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<i>In-situ</i> Biomineralization of Cu <sub/>x</sub> Zn <sub/>y</sub> Sn <sub/>z</sub> S <sub/>4</sub> Nanocrystals within TiO <sub/>2</sub> -based Quantum Dot Sensitized Solar Cell Anodes
摘要： CuZnSnS (CZTS) quantum dots (QDs) have potential application in quantum dot sensitized solar cells (QDSSCs); however, traditional synthesis approaches typically require elevated temperatures, expensive precursors, and organic solvents that can hinder large scale application. Herein we develop and utilize an enzymatic, aqueous phase, ambient temperature route to prepare CZTS nanocrystals with good compositional control. Nanoparticle synthesis occurs in a minimal buffered solution containing only the enzyme, metal chloride and acetate salts, and L-cysteine as a capping agent and sulfur source. Beyond isolated nanocrystal synthesis, we further demonstrate biomineralization of these particles within a preformed mesoporous TiO2 anode template where the formed nanocrystals bind to the TiO2 surface. This in-situ biomineralization approach facilitates enhanced distribution of the nanocrystals in the anode and, through this, enhanced QDSSC performance.
关键词： Copper Zinc Tin Sulfide,Quantum Dot Sensitized Solar Calls (QDSSC),Nanocrystals,Green Synthesis,Quantum Dots,Biomineralization
更新于2025-09-12 10:27:22
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Ultrasonic and microwave assisted extraction as rapid and efficient techniques for plant mediated synthesis of quantum dots: green synthesis, characterization of zinc telluride and comparison study of some biological activities
摘要： In this study, a simple, rapid, and efficient plant-mediated green approach was presented for the synthesis of stable and ultra-small zinc telluride quantum dots (ZnTe QDs) using the aqueous extract of the Ficus johannis plant. Two modern techniques, namely ultrasonic and microwave techniques, were applied to prepare the plant extracts, which were then used as stabilizing precursors in the synthesis of ZnTe QDs. The synthesized samples were characterized via different techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption, photoluminescence and Fourier transform infrared spectroscopy. The TEM images confirmed the formation of ultra-small nanoparticles with an average size of 8 nm. According to the optical characterization, a wide absorption band around 390 nm and an intense emission peak at 463 nm clarified the successful synthesis of ZnTe QDs. After synthesis and characterization, the antioxidant, antimicrobial, and antifungal potentials of the as-prepared QDs as well as the plant extracts were examined by different tests, comparatively. In addition, the determination of the total phenolic and flavonoid contents of the as-prepared samples was carried out. Moreover, the toxicity of the samples was investigated by Artemia uramiana from their brine shrimp lethality potentials. In the cytotoxicity tests, the inhibition of root growth was considered as an indicator to evaluate the cytotoxicities of the samples.
关键词： Ultrasonic,quantum dots,microwave,biological activities,extraction,green synthesis,zinc telluride
更新于2025-09-11 14:15:04
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Size controlled, time-efficient biosynthesis of silver nanoparticles from <i>Pleurotus florida</i> using ultra-violet, visible range, and microwave radiations
摘要： Monodisperse silver nanoparticles (AgNPs) were synthesized from cell free extracts of edible fungus Pleurotus florida by different electro-magnetic radiations, microwave, visible light and ultra-violet rays. The UV–vis spectroscopy of these nano-silver sols indicated the absorption maxima in 425–500 nm range. Synthesized nano-Ag sols had near spherical particles with nano-scale dimensions embedded in a matrix. Microwave irradiation led to synthesis of mono-disperse AgNPs of size (cid:1)10 nm within 150 s of exposure. However, visible light and ultra violet radiations led to synthesis of polydisperse AgNPs with inconsistent dimensions. The Fourier transform infrared spectroscopy of AgNPs elucidated the presence of molecules of fungal origin besides the vibrational peaks for Ag-O bond. The fungal proteins showed novel conformations upon capping the nanoparticles. The antibacterial activity of the AgNPs against gram positive and negative pathogens was assessed to determine their potential applications in silver-loaded antibacterial materials.
