Carbon dots: synthesis, formation mechanism, fluorescence origin and sensing applications

Abstract

We systematically summarize the recent progress in the green synthesis and formation mechanism of CDs with the hope to provide guidance for developing CDs with the concept of green chemistry. In addition, we discuss and organize the current opinions on the fluorescence origin of CDs and the latest progress of CDs in fluorescence sensing applications.

Flexible and Robust Electro‐Optically Responsive Films Based on Novel Silica/Oligoaniline/Carbon Dots Composite

“…[5][6][7][8] While these materials offer extraordinary properties, production scale manufacturing of devices based on many of these materials remains a chemistry and engineering challenge due to a variety of factors. [11][12][13][14][15][16] Oligoanilines, as model compounds of polyaniline, have garnered significant interest due to interesting and predictable electroactive properties and potential applications in anticorrosion, sensors, tissue engineering, and energy-related fields. We surmised it might be possible to create composite films with properties similar to organic electronic materials by decorating electroactive components with ortho silicates units, cast them on an ITO surface, and crosslink the ortho silicates hydrolytically.…”

“…[11][12][13] Generally, CDs are composed of inner sp 2 -hybridized carbon atoms, outer sp 3 -hybridized carbon atoms, and surface oxygen-containing functional groups such as amino, epoxy, ether, carbonyl, hydroxyl and carboxylic acid groups, thus making them possess excellent water solubility, easily tunable surface functionalization or subsequent labels with various chemical species. [11][12][13] Generally, CDs are composed of inner sp 2 -hybridized carbon atoms, outer sp 3 -hybridized carbon atoms, and surface oxygen-containing functional groups such as amino, epoxy, ether, carbonyl, hydroxyl and carboxylic acid groups, thus making them possess excellent water solubility, easily tunable surface functionalization or subsequent labels with various chemical species.…”

“…To these ends we chose a combination of oligoanilines (based on our previous work) [9,10] and carbon dots (chosen for a number of reasons highlighted below). [11][12][13][14][15][16] Oligoanilines, as model compounds of polyaniline, have garnered significant interest due to interesting and predictable electroactive properties and potential applications in anticorrosion, sensors, tissue engineering, and energy-related fields. [17][18][19][20][21] Introducing oligoanilines in a variety of polymeric architectures can endow them with attractive electroactivity and stimuli-responsiveness, while featuring superior solubility, processability, and tunability.…”

“…Carbon dots (CDs), as new emerging fluorescent carbonaceous nanomaterials, have likewise received significant research interest in recent years, related in large part to their advantages over metal-based quantum dots such as low toxicity, tunable fluorescence, improved water solubility and unique physicochemical properties. [11][12][13] Generally, CDs are composed of inner sp 2 -hybridized carbon atoms, outer sp 3 -hybridized carbon atoms, and surface oxygen-containing functional groups such as amino, epoxy, ether, carbonyl, hydroxyl and carboxylic acid groups, thus making them possess excellent water solubility, easily tunable surface functionalization or subsequent labels with various chemical species. [14][15][16] In view of the fluorescence and tunable surface characteristics of CDs, we surmised that a new hybrid material could be generated through covalent bonds between oligoanilines and CDs.…”

Manipulating the Optical Properties of Carbon Dots by Fine‐Tuning their Structural Features

“…[8] Current synthetic approaches to produce CDs include top-downa nd bottom-up methods, which usuallyg ive aggregated graphene-like layers of various size and al arge structurald iversity including sp 2 /sp 3 carbon networks and oxygen-rich functional groups in different ratios. [9] As ar esult, the PL quantum yields of CDs vary widely,f rom < 1t o9 5%, depending on the synthesis. Emissionst hat are dependent on and independent of excitation wavelength have also been As an ew class of sustainable carbonm aterial, "carbon dots" is an umbrella term covering many types of materials.…”