Electrochemistry and electrochemiluminescence study of blue luminescent carbon nanocrystals

Graphene quantum dot electrochemiluminescence increase by bio-generated H2O2 and its application in direct biosensing

In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GOx) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GOx can catalytically oxidize glucose and the direct electron transfer between the redox centre of GOx and the modified electrode also has been realized, which results in the bio-generated H₂O₂ for ECL signal increase in GQD and realizes the direct ECL detection of glucose. The signal-increase ECL biosensor enables glucose detection with high sensitivity reaching 5 × 10^-6 mol l^-1 in a wide linear range from 5 × 10^-6 to 1.5 × 10^-3 mol l^-1. Additionally, the fabrication process of such GQD-based ECL biosensor is also suitable to other biologically produced H₂O₂ system, suggesting the possible applications in the sensitive detection of other biologically important targets (e.g. small molecules, protein, DNA and so on).

Electrochemical Methods to Study Photoluminescent Carbon Nanodots: Preparation, Photoluminescence Mechanism and Sensing

With unique and tunable photoluminescence (PL) properties, carbon nanodots (CNDs) as a new class of optical tags have been extensively studied. Because of their merits of controllability and sensitivity to the surface of nanomaterials, electrochemical methods have already been adopted to study the intrinsic electronic structures of CNDs. In this review, we mainly deal with the electrochemical researches of CNDs, including preparation, PL mechanism, and biosensing.

Polyamine-functionalized carbon nanodots: a novel chemiluminescence probe for selective detection of iron(iii) ions

We firstly studied the chemiluminescence behavior of branched poly(ethylenimine)-functionalized carbon dots (BPEI-CDs).

The optoelectronic behaviour of carbon nanoparticles: evidence of the importance of the outer carbon shell

The particular properties of carbon nanoparticles (CNPs) have generated great interest in biomedicine, bioanalysis and optoelectronics. However, an association between the CNPs' physicochemical properties with their molecular and morphological characteristics is, even today, a topic of discussion. In this work, we use a simple method of synthesis with the ultimate aim of elucidating the structural nature of the obtained CNPs and its relationship with their well-known fluorescent properties. The sample is studied by high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), nuclear magnetic resonance (NMR), UV-visible and IR spectroscopy, electrochemistry and electrogenerated chemiluminescence (ECL). The results showed that the nanoparticles are constituted by a graphitic core surrounded by an amorphous layer, which seems to be significant in the determination of the optical and electronic properties observed in the system under study.

Chemiluminescence of carbon dots under strong alkaline solutions: a novel insight into carbon dot optical properties

We report the surprising chemiluminescence (CL) behavior of fluorescent carbon dots in the presence of a strong alkaline solution, such as NaOH or KOH. The CL intensity was dependent on the concentration of the base and carbon dots in a certain range. A possible CL mechanism was studied by UV-Vis, fluorescence, CL, FTIR, XPS and EPR spectroscopy. Radiative recombination of the injected electrons by "chemical reduction" of carbon dots with thermally excited generated holes was proposed, which sheds new light on the characteristics of carbon dots.

Fluorescence emission properties of C60 nanoparticles

Fluorescence properties of C60 nanoparticles produced by sonication in pyridine have been systematically investigated. The fluorescence emission of C60 is dependent on the particle size. A red shift of emission maximum from 424 to 468 nm originates from the average size increase caused by strong interaction among C60 molecules in nanoparticles. In addition, it is also confirmed that the emergence of broad fluorescence emission band in the 550-570 nm region is ascribed to C60 nanoparticles aggregation.

Interrogating near-infrared electrogenerated chemiluminescence of Au25(SC2H4Ph)18(+) clusters

The electrochemistry, near-infrared photoluminescence (NIR-PL) spectroscopy, and electrogenerated chemiluminescence (ECL) of Au(25)(SC(2)H(4)Ph)(18)(+)C(6)F(5)CO(2)(-) (Au(25)(+)) clusters were investigated. For the first time, NIR-ECL emission was observed in both annihilation and coreactant paths. Our newly developed spooling spectroscopy was employed during the ECL evolution and devolution processes along with explicit NIR-PL spectroscopy to elucidate light generation mechanisms. It was discovered that the electronic relaxation of the Au(25)(-) excited state to the ground state plays a key role in giving off ECL at 893 nm, while intermediate, strong, and weak NIR-PL emissions at 719/820, 857, and 1080 nm can be attributed to the excited states higher than the HOMO-LUMO gap, across the HOMO-LUMO gap, and of semi-rings, respectively.