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Dy(III)-induced aggregation emission quenching effect of single-layered graphene quantum dots for selective detection of phosphate in the artificial wetlands
摘要： Carbon quantum dots (CQDs), prepared by one-step hydrothermal treatment of perylene-3,4,9,10-tetra-carboxylic dianhydride (PTCDA) and triethylamine (TEA), could be exfoliated or delaminated into single-layered graphene quantum dots (s-GQDs) with methanol for the first time, with fluorescence (FL) emission at 500 nm when excited at 417 nm. The s-GQDs, with more sufficient carboxyl groups on the surface than CQDs, could be induced to be aggregated by metal ion dysprosium (Dy3+), resulting in aggregation-induced emission quenching effect subsequently. However, the presence of phosphate (PO4 3-) destroys the Dy3+-induced aggregates of s-GQDs owing to the strong coordination between Dy3+ and PO4 3-, inducing the FL emission recovery of the s-GQDs and providing selective detection method of PO4 3- in the artificial wetlands with the linear range of 0.2–30 μM and determination limit of 0.1 μM (3σ).
关键词： s-GQDs-Dy3+ system,Phosphate detection,Single-layered graphene quantum dots,Carbon quantum dots
更新于2025-11-14 17:04:02
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Facile and one-step preparation carbon quantum dots from biomass residue and their applications as efficient surfactants
摘要： Using biomass residue as a source of carbon precursors, a pyrolysis method was used to prepare biomass-derived luminescent Carbon Quantum Dots (CQDs). The prepared CQDs exhibited excellent fluorescence and luminescence properties and fluorescence behaviors of CQDs acquired at different pyrolysis temperatures varied. Importantly, the CQDs showed superior surface activity and the styrene-in-water Pickering emulsion prepared using the CQDs as nano-sized surfactant was highly stable: the higher the pyrolysis temperature the better the stability of the emulsion. In addition, there was no stratification found in the emulsion which was stabilized by the CQD500 (CQDs prepared at 500 (cid:1)C) after holding for 72 hours. This research provided an approach for preparing the surfactants of nano-sized particles in large scale. The CQDs prepared using the proposed methods are expected to have a high number of potential applications.
关键词： biomass,nano-sized surfactant,Carbon Quantum Dots,stability,pickering emulsion
更新于2025-11-14 17:04:02
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Gold doping induced strong enhancement of carbon quantum dots fluorescence and oxygen evolution reaction catalytic activity of amorphous cobalt hydroxide
摘要： Gold doping induced strong enhancement of carbon quantum dots fluorescence and oxygen evolution reaction catalytic activity of amorphous cobalt hydroxide. Water splitting using electrocatalysts is expected to provide an alternative green energy source to meet increasing energy demands as well as addressing environmental concerns related to fossil fuels. Herein, we report one-step synthesis of sulfur, nitrogen and Au-doped carbon quantum dots (Au-SCQDs) and strong enhancement of fluorescence intensity and oxygen evolution reaction (OER) catalytic activity of amorphous Co(OH)2 nanoparticles compared to pure Co(OH)2 as well as commercial RuO2 and Pt/C catalysts. Au doping into sulfur and nitrogen co-doped CQDs showed over seventy times enhanced fluorescence. OER studies of amorphous-Co(OH)2 incorporated Au-SCQDs produced current density of 178 mA cm?2 at the applied potential of 2.07 V whereas un-doped Co(OH)2 showed current density of 59 mA cm?2. To produce geometric current density of 10 mA cm?2, amorphous Co(OH)2-Au-SCQDs (CSA) required 388–456 mV overpotential depending on the Au ion concentration used for preparing the Au-SCQDs, which is equal to or lower than overpotential required by commercial electrocatalysts. The strongly enhanced OER activity of Co(OH)2-Au-SCQDs (CSA) was attributed to the presence of electronegative metallic conducting Au atoms along with the high catalytic surface area of amorphous Co(OH)2. The present studies demonstrate a new method of exploiting amorphous Co(OH)2NPs electrocatalysts that could provide more catalytically active sites by integrating an electronegative conducting Au atom doped SCQDs matrix.
