Introduction of Hybrid Nanomaterials based on Nanocarbons
Introduction of Defective Nanocarbons
- Graphene Oxide (GO)
- Carbon Nanoparticles (CDs)
These hybrid nanomaterials have high efficiency in various applications such as bioimaging, therapy, photocatalyst, organic catalyst and electrocatalyst, and photovoltaic devices. Therefore, the remarkable properties of CDs have the promising applications such as bioimaging, drug delivery, sensor, photocatalyst and photovoltaic devices.38 However, although CDs are the promising nanocarbons with unique properties, it is still challenging to apply for new application due to the undefined structure of many synthetic methods and carbon sources.
Development of Hybrid Materials Based on Nanocarbons
- Hybrid Nanomaterials based on GO
- Hybrid Nanomaterials based on CDs
Reprinted with permission from ref. 41. a) Photograph of an aqueous dispersion (0.1 mg mL-1) of reduced graphene oxide-methylene green (left) and reduced graphene oxide (right). Reprinted with permission from ref. 49. c) Illustration of the preparation process for carbon nanoparticles/graphene oxide doped with boron and nitrogen.
Application of Hybrid Materials based on Nanocarbons
- Bio Application
- Energy Application
Reprinted with permission from ref. 54. a) Timeline showing recent progress and future prospects regarding the applications of carbon nanoparticles. Reprinted with permission from ref. 55. b) Internal quantum efficiency of PTB7:PC71BM-based PSCs with Ag-carbon nanoparticles.
Overview of Thesis
Nitrogen-doped graphene oxide quantum dots as photocatalysts for total water splitting under visible light illumination. Boron-nitrogen-doped graphene quantum dots/graphene hybrid nanosheets as efficient electrocatalysts for oxygen reduction.
Hybrid Gold Nanoparticle-Graphene Oxide Nanosheets and Their
Introduction
- Hybrid Nanomaterials based on GO
- Experimental
- References
An aqueous 4-dimethylaminopyridine (DMAP) solution (0.10 M, 1.0 mL) was added to aliquots (1.0 mL) of the as-prepared nanoparticle mixtures. Hybrid gold nanoparticle-reduced graphene oxide nanosheets as active catalysts for highly efficient reduction of nitroarenes.
Hybrid Gold Nanoparticle-Graphene Oxide Nanosheets as Active Catalysts
- Abstract
- Introduction
- Experimental
- Preparation of Hybrid gold nanoparticles (Au)–GO Nanocomposites
- Catalytic Reduction of 4-Nitrophenol by Hybrid Au–GO
- Characterizations
- Results and Discussion
- Conclusion
- References
The control experiments further elucidated the reaction mechanism of the hybrid Au-GO catalyst for the reduction of nitroarenes. We further investigated the catalytic activity of hybrid Au-GO for the reduction of other nitroarene analogues (Table 2.2.1).
Graphene Multilayer Supported Gold Nanoparticles for Efficient
- Abstract
- Introduction
- Experimental
- Layer-by-Layer Assembly of (Au/GO) n Multilayer Film
- Electrocatalytic Characterizations
- Characterizations
- Results and Discussion
- Conclusion
- References
Schematic representation of the possible mechanism of electrocatalytic activity of (Au/GO)n towards methanol oxidation depending on the number of bilayers (BL). Loading capacity of ZnPc on CD-PEG-FA, calculated from standard curve e. Schematic illustration of preparation of carbon nanoparticles (CD) from α-cyclodextrin and targeted photodynamic therapy with folic acid-functionalized carbon nanoparticles loaded with zinc phthalocyanine (CD-PEG-FA/ZnPc). a) UV-vis absorption spectra of CD, CD-PEG and CD-PEG-FA.
Functional groups of CDs and Ag-CD NPs were analyzed by XPS (K-alpha, Thermo Fisher) and FT-IR (Varian, Cray 660). Electrons photoexcited from CD reduce Ag+ ions in Ag NPs on the CD surface to provide heterodimeric Ag-CD NPs. Moreover, the crystalline phase of Ag-CD NPs was verified by XRD spectra (Figure 3.3.12).
The structure of CDs was analyzed by XPS (K-alpha, Thermo Fisher) and FT-IR (Varian, Cray 660). The morphology and size of CDs were measured using TEM (JEOL JEM-2100, accelerating voltage 200 kV). CNS structure was analyzed by XPS (K-alpha, Thermo Fisher) and FT-IR (Varian, Cray 660).
