Solubility tuning of alkyl amine functionalized carbon quantum dots for selective detection of nitroexplosive. (5th June 2023)

• Record Type: Journal Article
• Authors: Mondal, Tapas Kumar; Kapuria, Arijit; Miah, Milon; Saha, Shyamal K.
• Is Part Of: Carbon. Volume 209(2023)
• Publication Date: 2023-06-05
• Subjects: Carbon quantum dots -- Alkyl amine functionalization -- Solid state luminescence -- Fluorescence quenching -- Colorimetric detection; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2023.03.047
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: The major issue of luminescent carbon quantum dots (CQDs) is the solubility in wide range of solvent and disappearance of luminescence behavior in its solid state due to aggregation caused quenching. To resolve this issue, in the present work, we have tuned the solubility of carbon quantum dots in different kinds of solvents through surface functionalization technique. Here, we have synthesized three sets of alkyl amine functionalized carbon quantum dots from citric acid and alkyl amine by solvothermal method. We have observed that the solubility of CQDs increases from aqueous medium to organic medium with increasing length of hydrophobic alkyl chains attached at the surface of CQDs. It is seen that n-butyl amine functionalized CQDs (C4 -CQD) are soluble in any type of solvents. Here we have also observed that the C4 -CQD shows aggregation induced emission instead of aggregation caused quenching in solid state and shows bright yellow luminescence color upon excitation. Besides this, we also report selective detection of both dinitroaniline (DNA) and dinitrophenol (DNP) using this C4 -CQD via fluorescence quenching and colorimetric methods. In organic medium both shows significant quenching with emission peak of carbon quantum dots is red shifted (∼30 nm) in presence of DNP whereas no significant peak shift is observed for DNA. CQDs containing paper strip shows yellow spot in presence of DNP but no such characteristic color is appeared after addition of DNA. Using these two techniques, we have selectively identified both DNA and DNP among other nitro compounds by our as-synthesized carbon dots. Graphical abstract: Image 1 Highlights: Solubility of carbon dots is tuned by alkyl amine functionalization. n-butyl amine functionalized carbon dots are soluble in any type of solvent (polar and non-polar). Alkyl amine functionalized carbon dots show yellow luminescence at solid state due to aggregation induced emission. Both dinitrophenol and dinitroaniline are selectively detected by fluorescence quenching and colorimetric methods.