Search results for "carbon nanodot"
showing 10 items of 20 documents
Enhancing carbon dots fluorescence via plasmonic resonance energy transfer
2022
Using plasmonic interactions to engineer optical properties at the nanoscale is an important challenge of current photonics. Here we establish a general strategy to enhance the orange emission of carbon dots by coupling them to gold nanoparticles through a polymeric spacer in solution. We exploit the overlap between the surface plasmon resonance of gold and the electronic transitions of carbon dots to achieve a fivefold increase of their fluorescence in the orange region, which is usually very weak. We demonstrate that this enhancement stems from an ultrafast resonance energy transfer from the coherent plasmonic state of the gold nanoantenna to the coupled carbon dot. Our study advances the…
Electron transfer between carbon dots and tetranuclear Dawson-derived sandwich polyanions
2022
Among the photocatalysts which could be used for converting solar energy, polyoxometalates are often regarded as ideal candidates because of their remarkable performances in photocatalytic water splitting and photodegradation of pollutants. Nonetheless, these polyanions are only capable of absorbing UV light, unless coupled to a visible-light photosensitizer. Carbon nanodots are especially promising for this purpose because of their strong visible-light absorption, photostability, non-toxicity, and very low production costs. In this work we demonstrate the possibility of coupling carbon dots to polyoxometalates with different structures, by a simple self-assembly approach based on electrost…
Carbon Nanodots as Functional Excipient to Develop Highly Stable and Smart PLGA Nanoparticles Useful in Cancer Theranostics
2020
Theranostic systems have attracted considerable attention for their multifunctional approach to cancer. Among these, carbon nanodots (CDs) emerged as luminescent nanomaterials due to their exceptional chemical properties, synthetic ease, biocompatibility, and for their photothermal and fluorescent properties useful in cancer photothermal therapy. However, premature renal excretion due to the small size of these particles limits their biomedical application. To overcome these limitations, here, hybrid poly(lactic-co-glycolic acid) (PLGA-CDs) nanoparticles with suitable size distribution and stability have been developed. CDs were decisive in the preparation of polymeric nanoparticles, not on…
Photobleaching and Recovery Kinetics of a Palette of Carbon Nanodots Probed by In Situ Optical Spectroscopy
2022
Carbon dots (CDs) are a family of fluorescent nanoparticles displaying a wide range of interesting properties, which make them attractive for potential applications in different fields like bioimaging, photocatalysis, and many others. However, despite many years of dedicated studies, wide variations exist in the literature concerning the reported photostability of CDs, and even the photoluminescence mechanism is still unclear. Furthermore, an increasing number of recent studies have highlighted the photobleaching (PB) of CDs under intense UV or visible light beams. PB phenomena need to be fully addressed to optimize practical uses of CDs and can also provide information on the fundamental m…
Shifting the Photoresponse of ZnO Nanowires into the Visible Spectral Range by Surface Functionalization with Tailor-Made Carbon Nanodots
2018
We report on the surface functionalization of ZnO nanowires (NWs) with specifically synthesized carbon nanodots (C-dots, CDs) that allows us to shift the photoresponse of the NWs far into the visib...
Photocycle of Excitons in Nitrogen-Rich Carbon Nanodots: Implications for Photocatalysis and Photovoltaics
2020
Nitrogen-rich carbon nanodots have emerged as promising nanomaterials for a wide range of applications where a highly emissive and photoactive material with low toxicity and cost-effectiveness is required. One of their hallmarks is indeed a bright, tunable fluorescence of excitonic nature. Disentangling the origin of their optical absorption and fluorescence properties and uncovering relaxation channels and interactions with solvents are some of the most debated issues in the field. Uncovering these aspects is essential for targeted applications, especially in the fields of photocatalysis but also photovoltaics and optoelectronics. Here, we present dedicated transient absorption measurement…
Disentangling size effects and spectral inhomogeneity in carbon nanodots by ultrafast dynamical hole-burning.
2018
Carbon nanodots (CDs) are a novel family of nanomaterials exhibiting unique optical properties. In particular, their bright and tunable fluorescence redefines the paradigm of carbon as a "black" material and is considered very appealing for many applications. While the field keeps growing, understanding CDs fundamental properties and relating them to their variable structures becomes more and more critical. Two crucial problems concern the effect of size on the electronic structure of CDs, and to what extent their optical properties are influenced by structural disorder. Furthermore, it remains largely unclear whether traditional concepts borrowed from the photo-physics of semiconductor qua…
Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response
2018
Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunable fluorescence, a marked sensitivity to the environment and a range of interesting photochemical properties. CDs are currently the subject of very intense research, motivated by their possible applications in many fields, including bioimaging, solar energy harvesting, nanosensing, light-emitting devices and photocatalyis. This review covers the latest advancements in the field of CDs, with a focus on the fundamental understanding of their key photophysica…
Carbon Nanodots for On Demand Chemophotothermal Therapy Combination to Elicit Necroptosis: Overcoming Apoptosis Resistance in Breast Cancer Cell Lines
2020
Background: Engineered luminescent carbon nanodots (CDs) are appealing nanomaterials for cancer image-guided photothermal therapy combining near infrared (NIR)&ndash
Temperature-Dependence of Solvent-Induced Stokes Shift and Fluorescence Tunability in Carbon Nanodots
2019
We carried out a cryogenic investigation on the optical properties of carbon dots, aiming to better understand their emission mechanism and the role of the solvent. The solvatochromic Stokes shift is quantified by a low temperature approach which allows freezing of the photo-excited state of carbon dots, preventing any solvation relaxation. Moreover, the reduction in temperature helps to identify the dynamical inhomogeneous contribution to the broadening of the emission band; therefore, disentangling the role of solvent from other types of broadening, such as the homogeneous and the static inhomogeneous contributions.