 3g) was fitted to show two peaks at 400.32 and 401.71 eV, belonging to N−H and C−N, respectively.…”

“…36 30−32 The high-resolution N1s spectrum (Figure 3g) was fitted to show two peaks at 400.32 and 401.71 eV, belonging to N−H and C−N, respectively. 32,35 The O 1s high-resolution spectrum of N-GQDs (Figure 3h) also reflects the presence of C−O−H/C−O−C (532.17 eV) and C�O (533.45 eV). [30][31][32]35,36 In order to investigate the optical property of GQDs and N-GQDs, UV−vis absorption spectroscopy, 2D fluorescence, 3D fluorescence, fluorescence lifetime, and QY were performed and tested.…”

“…32,35 The O 1s high-resolution spectrum of N-GQDs (Figure 3h) also reflects the presence of C−O−H/C−O−C (532.17 eV) and C�O (533.45 eV). [30][31][32]35,36 In order to investigate the optical property of GQDs and N-GQDs, UV−vis absorption spectroscopy, 2D fluorescence, 3D fluorescence, fluorescence lifetime, and QY were performed and tested. Figure 4a shows the UV−vis absorption spectra of GQDs and N-GQDs.…”

“…The absolute value of the Zeta potential of N-GQDs is significantly greater than that of GQDs, indicating that N-GQDs have better stability than GQDs. 27,35 Figure 5b shows the fluorescence intensity change of GQDs and N-GQDs within 60 days, the less change indicating that N-GQDs is more stable than GQDs. Figure 5c is the fluorescence intensity change of GQDs and N-GQDs in the presence of different NaCl concentrations.…”