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Photoluminescence enhancement <i>via</i> microwave irradiation of carbon quantum dots derived from solvothermal synthesis of <scp>l</scp> -arginine
摘要： Photoluminescence enhancement of carbon quantum dots was achieved via solvothermal synthesis followed by microwave irradiation. Nitrogen and phosphorous doped carbon quantum dots were prepared by solvothermal heating of L-arginine with phosphoric acid for 12 hours followed by microwave irradiation for 3 minutes. The photoluminescence enhancement was nearly two fold after microwave irradiation. The morphology, structure, and surface properties were the same for the solvothermal (CQDs-S) as well as after microwave (CQDs-M) irradiation. Thus, the enhancement is attributed to the decrease of surface defects within CQDs, which led to a decrease in the non-radiative transitions. The CQDs were quenched selectively by Fe3+ ions. The quenching led to the fabrication of the fluorescence probe for ferric ion determination. The CQDs-M had a low detection limit of 4.0 nM, while CQDs-S had a limit of 50 nM. This study gives a tool for enhancing photoluminescence quantum yields, which is highly desired for biosensing and bioimaging applications.
关键词： Photoluminescence enhancement,Fluorescence probe,Solvothermal synthesis,Ferric ion determination,Microwave irradiation,Carbon quantum dots
更新于2025-11-19 16:56:42
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Direct carbonization of organic solvent toward graphene quantum dots
摘要： The bottom-up synthesis of graphene quantum dots (GQDs) using solvothermal method has attracted considerable attention because of their fewer defects and controllable size/ morphology. However, the influence of organic solvent on the preparation of GQDs is still unknown. Herein, a systematic study about carbonization of organic solvents toward GQDs is reported. Results show that organic solvent with the double bond or benzene ring or double hydrophilic groups could be directly decomposed into GQDs without the addition of catalysts or molecule precursors. The as-synthesized GQDs demonstrate ultra-small size distribution, high stability, and excitation wavelength-tunable and upconverted fluorescence. Both hematological and histopathological analyses studies show that the as-synthesized GQDs demonstrate a much good safety profile and excellent biocompatibility. The versatility of this synthetic strategy allows easy control of the surface group, composition, and optical properties of GQDs at the molecular level.
关键词： organic solvents,biocompatibility,fluorescence,graphene quantum dots,solvothermal synthesis
更新于2025-09-23 15:21:01
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Enhanced photocatalytic activity based on TiO <sub/>2</sub> hollow hierarchical microspheres/reduced graphene hybrid
摘要： A novel TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid was prepared by a facile and efficient two-step solvothermal synthesis method. The TiO2 HHMs with the size ～500 nm were uniformly distributed on the surface of rGO nanosheets. The as-prepared TiO2 HHMs/rGO hybrid is stable and exhibits a significantly higher photocatalytic activity (97.8%) for 40 ml of 10 mg/Rhodamine B (RhB) solution than that of the pure TiO2 microspheres (75.2%) and Degussa P25 (53.6%). The rGO nanosheet acts as a microelectrode for rapid accepting and separating the photogenerated electron on surface, which effectively slow the recombination rate of electrons and holes, and then effectively enhance the photocatalytic activity of the hybrid. The as-prepared novel TiO2 HHMs/rGO hybrid shows great promising for practical photocatalytic applications.
关键词： TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid,enhancement,photocatalytic activity,two-step solvothermal synthesis
更新于2025-09-23 15:21:01
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Morphological control of TiO2 nanocrystals by solvothermal synthesis for dye-sensitized solar cell applications
摘要： TiO2 nanocrystals TETA1, TPRA2, TIPA3, TBUA4, TTBA5, and TBNA6 were prepared using ethanol, 1-propanol, isopropyl alcohol, n-butanol, tert-butyl alcohol, and benzyl alcohol, through the alcohol-based solvothermal method. The morphology, size, and crystallinity of the TiO2 nanocrystals were characterized utilizing transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and high-resolution transmission electron microscopy analyses. These six TiO2 nanocrystals with different morphologies were used as photoanodes in dye-sensitized solar cells (DSSCs) and their cell efficiencies were 8.08 % (TETA1), 8.38 % (TPRA2), 9.18 % (TIPA3), 7.68 % (TBUA4), 7.85 % (TTBA5), and 6.10 % (TBNA6). Among them, the well dispersed rod-shaped one-dimensional TiO2 (TIPA3) photoanode based cell showed the best power conversion efficiency due to its highest dye loading and excellent light-harvesting capacity. This TIPA3 cell demonstrated a fast electron transport rate with suppressed charge recombination which was confirmed from electrochemical impedance spectroscopy.
