Environment‐Sensitive Carbon Dots Derived from Naphthalenediol for Solvent Polarity Indicator and Anti‐Counterfeiting

Abstract

Herein, a novel type of environment-sensitive carbon dots (ES-CDs) has been synthesized via ethanothermal reaction using 1,6-naphthalenediol as a carbon source and sulfuric acid as a catalyst. The morphology and structure of ES-CDs are characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectra (XPS). ES-CDs exhibit green and excitation wavelength independent emission in different solvents. Using the optical response of ES-CDs towards acetone-water binary mixtures with different composition, the sensitive detection of solvent polarity is realized based on the inner filter effect (IFE). The inkjet printed patterns of ES-CDs show a blue-to-green conversion as exposure to external vapor from hydrogen chloride to ammonia, and enable information to hide assisting with a laser direct writing. We believe that the environment-sensitive carbon dots developed in this study are potential candidates for solvent sensing and fluorescence anti-counterfeiting.

Turning Waste into Treasure: Multicolor Carbon Dots Synthesized from Waste Leather Scrap and their Application in Anti-Counterfeiting

“…Based on what is mentioned above, it can easily concluded that the reason for the multicolor CDs may be the size effect. The phenomenon is also verified by the report of Yang et al 13 Figure 2d−f exhibits the corresponding HRTEM images of the CDs, which obviously possess fringe spacings (0.235, 0.240, 0.254 nm) fitting with the (100) lattice distance of graphite carbon. 47,48 This implies that WLS occupied an important position because of its high carbon content of 42.29%.…”

“…6−8 With these advantages, CDs have found wide applications, 9 including living cells, 10 heavy metal indicators, 11 latent fingerprint detection, 12 and especially anti-counterfeiting. 12,13 The preparation method of CDs is one of the research hotspots. In recent years, various raw materials have been used to prepare CDs, such as non-biomass materials, including citric acid, 14−16 pyromellitic acid, 17 1,2,4,5-benzenetetramine tetrahydrochloride, 18 triethanolamine, 19 dopamine, 20 etc.…”

“…To solve the above problems, many scholars have turned their attention to carbon dots (CDs) in the past decades due to their easy modification, tunable photoluminescence (PL), good biocompatibility, high photostability, and facile synthesis process. − With these advantages, CDs have found wide applications, including living cells, heavy metal indicators, latent fingerprint detection, and especially anti-counterfeiting. , The preparation method of CDs is one of the research hotspots. In recent years, various raw materials have been used to prepare CDs, such as non-biomass materials, including citric acid, − pyromellitic acid, 1,2,4,5-benzenetetramine tetrahydrochloride, triethanolamine, dopamine, etc.…”