Hybrid Nanomaterials based on Carbon Nanoparticles
Introduction
The unique properties of carbon nanoparticles (CDs), such as high optical properties, water solubility, and electron transfer ability, facilitate applications for biological imaging, photovoltaic devices, and photocatalysts. Therefore, efficient CD-based hybrid nanomaterials are developed in Chapter 3, which not only have high PL intensity and cancer cell targeting ability in CDs, but also controllable and homogeneous morphology in metallic CDs. First, polymer passivated CDs are developed for high biocompatibility, non-toxicity and high PL intensity on the CDs.
Also, additional functionalization of targeted molecules in CD increases the efficacy in bioimaging and photodynamic therapy. Due to the abundant oxygen groups and electron transfer behavior of CDs, the Ag-CD heterodimeric structure is synthesized.
Highly Biocompatible Carbon Nanoparticles for Simultaneous Bioimaging
- Abstract
- Introduction
- Experimental
- Preparation of CDs
- Surface Passivation of CDs with Poly(ethylene glycol) and Folic acid
- Synthesis of Zinc Phthalocyanine loaded on CD-PEG-FA
- Characterizations
- Photoluminescence Lifetime Measurement
- Bioimaging and Photodynamic Therapy In vitro
- Bioimaging and Photodynamic Therapy In vivo
- Results and Discussion
- Conclusion
- References
The UV-vis absorbance of ZnPc was about 60 μg of ZnPc per milligram of CD-PEG-FA. To investigate the photodynamic effect, CD-PEG-FA/ZnPc (50 µg/ml) with a serum-free medium was treated with HeLa cells/well), which were preincubated in a 12-well plate for 24 h. Rats were divided into 6 groups: (1) saline; (2) CD-PEG-FA without irradiation; (3) CD-PEG-FA with irradiation; (4) CD-PEG/ZnPc without irradiation; (5) irradiated CD-PEG/ZnPc; (6) CD-PEG-FA/ZnPc without irradiation; (7) CD-PEG-FA/ZnPc by irradiation.
Furthermore, CD-PEG and CD-PEG-FA showed bright blue emission under UV irradiation (inset in Figure 3.2.2a). After characterizing the chemically functionalized CDs, ZnPc was loaded onto CD-PEG-FA by π-π stacking interactions. CD-PEG-FA bearing ZnPc (CD-PEG-FA/ZnPc) exhibited red-shifted absorption peaks at 607 and 689 nm originated from ZnPc and strongly quenched fluorescence of ZnPc, indicating the successful loading of ZnPc (Figure The characteristic fluorescence spectrum) and the QY of CD-PEG-FA also did not change when loaded with ZnPc (6 wt% of ZnPc/CD-PEG-FA).
Inset shows the CD-PEG-FA suspension (left) under room light and (right) UV illumination at 365 nm. -mode AFM images of (a) CD, (b) CD-PEG and (c) CD-PEG-FA with corresponding line scan profiles. a) UV-vis absorbance spectra of (red) CD-PEG-FA, (black) CD-PEG-FA/ZnPc and (blue) free ZnPc. Bright field and fluorescence images of HeLa cells treated with CD-PEG-FA/ZnPc (50 μg/ml) for 12 h.
Interface Controlled Synthesis of Heterodimeric Silver–Carbon
- Abstract
- Introduction
- Experimental
- Preparation of CDs
- Synthesis of Heterodimeric silver-CD Hybrid Nanomaterials
- Time-Correlated Single-Photon Counting Characterization
- Characterizations
- Finite-Difference Time-Domain Calculations
- Results and Discussion
- Conclusion
- References
Decomposed high-resolution XPS spectra of the C 1s peak of (a) CDChi and (b) Ag-CDChi, and (c) chemical compositions of CDChi and Ag-CDChi. Decomposed high-resolution XPS spectra of the C 1s peak of (a) CDAlg and (b) Ag-CDAlg and (c) chemical compositions of CDAlg and Ag-CDAlg. We found that the concentration of HCl added during CD formation is a critical parameter in controlling the size and interface of Ag-CDs.