关键词： dye loading,TiO2 nanocrystals,power conversion efficiency,solvothermal synthesis,dye-sensitized solar cells
更新于2025-09-23 15:19:57
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One-step <i>in situ</i> synthesis of BiOCl/(BiO) <sub/>2</sub> CO <sub/>3</sub> composite photocatalysts with exposed high-energy {001} facets
摘要： Tailoring the chemical composition and morphology of a composite photocatalyst is a key way to achieve superior photocatalytic activity. In this work, a simple method has been developed to controllably prepare BiOCl/(BiO)2CO3 composite photocatalysts with exposed {001} facets. The chemical composition and morphology of the BiOCl/(BiO)2CO3 composites can be easily tuned by simply changing the ethanol/water volume ratio in the initial reaction system. The precursor of guanidine hydrochloride not only acts as the source of chloride and carbonate ions to form the BiOCl/(BiO)2CO3 composites, but also acts as the crystal growth inhibitor to control the growth of BiOCl nanosheets. The composites exhibit superior photocatalytic activity towards the degradation of rhodamine B under visible light irradiation, which can be ascribed to the type-II band alignment and intimate interfacial contacts between BiOCl nanosheets and (BiO)2CO3 nanoparticles, as well as their exposed high-energy facets. Both the formation mechanism of the BiOCl/(BiO)2CO3 composite and the photocatalytic degradation mechanism have been investigated and proposed.
关键词： BiOCl/(BiO)2CO3 composite,solvothermal synthesis,exposed {001} facets,photocatalytic degradation,photocatalyst
更新于2025-09-19 17:15:36
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Exploration of the Potential Efficacy of Natural Resource Derived Blue Emitting Graphene Quantum Dots in Cancer Therapeutic Application
摘要： Coal is the most abundant natural resource being used worldwide and shows graphite-like clusters. Here, we report an innovative and cost effective oxidative functionalization approach followed by acid-free and oxone oxidant-assisted solvothermal synthesis of graphene quantum dots from coal for the first time. This oxidative functionalization method of coal has been performed through heat treatment of nitric acid followed by acid recovery process. Indeed, solvothermal method is entirely free from the utilization of strong acids; and involves a simple, eco-friendly, and salt free purification process with high production yield (~45%). Due to the synergistic synthesis technique, our developed GQDs are found to exhibit a strong blue photoluminescence (PL) characteristic with significantly high quantum yield (~14.42 %). High resolution Transmission electron microscopy (HRTEM) images indicate that nanocrystalline GQDs have uniform and narrow particle size distribution in the range of 2.5-5 nm. The anticancer efficacy of the synthesized GQDs nano material is validated through cellular morphological pattern analysis and DAPI stain images of neuroblastoma cell and breast cancer cell. Additionally, the alteration of mitochondrial membrane potential is scrutinized using JC1 micrographs. Interestingly, RITC tagged GQDs are showing cellular internalization within breast cancer cells. The robust functionality, luminescence stability, nanosecond lifetime, biocompatibility and low toxicity of our developed GQDs enable them to be promising probes for cancer therapeutic applications. This study unveils new opportunities for sustainable production of GQDs with novel attributing features because of the easily available of raw material, cost-effective productivity and fascinating photoluminescence property.
关键词： Oxidative functionalization,Coal,Cancer cell,Photoluminescence,Solvothermal synthesis
更新于2025-09-19 17:13:59
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Controlled Growth and Bandstructure Properties of One Dimensional Cadmium Sulfide Nanorods for Visible Photocatalytic Hydrogen Evolution Reaction
摘要： One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H2). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication of highly efficient photocatalysts. Herein, 1D CdS nanorods (NRs) were synthesized by a facile and low-cost solvothermal method, in which reaction time played a significant role for increasing the length of CdS NRs from 100 nm to several micrometers. It is confirmed that as the length of CdS NR increases, the visible photocatalytic H2 evolution activity also increases and the CdS NR sample obtained at 18 hr. reaction time exhibited the highest H2 evolution activity of 206.07 μmol.g-1.h-1. The higher H2 evolution activity is explained by the improved optical absorption properties, enhanced electronic bandstructure and decreased electron-hole recombination rate.