关键词： amorphous cobalt hydroxide,fluorescence,water splitting,Gold doping,carbon quantum dots,oxygen evolution reaction,electrocatalysts
更新于2025-10-22 19:40:53
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Carbon quantum dots-decorated TiO2/g-C3N4 film electrode as a photoanode with improved photoelectrocatalytic performance for 1,4-dioxane degradation
摘要： In this study, carbon quantum dots (CQDs) were used to decorate a TiO2/g-C3N4 (TCN) film electrode. The morphological, optical, and electrochemical properties of the TiO2/g-C3N4/CQDs nanorod arrays (TCNC NRAs) film were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electro-impedance spectroscopy (EIS). The improved optical properties, photoelectrochemical chemical properties and photoelectrocatalytic (PEC) performance of photoanode can be observed by doping CQDs onto the TCN NRAs film. Compared with TiO2 NRAs and TCN NRAs, the narrower band gap of 2.47 eV and longer lifetime of photoinduced electron-hole pairs were observed in the TCNC NRAs. Under visible light irradiation and a bias voltage of 1.2 V, the photocurrent density and 1,4-dioxane (1,4-D) removal rate of PEC process with TCNC NRAs electrode reached 0.16 mA/cm2 and 77.9%, respectively, which was 2.5 times and 1.5 times of that with TCN NRAs electrode. TCNC NRAs electrode could keep >75% of the 1,4-D removal rate during five cycles tests. High PEC performance with TCNC NRAs electrode could be attributed to the enhanced charge separation and the change of electron transfer mechanism from typical heterojunction to Z-scheme, which may increase the active species production and change the dominant reactive species from O2?- to ?OH. Our experimental results should be useful for studying the degradation of 1,4-D and developing efficient PEC materials.
关键词： Graphite carbon nitride,TiO2 nanorods,1,4-Dioxane,Carbon quantum dots,Photoelectrocatalysis
更新于2025-09-23 15:21:01
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Preparation of ZnO-carbon quantum dot composite thin films with superhydrophilic surface
摘要： Carbon quantum dots (CQDs)-ZnO composite thin films were prepared via ultrasonic mist vapour deposition (UMVD) method. The effect of different CQDs concentrations (C), substrate temperatures (Ts), nozzle-substrate distances and also post-annealing process on the thin film structure were considered and examined systematically. The effects of these parameters on optical, morphological and surface properties of the layers as well as their wettability were carefully investigated and discussed. It was found that for low Ts and short ‘d’, CQDs diffuse inside the layer during deposition and then were evaporated after annealing process making drastic changes in layer morphology and optical transmittance. On the other hand, for high Ts and long ‘d’, most of CQDs inside mist vapour drops are evaporated during deposition process. Therefore, the layer transmittance and morphology did not change notably after annealing. Interestingly, the layer prepared with C = 5 volume %, Ts = 470 °C and d = 9 cm was turned to super-hydrophilic surface after annealing process with contact angle of , 3o. Such a super-hydrophilic CQDS-ZnO thin film is highly beneficial for a wide range of applications which high wettability is required.
关键词： mist vapour deposition,super-hydrophilic,ZnO thin film,Carbon quantum dots
更新于2025-09-23 15:21:01
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The effect of hydrothermal conditions on photoluminescence properties of rice husk-derived silica-carbon quantum dots for methylene blue degradation
摘要： Carbon quantum dots (CQDs) have potential to replace metal-based quantum dots due to its low-toxicity. However, studies on CQDs preparation were dominated by synthetic carbon precursors. Switching the precursors into natural ingredient is preferred since they are highly abundant and low-cost. In this study, composite of silica-carbon quantum dots (Si-CQDs) were fabricated from rice husk through a hydrothermal process. Si-CQDs with diverse properties are beneficial for its application in the future; therefore, the variation of hydrothermal conditions (i.e., temperature and pH) was performed to investigate their influence on its properties. Investigation using HRTEM, XPS, Raman spectroscopy, and UV-Vis spectroscopy suggested that hydrothermal conditions affect carbonization reaction. Hydrothermal temperature controls carbonization rate of rice husk ash, while acid addition accelerates polymerization and base addition tends to cut more carbons into small particles. The photoluminescence (PL) analysis showed that the obtained Si-CQD samples have emission in the range of 469–552 nm with various intensities. The application of sole Si-CQDs was evaluated in methylene blue (MB) degradation under visible light irradiation.
