Facile Synthesis of Multi-Emission Nitrogen/Boron Co-Doped Carbon Dots from Lignin for Anti-Counterfeiting Printing

Abstract

The transformation of lignin with natural aromatic structure into value-added carbon dots (CDs) achieves a win-win situation for low-cost production of novel nanomaterials and reasonable disposal of biomass waste. However, it remains challenging to produce multi-emission CDs from biomass for advanced applications. Herein, a green and facile approach to preparing multi-emission CDs from alkali lignin via N and B co-doping is developed. The obtained N and B co-doped CDs (NB-CDs) show multi-emission fluorescence centers at 346, 428 and 514 nm under different excitations. As the doping amount of N and B increases, the fluorescence emission band gradually shifts to 428 and 514 nm, while that at 346 nm decreases. The fluorescence mechanism is explored through the research of the structure, composition and optical performance of NB-CDs in combination with density functional theory (DFT) calculations. It demonstrates that the effect of doping with B-containing functional groups on the fluorescence emission behavior is multivariate, which may be the crucial contribution to the unique multi-emission fluorescence of CDs. The multi-emission NB-CDs with prominent stability are applied for multilevel anti-counterfeiting printing. It provides a promising direction for the sustainable and advanced application of biomass-derived CDs, and the theoretical results highlight a new insight into the deep understanding of the multi-emission fluorescence mechanism.

Red, yellow, green, and blue light-emitting highly crystallized graphene quantum dots derived from lignin: controllable syntheses and light-emitting diode applications

“…This double exponential decay curve consists of short-and long-lived components (τ 1 and τ 2 ), corresponding to the recombination processes of the core band (π-π*) and the edge band (n-π*), respectively. 28,29 From B-GQDs to R-GQDs, the percentage area of τ 1 decreases from 98.27% to 76.3% under 375 nm excitation (Table S5 †). This indicates that the core state of GQDs predominantly contributes to the fluorescence lifetime.…”

“…Among them, R-GQDs display the highest absorbance at the same mass concentration due to their optimal conjugated structures and functional groups. 29 To further investigate the band gap changes, the UV-vis absorption data were used to calculate the optical band gap values of each GQD using the Tauc relation equation (Fig. S6 †).…”

“…These peaks were ascribed to the conjugated ketone group (CvO), the stretching of CvC in the monomeric phenyl ring, and the ether bond, respectively. 19,29,42,43 However, in the FT-IR spectra of these four GQDs, peaks at 1700 cm −1 and 1336 cm −1 cannot be observed (Fig. S13 †), implying the occurrence of ester hydrolysis and ether bond cleavage during the preparation reaction.…”

Sintesis Tinta Printer Berfluoresensi Berbasis Carbon Quantum Dots Berbiaya Murah untuk Anti Pemalsuan Dokumen

“…Oleh karena itu, perlu dikembangkan CQDs yang dapat memancarkan emisi multi-warna, agar dokumen, label pindai yang dicetak tidak dapat dipalsukan. Material CQDs dapat mengemisikan multi-warna melalui doping heteroatom N, B, P dan O [17].…”

Synthesis, Characterization and Performance of Materials for a Sustainable Future

“…Carbon quantum dots (CDs), as emerging fluorescent materials, have achieved rapid development in optical anti-counterfeiting applications. Shen et al [ 24 ] developed an eco-friendly and simple two-step route to synthesize multi-emission CDs using alkali lignin (AL) and 3-aminophenylboronic acid as the precursor and dopant. According to structure, composition, optical properties and DFT calculations, the multi-emission fluorescence mechanism of NB-CDs was ascribed to the synergistic effect of the core state and the surface-defect state of O, N and B.…”