关键词： TEM,Pleurotus,green synthesis,Silver nanoparticles
更新于2025-09-11 14:15:04
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Green synthesized plasmonic nanostructure decorated TiO2 nanofibers for photoelectrochemical hydrogen production
摘要： We herein present the Au and Ag NPs synthesized via chemical reduction with green synthesized carbon nanolights (CNL) as a visible light photosensitizer for TiO2 nanofibers (TNFs) towards photoelectrochemical water splitting. The synthesized photoanodes (PA1: TNFs, PA2: Ag@CNLs/TNFs and PA3: Au@CNLs/TNFs) were probed ex-situ for morphological, structural, optical and electronic properties before being used for the PEC experiments. We first show the efficient photocatalytic activity of these photoanodes for the degradation of methylene blue under visible light irradiation. Followed by the photoelectrochemical (PEC) water splitting investigation, which reveals the substantially improved photocurrent density to 13 mA/cm2 and 18 mA/cm2, for PA2 and PA3, respectively under simulated AM 1.5 solar illumination at 1.36 V vs RHE, ~15 fold enhancement compared to that obtained for a PA1. This improvement we attributed to the synergic consequence, improved absorption and effective charge carrier separation & transport due to surface plasmonic effect, which is well evident in the decrease of measured charge transfer resistance (Rct), for PA2 (15.1 Ω) and PA3 (6.71 Ω), as compared to PA1 (139 Ω).
关键词： TiO2 nanofibers,Green synthesis,Hydrogen,Photo-electrochemical,Carbon quantum dots,Plasmonic nanostructures
更新于2025-09-11 14:15:04
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Green synthesized CeO <sub/>2</sub> quantum dots: a study of its antimicrobial potential
摘要： Cerium oxide (CeO2) nanoparticles (NPs) of size ～4 nm were successfully synthesized by green synthesis method using cerium nitrate as precursor and aloe-vera leaf extract as reducing and stabilizing agent. The switching between Ce3+ and Ce4+ state by reaction with H2O2 inferred the biomedical applications of CeO2 NPs. This switching enhances due to the presence oxygen vacancies and that was con?rmed by photoluminescence spectrum. The SEM images showed spherical morphology of cubic ?uorite structured CeO2 NPs which avoids the harming of cell. In the present study, CeO2 NPs show signi?cant inhibition effect on gram negative bacteria, E. coli and P. aeruginosa which are responsible for food poisoning. Thus study analyze the synthesized CeO2 NPs as promising candidates for removal of biological pollutants and thus have great potential in the environmental remediation.
关键词： antimicrobial activity,green synthesis,quantum dots
更新于2025-09-11 14:15:04
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Synthesis of green cool pigments (CoxZn1-xO) for application in NIR radiation reflectance
摘要： Reconciling green synthesis, sustainability and production of pigments for protection of solar radiation is a continuous topic of search for unique, versatile and environmental compatible methods. In this perspective, we present the green synthesis of inorganic pigments with reflective properties of infrared radiation in the NIR region. Green powder pigments described by CoxZn1-xO, were obtained via the gelatinization method of starch colloidal suspension with inorganic salts (zinc and cobalt), calcined at different temperatures. Structural, morphological and spectroscopic characterization showed the pigments present Wurtzite crystalline phase with compact hexagonal structure, and monophasic when obtained at a calcination temperature above 800 °C. Colorimetric measurements obtained by the CIE-L*a*b* method presented values related to green pigments attributed to cobalt ions, which replace the zinc ions in the Wurtzite matrix and corroborate the composition estimated by X-ray fluorescence analysis for Co0.1Zn0.9O. The pigments' NIR reflectivity increased with the calcination temperature increasing, with R% > 35%; and when the pigment is dispersed in a white paint the increase is R% > 50%. Therefore, our green pigments present great potential to be used as an active material in cold coatings and in solar devices.
关键词： Colorimetry,NIR reflectance,Cool pigments,Green synthesis
更新于2025-09-10 09:29:36
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Preparation of Cerium Oxide Nanoparticles in Salvia Macrosiphon Boiss seeds Extract and Investigation of Their Photo-catalytic Activities
摘要： Cerium oxide nanoparticles (CNPs) with desired particle size and spherical morphology were prepared from cerium nitrate in bio media of Salvia macrosiphon Boiss seeds extract, as a green synthesis route. Then they were characterized by XRD, UV-Vis and FTIR spectroscopies, FESEM and TGA. Band gap energy of the prepared powders was also determined which was found in the range of 2.5 to 3.5 eV. Determination of DLS and zeta potential were showed that CNPs had small size and unique colloidal stability, respectively. Then the photo-catalytic activity of them was investigated by degradation of Rhodamine B (RhB) dye as a model of waste water pollutants, under UV-irradiation and optimum conditions were evaluated. Results showed that decreasing the particle size increased the rate of photo-catalytic reaction remarkably but ascending the band gap energy, in contrast. The photo-catalytic mechanism was also studied by using different scavengers.
