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Quantum Yield Enhancement in Graphene Quantum Dots via Esterification with Benzyl Alcohol
摘要： The quantum yield of graphene quantum dots was enhanced by restriction of the rotation and vibration of surface functional groups on the edges of the graphene quantum dots via esterification with benzyl alcohol; this enhancement is crucial for the widespread application of graphene quantum dots in light-harvesting devices and optoelectronics. The obtained graphene quantum dots with highly graphene-stacked structures are understood to participate in π–π interactions with adjacent aromatic rings of the benzylic ester on the edges of the graphene quantum dots, thus impeding the nonradiative recombination process in graphene quantum dots. Furthermore, the crude graphene quantum dots were in a gel-like solid form and showed white luminescence under blue light illumination. Our results show the potential for improving the photophysical properties of nanomaterials, such as the quantum yield and band-gap energy for emission, by controlling the functional groups on the surface of graphene quantum dots through an organic modification approach.
关键词： Optoelectronics,Esterification,Quantum yield,Benzyl alcohol,Graphene quantum dots
更新于2025-11-19 16:46:39
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Influence of water-controlled release process on the physical and chemical property of nanosize TiO <sub/>2</sub> particles
摘要： The water-controlled release process (WCRP) was utilized for the synthesis of TiO2 photocatalyst. The effect of alkylated esterified WCRP system on the morphology, specific surface area (SSA) and photocatalytic activity of TiO2 were studied systematically. By changing the structure of alcohol and acid involved in the esterification reaction, we found that the SSA and photocatalytic activity of TiO2 obtained in an ethanol/acetic acid reaction mixture showed the best results. Interestingly, the TiO2 obtained in t-butanol/acetic acid contains both the anatase and rutile phase, while the other systems only possessed anatase phases. The conditions of ethanol and acetic acid esterification were optimized and the experimental results showed that the SSA of nano-TiO2 was improved by shorting the reaction time or adding an organic solvent, which can form an azeotrope with water, but no effect on the photocatalytic activity could be observed. The reaction mechanism of esterified WCRP system was furthermore studied by NMR spectroscopy, showing three kinds of reaction, namely esterification, etherification and hydrolysis.
关键词： water-controlled release process(WCRP),p-toluenesulfonic acid,esterification,photocatalytic,titania
更新于2025-11-14 17:04:02
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Synthesis of new zinc (II) phthalocyanine conjugates with block copolymers for cancer therapy
摘要： Synthetic routes towards new conjugates of hydrophilic zinc(II) phthalocyanine (ZnPc) with poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic P123) and poly(L-lactide) (PLLA), are described. The main semiproduct ZnPc was obtained by heating 4-nitrophthalimide with urea and zinc chloride, followed by the reduction step. Steglich esterification was used to synthesize two ZnPc-conjugated block copolymers, further utilized in fabrication of polymeric micelles (PMs) - functionalized with the zinc(II) phthalocyanine-type moiety. Biological evaluation of the PMs indicated an acceptable biocompatibility level in accord with requirements in the field of nanotheranostics and nanomedicine.
关键词： fluorescent polymeric micelles,cyclotetramerization,Steglich esterification,in vitro biological evaluation,ZnPc-conjugated block copolymers,diagnostic marker
更新于2025-09-23 15:22:29
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Refluxed Esterification of Fullerenes Conjugated P25 TiO2 Promotes Free Radical Scavenging Capacity and Facilitates Anti-aging Potentials in Human Cells
摘要： Titanium dioxide nanomaterials have good capability to prevent human cells from damage under UV irradiation. However, some studies indicated that the nanoscale of titanium dioxide could potentially cause harmful effects such as free radicals generation under UV irradiation and thereby accelerate the progress of cell aging. Fullerenes can scavenge large amounts of free radicals due to the fact that fullerenes contain enormous amount of π electrons with low lying lowest unoccupied molecular orbital (LUMO), but its adverse properties, such as the poor solubility in water, restricted the applicability. In this study, we employed water-soluble carboxylic acid fullerenes (C60-COOH and C70-COOH) as the free radical scavenger and modify onto the surface of titanium dioxide by refluxed esterification (P25/C60-COOH or C70-COOH) technique. The conformation and properties of theses nanomaterials were characterized by techniques and equipments such as X-ray diffraction (XRD), energy dispersive spectroscopy analysis (EDS), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), and Fourier transform infrared spectroscopy (FT-IR). We also introduced methylene blue (MB) and rhodamine B (Rh B) as indicator to evaluate and demonstrate the scavenging capacity of these nanomaterials. Moreover, we examined the biocompatibility and UV protection capacity of our P25/fullerene composites in human 293T cells, and applied luciferase activity assay to investigate the possible underlying cell protection mechanisms exhibited by these nanomaterials. Our data indicate that both P25/C60-COOH and P25/C70-COOH could protect human cells against UV exposure. P25/C70-COOH exhibits great anti-inflammation capacity, while as P25/C60-COOH exhibits great anti-oxidative stress and anti-DNA damage capacity. Our results suggest that most of our P25/fullerenes composite materials have the ability to reduce free radicals and exhibit high biomedical potential in anti-inflammation, anti-oxidant, and anti-aging applications.
关键词： refluxed esterification,anti-oxidative stress,UV protection,TiO2/fullerene composites,anti-inflammation
更新于2025-09-04 15:30:14