关键词： photocatalytic H2 evolution,bandstructure,CdS nanorods,electron-hole recombination,solvothermal synthesis
更新于2025-09-19 17:13:59
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Binary transition metal sulfides as an economical Pt-free counter electrodes for dye-sensitized solar cells
摘要： Binary CuxCoySz sulfide based Pt-free counter electrodes (CE) were prepared in one-step solvothermal synthesis process. The obtained CEs were characterized by SEM, XRD, and Raman spectroscopy methods. EDX analysis showed uniform distribution of Cu, Co and S. SEM images revealed different level of coverage of the FTO glass by the binary metal sulfide products. DSSCs were constructed using proposed CEs with N719 dye, and their photovoltaic and electrochemical performances were assessed against Pt reference cell. The efficiency of the CuxCoySz-3 CE produced an 11% improvement of its photovoltaic efficiency compared to the reference cell.
关键词： Cu-Co-S complex,SEM,XRD,Solvothermal synthesis,Raman
更新于2025-09-16 10:30:52
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Facile Synthesis of Carbon Nanotubes Covalently Modified with ZnO Nanorods for Enhanced Photodecomposition of Dyes
摘要： Utilizing a one-pot solvothermal procedure novel one-dimensional zinc oxide-carbon nanotube nanohybrids (ZnCT) were synthesized in alcohol-alkali solution, free of catalytic assistance. The ZnCT hybrids were prepared through covalent modification of zinc oxide nanorods (ZnO NRs) with functionalized carbon nanotubes (f-CNTs). The morphology and microstructure of as-prepared ZnCT hybrids were characterized by scanning electron microscopy (SEM), powder X-ray diffraction, Raman, X-ray photoelectron and UV-vis absorption spectroscopies. SEM images of the ZnCT hybrids indicated that the ZnOethanol NRs grew longer along the vertical radial (0001) surface and aggregated to a lesser extent than the analogous ZnOmethanol NRs. Photodegradation analysis showed that the off-white ZnCTethanol hybrid with ascendant UV-visible light absorption had displayed superior photocatalytic activity towards Rhodamine B (RhB) dyes than either pure ZnOethanol, ZnOmethanol NRs or ZnCTmethanol hybrid, among which the photocatalytic activity of ZnOethanol NRs was better than that of ZnOmethanol NRs. Raman and X-ray photoelectron spectroscopy analyses confirmed a strong interaction between f-CNTs and ZnOethanol NRs in ZnCTethanol hybrid, in which Zn ions were chemically bonded to negatively charged oxygen-containing groups at the graphene-like surface of f-CNTs. The enhanced separation lifetime of the photogenerated electron-hole observed by surface photovoltage and photocurrent measurements of the ZnCTethanol hybrid was attributed to the efficient covalent linking of Zn-O-C and close contact configuration between the f-CNTs and ZnOethanol NRs. Further controlled photodegradation and electron spin resonance (ESR) analyses revealed that the photodegradation of RhB dyes resulted from photogenerated holes, and radical species, such as ?O2?、?OH?, which were formed in-situ. Details of the photocatalytic mechanism were also explored herein.
关键词： Solvothermal synthesis,ZnO nanorods,Carbon nanotubes,Dyes,Photodegradation
更新于2025-09-10 09:29:36
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PVP intercalated metallic WSe<sub>2</sub> as NIR photothermal agents for efficient tumor ablation
摘要： Transition metal dichalogenides (TMDCs) with unique layered structures hold promising potential as transducers for photothermal therapy. However, the low photothermal conversion efficiency and poor stability in some cases limit their practical applications. Herein, we demonstrate the fabrication of an ultrathin homogeneous hybridized TMDC nanosheets and their use for highly efficient photothermal tumor ablation. In particular, the nanosheets were composed of metallic WSe2 intercalated with polyvinylpyrrolidone (PVP), which was facilely prepared through a solvothermal process from the mixture of selenourea crystals, WCl6 powder along with PVP polymeric nanogel. Our characterizations revealed the obtained nanosheets exhibited excellent photothermal conversion efficiency, improved biocompatibility and physiological stability attributing to the combined merits of metallic phase of WSe2 and hydrophilic PVP insertion. Both the histological analysis of vital organs and in-vitro/in-vivo tests confirmed the nanosheets as actively effective and biologically safe in this phototherapeutic technique. Findings from this non-invasive experiment clearly emphasize the explorable therapeutic efficacy of layered-based hybrid agents in future cancer treatment planning procedures.
关键词： Solvothermal synthesis,intercalation,metallic tungsten diselenide,photothermal therapy
更新于2025-09-10 09:29:36