关键词： Rhodamine B,Cerium Oxide nanoparticles,Dye,Green synthesis,Photo-degradation,Salvia seeds extract
更新于2025-09-10 09:29:36
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Synthesizing, characterizing, and toxicity evaluating of Phycocyanin-ZnO nanorod composites: A back to nature approaches
摘要： C-Phycocyanin pigment was purified from a native cyanobacterial strain using a novel consecutive multi-step procedure and utilized for the first time for the green synthesis of phycocyanin-zinc oxide nanorods (PHY-ZnO NRs) by a simple, low-cost and eco-friendly approach. The PHY-ZnO NRs were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential measurement, FTIR, SEM, TEM, differential scanning calorimetry (DSC), thermogravimetric (TGA), and EDX spectroscopy analysis. The UV-Vis spectra showed an absorption band at 364 nm which is characteristic of ZnO nanoparticles (ZnONPs). The rod-shaped PHY-ZnO NRs observed in the TEM and SEM images had an average diameter size of 33 nm, which was in good agreement with the size calculated by XRD. The elemental analysis of PHY-ZnO NRs composition showed that three emission peaks of zinc metal and one emission peak of oxygen comprised 33.88% and 42.50%, respectively. The thermogram of PHY-ZnO NRs sample exhibited the weight loss of biosynthesized nanoparticles registered to be 3 %, emphasizing the purity and heat stability of zinc oxide nanorods coated with phycocyanin pigment-protein. MTT assay indicated that PHY-ZnO NRs had a less cytotoxicity on fibroblast L929 compared to the ZnONRs-treated cells. A remarkable increase in ROS level was measured in cells treated with ZnO at final concentrations of 100, 200 and 500 μg/ml (78±7, 99±8 and 116±11, respectively). When it comes to PHY-ZnO NRs, a protective effect for phycocyanin was detected which declined the level of ROS content as confirmed by fluorescent microscopy. The distinctive features of phycocyanin for surface functionalization of ZnO nanoparticles deserve to be deemed as a nano-drug candidate for further researches.
关键词： Cyanobacteria,Green synthesis,MTT assay,Phycocyanin,Zinc oxide nanoparticles
更新于2025-09-10 09:29:36
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Potentials of Costus woodsonii leaf extract in producing narrow band gap ZnO nanoparticles
摘要： Narrow band gap zinc oxide (ZnO) nanoparticles (NPs) were synthesized using unboiled and boiled leaf extracts of Costus woodsonii. The as-synthesized NPs were characterized using a range of techniques. The as-synthesized ZnO NPs were crystalline with a hexagonal wurtzite structure similar to the commercial ZnO (ZnO-C). The maximum absorbance was observed at ~390 nm for ZnO-C and the as-synthesized ZnO NPs (ZnO-UL and ZnO-BL) showed a red shift, i.e. ~448 nm to ~462 nm, hence, a lower band gap of ~2.68–2.77 eV. The band gap energy of the as-synthesized ZnO NPs was lower than that of commercial ZnO. The surface of ZnO was coated/modified with the components of the leaf extract. The as-synthesized ZnO NPs showed similar particle sizes and were spherical in shape. These studies confirmed the green synthesis of ZnO NPs using Costus woodsonii and the significantly reduced band gap (Eg = ~2.68 eV to ~2.77 eV) of the as-synthesized ZnO NPs compared to the ZnO-C (Eg = 3.18 eV).
关键词： Costus woodsonii,Zinc Oxide,Metal oxides,ZnO,Green synthesis,Leaf extracts
更新于2025-09-10 09:29:36
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Green Synthesis of High Temperature Stable Anatase Titanium Dioxide Nanoparticles Using Gum Kondagogu: Characterization and Solar Driven Photocatalytic Degradation of Organic Dye
摘要： The present study reports a green and sustainable method for the synthesis of titanium dioxide (TiO2) nanoparticles (NPs) from titanium oxysulfate solution using Kondagogu gum (Cochlospermum gossypium), a carbohydrate polymer, as the NPs formation agent. The synthesized TiO2 NPs were categorized by techniques such as X-Ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy analysis, Raman spectroscopy, scanning electron microscope- Energy-dispersive X-ray spectroscopy (SEM-EDX), Transmission electron microscopy (TEM), High-resolution transmission electron microscopy (HR-TEM), UV-visible spectroscopy, Brunauer-Emmett-Teller (BET) surface area and particle size analysis. Additionally, the photocatalytic actions of TiO2 NPs were assessed with regard to their ability to degrade an organic dye (methylene blue) from aqueous solution in the presence of solar light. Various parameters affecting the photocatalytic activity of the TiO2 NPs were examined, including catalyst loading, reaction time, pH value and calcination temperature of the aforementioned particles. This green synthesis method involving TiO2 NPs explores the advantages of inexpensive and non-toxic precursors, the TiO2 NPs themselves exhibiting excellent photocatalytic activity against dye molecules.
关键词： methylene blue,titanium dioxide nanoparticles,gum kondagogu,green synthesis,photocatalysis
更新于2025-09-09 09:28:46