Production and Patterning of Fluorescent Quantum Dots by Cryogenic Electron-Beam Writing

Abstract

Graphene quantum dots (GQDs) have emerged as a promising type of functional material with distinguished properties. Although tremendous effort was devoted to the preparation of GQDs, their applications are still limited due to a lack of methods for processing GQDs from synthesis to patterning smoothly. Here, we demonstrate that aromatic molecules, e.g., anisole, can be directly converted into GQD-containing nanostructures by cryogenic electron-beam writing. Such an electronbeam irradiation product exhibits evenly red fluorescence emission under laser excitation at 473 nm, and its photoluminescence intensity can be easily tuned with the electron-beam exposure dose. Experimental characterizations on the chemical composition of the product reveal that anisole undergoes a carbonization and further graphitization process during e-beam irradiation. With conformal coating of anisole, our approach can create arbitrary fluorescent patterns on both planar and curved surfaces for concealing information or anticounterfeiting applications. This study provides a one-step method for production and patterning of GQDs, facilitating their applications in highly integrated and compact optoelectronic devices.

Preparation of carbon dots-metal nanoparticles nanocomposites and their application in heterogeneous catalysis

“…After the polymer film on the substrate is selectively irradiated by an electron beam, the irradiated or non-irradiated areas are then removed with specific methods. Lu et al realized the patterning of GQDs by the pattern of GQDs lithography [86]. Firstly, a silicon substrate was fixed on the cryostage and cooled down to 120 K. Solid anisole was vapor-deposited onto the substrate.…”

Protein-based bioactive coatings: from nanoarchitectonics to applications

“…221 Furthermore, interactions between proteins and polyphenols, 222 like tannic acid, have been explored for various applications, including catalysis, fluorescence imaging, and cell targeting. Multilayered bioactive coatings comprising tannic acid and lysozyme have been tailored to enhance antioxidative, antibacterial, 223 and osteogenesis-promoting attributes, 224 with further investigations into cell adhesion and proliferation. 225 Layer-by-layer (LbL) films and capsules derived from proteins have been known for some time.…”

Advances in Structural Modifications and Properties of Graphene Quantum Dots for Biomedical Applications

“…Some of these methods are described below in detail with examples while emphasizing their advantages as well as limitations. Several methods such as electron beam lithography, chemical oxidation, , hydrothermal, , solvothermal, microwave-assisted, , green-chemistry, synthesis, laser ablation, plasma, chemical vapor deposition, and electrochemical , routes have been employed to synthesize the GQDs. Subsequently, this approach is low cost, uses abundant raw materials, and produces edge-functionalized and water-soluble GQDs.…”

“…Hence, the biodegradable plant waste materials are recycled into value-added products by this green-synthesis approach. For instance, the biomass materials like cellulose, citric acid, lignin, and waste sewage are used to produce hydrophilic GQDs by different routes. − A facile, scalable, and one-pot microwave-assisted green-synthesis route involved a microwave reaction of ethanolic extracts of Mangifera indica (mango) leaves and yielded high-quality red luminescent GQDs (Figure b) . Another sustainable strategy for the synthesis of GQDs from carbon-rich biochar (spent tea leaves) produced GQDs in ∼84% yield by pyrolysis and a microwave-assisted method .…”