Carbon Dots and Their Polymeric Nanocomposites: Insight into Their Synthesis, Photoluminescence Mechanisms, and Recent Trends in Sensing Applications

Abstract

Carbon dots (CDs), a novel class of carbon-based nanoparticles, have received a lot of interest recently due to their exceptional mechanical, chemical, and fluorescent properties, as well as their excellent photostability and biocompatibility. CDs' emission properties have already found a variety of potential applications, in which bioimaging and sensing are major highlights. It is widely acknowledged that CDs' fluorescence and surface conditions are closely linked. However, due to the structural complexity of CDs, the specific underlying process of their fluorescence is uncertain and yet to be explained. Because of their low toxicity, robust and wide optical absorption, high chemical stability, rapid transfer characteristics, and ease of modification, CDs have been recognized as promising carbon nanomaterials for a variety of sensing applications. Thus, following such outstanding properties of CDs, they have been mixed and imprinted onto different polymeric components to achieve a highly efficient nanocomposite with improved functional groups and properties. Here, in this review, various approaches and techniques for the preparation of polymer/CDs nanocomposites have been elaborated along with the individual characteristics of CDs. CDs/ polymer nanocomposites recently have been highly demanded for sensor applications. The insights from this review are detailed sensor applications of polymer/CDs nanocomposites especially for detection of different chemical and biological analytes such as metal ions, small organic molecules, and several contaminants.

Carbon Dot-Decorated Polystyrene Microspheres for Whispering-Gallery Mode Biosensing

“…These bands, with peaks at 548 nm and 583 nm, are only faintly discernible. The fluorescence spectrum of carbon dots changes when they are embedded into polymer microspheres (Figure 2a) from the solution, which is explained by characteristic mechanisms such as surface passivation, aggregation effects, confinement effects, charge transfer, and/or polarity changes (Figure 2b) [36][37][38][39]. Meanwhile, the fluorescence spectra of CDs exhibit excitation-dependent emission due to the coexistence of multiple emissive centers within carbon dots.…”

New 3D Vortex Microfluidic System Tested for Magnetic Core-Shell Fe3O4-SA Nanoparticle Synthesis

“…These nanoparticles play a crucial role in medical fields such as targeted drug delivery systems, bioimaging, biosensing, and cancer hyperthermia treatment [ 7 , 8 , 9 , 10 , 11 ]. The technology sector benefits from their utility in data storage, sensing devices, and catalysis [ 12 , 13 , 14 , 15 , 16 ].…”