The series of TEM images shown in Figure 3.3.13a and 3.3.13b show that increasing the concentration of HCl increases the size of the CDs. In addition, the size of Ag NPs increased with increasing HCl concentration in both CDs. This opposite trend in the solubility of the two polysaccharides may lead to differences in the synthesis of CDs during microwave carbonation.
The effect of the HCl additive on tuning the nanoscale interface of the Ag-CD NPs. a, b) Representative TEM images of (a) Ag-CDChi NPs and (b) Ag-CDAlg NPs prepared with different amounts of 1 M HCl additive, as shown in the figure. The temporal evolution of the PL of BN-CD was additionally investigated by time-resolved spectral measurements with picosecond accuracy (Table 4.2.7). Both N-CD and BN-CD have a longest lifetime component of 15 ns, which is attributed to the fluorescence lifetime of the core π-conjugated domains in CDs.
Origin of Photoluminescence of Nanocarbons
Introduction
- Origin of high photoluminescence of carbon nanoparticles
- Solvatochromic carbon nanosheets
- References
Carbon nanoparticles (CDs) have excellent photoluminescence (PL) properties, compared to other nanocarbons such as graphene oxide or fullerene. Many attempts have been made to synthesize high yield of PL from CDs through the modification of intrinsic and extrinsic states.1 In addition, PL mechanisms from CDs have been proposed due to the quantum confinement effect, different degrees of sp conjugation, surface states and surface defects . .2 However, the origin of PL of CDs is still controversial and debatable, because the different structure of CDs synthesized from different synthetic methods and carbon sources interrupt the PL mechanism of CDs to interpret the PL mechanism.3 Moreover, it is role model to explain the high PL behavior of CDs CDs have not yet been developed. Based on this new material, the origin of the high PL of CDs is elucidated by structural analysis, time-resolved emission spectroscopy, and density functional theory calculations, resulting in a graphitic structure and reduced surface traps of CDs.
In addition to the synthesis of high PL intensity from carbon nanomaterials, the tunable emission of carbon nanomaterials has been developed for a wide range of applications. Different carbonization conditions, controlled moral ratios of carbon sources, and surface modification with small or large molecules induce the tunable PL behavior of carbon nanomaterials from blue to red in UV or visible light.4-7 In particular, the surface state of carbon nanomaterials is mainly affected at the emission wavelength. In addition to these various synthetic methods, external stimuli also influence the PL behavior of carbon nanomaterials.
Some examples of graphene oxide and CDs have been reported with these properties; however, the emission range is very narrow from blue to green.8,9 Furthermore, no emission shift was observed in visible light. Mechanism of photoluminescence in carbon dots (graphene quantum dots, carbon nanodots and polymer dots): current status and future perspective. Red, green, and blue luminescence from carbon dots: full-color emission tuning and multicolor cellular imaging.
Integrative Approach toward Uncovering the Origin of Photoluminescence in
- Abstract
- Introduction
- Experimental
- Preparation of CDs
- Characterizations
- Photoluminescence Quantum Yield Measurement
- Time-Resolved Fluorescence Characterization
- Computational Method
- Single Molecule Microscopy
- Results and Discussion
- Conclusion
- References
Interestingly, the emission spectra of BN-CD showed excitation-independent behavior, while those of N-CD showed excitation dependence. Excitation and emission contour plots of (c) N-CD and (d) BN-CD. a) PL spectra of N-CD and BN-CD powder. According to EA and XPS, the main components of N-CD and BN-CD are C, N and O.
In the high-resolution C1s spectrum, BN-CD and N-CD showed different fractions of carbon-related bonding with N and O species. The different nitrogen contents in N-CD and BN-CD indicate that graphitic-N plays an important role in enhancing PL in CDs. Chemical structures of N-CD and BN-CD. a) FT-IR spectra and (b) XPS survey spectra of N-CD and BN-CD.
We investigated the ultrafast relaxation dynamics of CDs by measuring the emission lifetimes of BN-CD and N-CD. In addition, the B-OH located next to the graphitic-N acts similarly to the carbonyl group, which affects the PL properties of BN-CD. -molecular spectroscopy of N-CD and BN-CD. a,b) Time-dependent photoluminescence traces of (a) one N-CD and (b) one BN-CD with one-step photobleaching.
Shape-Tunable Solvatochromic Carbon Nanosheets
- Introduction
- Experimental
- Preparation of Solvatochromic Carbon Nanosheets
- Characterizations
- Results and Discussion
- Conclusion
- References
