Photoexcited State Properties of Poly(9-vinylcarbazole)-Functionalized Carbon Dots in Solution versus in Nanocomposite Films: Implications for Solid-State Optoelectronic Devices

Abstract

Carbon dots (CDots) are small carbon nanoparticles with effective surface passivation accomplished mostly via organic functionalization. In this study, the largely amorphous carbon nanoparticles were copolymerized with N-vinylcarbazole in microwave-assisted radical reactions. The copolymers thus formed are structurally equivalent to the individual carbon nanoparticles each surface-functionalized by multiple poly(N-vinylcarbazole) (PVK) segments, thus denoted as PVK-CDots. Their electronic transitions and photoexcited state properties, including especially the characteristic excitation wavelength dependencies of fluorescence parameters, were found to be essentially the same as those commonly observed in CDots of small organic molecules for surface functionalization. The PVK-CDots were dispersed in neat PVK for polymeric nanocomposite films free from any other foreign materials. The optical absorptions and fluorescence emission properties of PVK-CDots in the solid-state film matrix environment were found to be little changed from those in solution. The significance of the findings and implications to various uses of these nanomaterials in optoelectronics and related fields are highlighted and discussed.

Carbon Dots: Classically Defined versus Organic Hybrids on Shared Properties, Divergences, and Myths

“…In fact, one may also argue that these copolymers can be viewed as CDots–polymer composites or hybrids. [ 39 ] As to be discussed below, similarly composite‐like sample structure or configuration may be found in the dot samples produced by the thermal carbonization method with right “one‐pot” processing conditions, which are therefore more appropriately considered as “nanocarbon/organic hybrids” (Figure 1) [ 40 ] or simply abbreviated as the “hybrids” in relevant descriptions in this article.…”

“…[37] The ability for small carbon nanoparticles to accept additions of organic radicals is also reflected by their observed ready participation in radical copolymerization reactions with common vinyl molecules such as vinyl acetate and 9-vinylcarbazole (Figure 2, lower). [38,39] The resulting copolymers are essentially polymer-functionalized small carbon nanoparticles, which are in chemical structure and sample configuration equivalent to polymer-attached CDots. In fact, one may also argue that these copolymers can be viewed as CDots-polymer composites or hybrids.…”

Carbon Dot as Visible-Light Photoredox Catalysts for a Myriad of Organic Transformations

“…For a long time, carbonaceous materials have played an important role in organic reactions. Charcoal and carbon black have been widely used as a catalytic support for different metal catalysts. , Since their discovery, carbon nanotubes and graphene have also played a pivotal role in acting as a platform in the fabrication of hybrid catalysts with semiconducting and noble metals. , The carbon dot is the newest member of the nanocarbon family and they are endowed with excellent optical properties and chemical robustness along with the added advantage of easy and cheap synthetic protocols. − Due to these advantageous properties, they have found utility in numerous fields starting from sensing toxic materials and biologically important molecules to optoelectronics and biomedical applications. − However, the use of carbon dots as a catalyst in different organic transformations has been relatively uncharted territory. A few reports on the use of carbon dots as a carbon catalyst in alcohol oxidation, aldol condensation, and cyclohexane oxidation are present in the literature , which are simple oxidation reactions.…”

Portable and non-invasive fluorescent thin films from photocatalytically active carbon dots for selective and trace-level detection of picric acid

“…This helps to make the sensor portable and reusable, enabling fast and sensitive on-site detection of pollutants. [43][44][45] Many polymeric platforms have been reported to form a film-based fluorescent platform for detecting potential pollutants by incorporating various PL sensing probes. Howsoever, most of the FL polymeric sensor strips or films reported so far [46][47][48] lack the combined merits of a simple fabrication procedure, high LOD with good selectivity, portability, less toxicity, least photo bleachability and multicycle detection ability.…”