关键词： Hydrothermal,Carbon quantum dots,Photocatalyst,Photoluminescence,Rice husk
更新于2025-09-23 15:21:01
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Protein Corona Formation of Human Serum Albumin with Carbon Quantum Dots from Roasted Salmon
摘要： As the food-borne nanoparticles enter the biological system, they will contact with various proteins to form protein coronas, which can affect their physicochemical properties and biological identity. In this study, the protein corona formation of carbon quantum dots (CQDs) from roast salmon with human serum albumin (HSA), as well as biological identity involving cell apoptosis, energy, glucose and lipid metabolism and acute toxicity in mice, were investigated. The HSA-CQD coronas formed between HSA and CQDs via static binding mechanism, and the binding site of CQDs on HSA located both in Sudlow’s site I and site II. The HSA-CQD coronas entered the cytoplasm and present in lysosomes or autolysosomes. Importantly, the HSA coronas mitigated the cytotoxicity of CQDs from 18.65% to 9.26%, and the energy metabolism was rectified from glycolytic to aerobic metabolism. The glucose and lipid metabolite profile of the HSA-CQD coronas differed from that of the CQDs, indicating that HSA-CQD coronas rectified disturbance in metabolism. Histopathological and blood biochemical analysis revealed no statistically significant difference between the testing and control mice after a single CQDs dose of 2000 mg/kg body weight. Overall, the results confirmed the formation of protein corona between HSA and food-borne fluorescent CQDs, and could be helpful for evaluating the safety of fluorescent CQDs from roast food items.
关键词： cytotoxicity,acute toxicity,protein coronas,human serum albumin,carbon quantum dots,metabolism,food-borne nanoparticles
更新于2025-09-23 15:21:01
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Influence of Carbon Quantum Dots on the Biome
摘要： The latest class of engineered nanomaterials, viz., carbon quantum dots (CQDs), has attracted attention because they are synthesized through green chemical procedures and from organic waste matter. The synthesis of these nano-sized particles synthesized from biomass such as fruit peel and other organic matter results in mixtures of CQD species that di?er in chemical identity, activity and photo-physical properties. Generally used collectively as chemically heterogeneous ensemble, they have already had an impact on multiple sectors of our environment by use as wastewater sensors, switches, model agro-fertilizers, and in biomedicine. The transitioning of their applications to crops is an important crossover point that calls for an accurate and detailed assessment of their genomic, proteomic, and metabolomics impact on agriculturally important crops and produce. We review the current status of CQDs vis-à-vis their impact on the biosphere via recent model studies and comment on the knowledge gaps that need to be bridged to ensure their safe use in agronomy. A detailed knowledge of their impact on aquatic systems and the food-chain is critical for human and environmental safety and sustainability.
关键词： agriculture,environmental implications,Carbon Quantum Dots,toxicity
更新于2025-09-23 15:21:01
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Surface Engineered Hybrid Corea??Shell Sia??Nanowires for Efficient and Stable Broadband Photodetectors
摘要： Silicon nanostructures have gained intensive interest to develop broadband photodetectors at a large-scale due to their excellent electronic properties. Herein, Si-nanowires (SiNWs) decorated with reduced graphene oxide:carbon quantum dots (rGO:CQDs) nanocomposite (NC), as core–shell heterojunction building blocks for broadband (ultraviolet (UV)–near infrared (NIR)) photodetectors (PDs), are demonstrated. The SiNWs and CQDs are synthesized by wet-chemical etching and facile pyrolysis methods, respectively. Photogenerated carriers are transported through rGO because of its high electron mobility and favorable band alignment with CQDs and Si. Further, to minimize the recombination of photogenerated carriers, and enhance the response in the visible region, plasmon-enhanced AuCQDs are incorporated in the shell matrix. The optimized heterostructure (rGO:AuCQDs/undoped CQDs/SiNWs) is sensitive to a broad wavelength range covering the UV to NIR (360 to 940 nm) region, manifests the excellent responsivity of 16 A W?1 at 360 nm, detectivity (D*) of 2.2 × 1013 Jones, and noise equivalent power as low as 2.8 fW Hz?1/2. The optimized PDs heterostructure demonstrates excellent air-stability after 8 days of illumination without any encapsulation or protective coating. The proposed simple, cost-effective, and Si-process-line compatible fabrication of Si-based PD device structure imposes a great promise for highly efficient and stable advanced futuristic optoelectronic devices.
关键词： core–shell heterostructure,detectivity,responsivity,broadband photodetectors,reduced graphene oxide,carbon quantum dots,Si nanowires
更新于2025-09-23 15:21:01
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Strong coupling of carbon quantum dots in plasmonic nanocavities
摘要： Strong coupling of carbon quantum dots in plasmonic nanocavities
关键词： carbon quantum dots,strong coupling,plasmonic nanocavities
更新于2025-09-23 15:21:01