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High-Throughput Fingerprinting of Rhizobial Free Fatty Acids by Chemical Thin-Film Deposition and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry
摘要： Fatty acids (FAs) represent an important class of metabolites, impacting on membrane building blocks and signaling compounds in cellular regulatory networks. In nature, prokaryotes are characterized with the most impressing FA structural diversity and the highest relative content of free fatty acids (FFAs). In this context, nitrogen-fixing bacteria (order Rhizobiales), the symbionts of legumes, are particularly interesting. Indeed, the FA profiles influence the structure of rhizobial nodulation factors, required for successful infection of plant root. Although FA patterns can be assessed by gas chromatography—(GC-) and liquid chromatography—mass spectrometry (LC-MS), sample preparation for these methods is time-consuming and quantification suffers from compromised sensitivity, low stability of derivatives and artifacts. In contrast, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) represents an excellent platform for high-efficient metabolite fingerprinting, also applicable to FFAs. Therefore, here we propose a simple and straightforward protocol for high-throughput relative quantification of FFAs in rhizobia by combination of Langmuir technology and MALDI-TOF-MS featuring a high sensitivity, accuracy and precision of quantification. We describe a step-by-step procedure comprising rhizobia culturing, pre-cleaning, extraction, sample preparation, mass spectrometric analysis, data processing and post-processing. As a case study, a comparison of the FFA metabolomes of two rhizobia species—Rhizobium leguminosarum and Sinorhizobium meliloti, demonstrates the analytical potential of the protocol.
关键词： bacteria,metabolic fingerprinting,matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS),barium monocarboxylates,free fatty acids (FFAs),chemical deposition technique,Langmuir film technology,rhizobia
更新于2025-09-23 15:21:01
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Laser-induced continuous generation of Ni nanoparticles for organic synthesis
摘要： The possibilities of laser-induced liquid phase chemical deposition (LCLD) of metal for continuous generation of nickel nanoparticles, the sizes of which allow their use as a catalyst for organic reactions are considered. The conditions for obtaining Ni nanoparticles by this method were optimized.
关键词： laser-induced liquid phase chemical deposition,catalyst,nickel,nanoparticle,laser-induced deposition,solution
更新于2025-09-12 10:27:22
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ZnO@TiO2 Core Shell Nanorod Arrays with Tailored Structural, Electrical, and Optical Properties for Photovoltaic Application
摘要： ZnO has prominent electron transport and optical properties, beneficial for photovoltaic application, but its surface is prone to the formation of defects. To overcome this problem, we deposited nanostructured TiO2 thin film on ZnO nanorods to form a stable shell. ZnO nanorods synthesized by wet-chemistry are single crystals. Three different procedures for deposition of TiO2 were applied. The influence of preparation methods and parameters on the structure, morphology, electrical and optical properties were studied. Nanostructured TiO2 shells show different morphologies dependent on deposition methods: (1) separated nanoparticles (by pulsed laser deposition (PLD) in Ar), (2) a layer with nonhomogeneous thickness (by PLD in vacuum or DC reactive magnetron sputtering), and (3) a homogenous thin layer along the nanorods (by chemical deposition). Based on the structural study, we chose the preparation parameters to obtain an anatase structure of the TiO2 shell. Impedance spectroscopy shows pure electron conductivity that was considerably better in all the ZnO@TiO2 than in bare ZnO nanorods or TiO2 layers. The best conductivity among the studied samples and the lowest activation energy was observed for the sample with a chemically deposited TiO2 shell. Higher transparency in the visible part of spectrum was achieved for the sample with a homogenous TiO2 layer along the nanorods, then in the samples with a layer of varying thickness.
关键词： TiO2 thin film,optical properties,ZnO nanorods,chemical deposition,DC reactive magnetron sputtering,pulsed laser deposition,electrical properties,core–shell
更新于2025-09-12 10:27:22
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Ferroelectric PZT thin films for photovoltaic application
摘要： The ferroelectric photovoltaic response characteristics of Lead Zirconate Titanate (PZT) thin film in metal-ferroelectric-metal (MFM) configuration is studied under 33 mode upon exposure to UV radiations. PZT thin films of 180 nm are prepared on inter-digital electrodes patterned silicon substrate (with silicon dioxide as insulating layer) using chemical solution deposition (CSD) technique followed by rapid thermal annealing. PZT thin films are found to be in single phase and possess high electrical polarization (50μC/cm2). Significant increase in photocurrent and large value of open circuit voltage (1.0 V) is observed for the prepared ferroelectric photovoltaic film under UV illumination.
关键词： Lead zirconium titanate,Chemical deposition,Polarization,Ferroelectric,Photovoltaics
更新于2025-09-12 10:27:22
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Thin film Sn2S3 via chemical deposition and controlled heating - its prospects as a solar cell absorber
摘要： As a semiconductor of “earth-abundant” elements, Sn2S3 with a bandgap (Eg) close to 1 eV merits attention, but a method to prepare phase-pure thin film remains elusive. We report the formation of Sn2S3 thin film of 360 nm in thickness by heating chemically deposited tin sulfide thin films at 450 oC during 30 – 45 min in presence of sulfur at a pressure, 75 Torr of nitrogen. Energy dispersive x-ray emission spectra and grazing incidence x-ray diffraction established a reaction route for this conversion of SnS completely to Sn2S3 via an intermediate phase, SnS2. The optical bandgap of the material is 1.25 eV (indirect) and 1.75 eV (direct, forbidden). The optical absorption suggests a light-generated current density of 30 mA/cm2 for the Sn2S3 film (360 nm) as a solar cell absorber. Thin film Sn2S3 formed in 30 min heating has a p-type electrical conductivity in the dark of 1x10–4 Ω–1 cm–1, which increases to 3x10–4 Ω–1 cm–1 in 0.2 s under 800 W/m2 tungsten-halogen illumination. An estimate made for its mobility-lifetime product is, 6x10–6 cm2 V–1. We discuss the prospects of this material for solar cells.
关键词： SnS-CUB,Sn2S3,semiconductor thin film,chemical deposition,energy conversion,ottemannite,cubic tin sulfide,renewable energy,optical and electrical properties,solar cells
更新于2025-09-11 14:15:04
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Solution Processable P3HT/CdS Photodiodes and Their Electrical Characterization
摘要： In this work we apply simple layer solution deposition methods for the assembling of CdS/P3HT (poly(3-hexylthiophene)) p-n heterostructures and analyzed their photodetection properties in the visible optical range. The CdS-n layers were deposited on ITO-coated glass substrates by the chemical bath method employing an ammonia-free recipe. The P3HT-p layers were deposited on the CdS/ITO/glass substrates by the casting method from solution by dissolving P3HT in chloroform. As the back electrodes, to complete the p-n heterostructures, carbon (graphite) was used. The electrical properties of the assembled CdS/P3HT hybrid photodiodes in dark and under illumination at several intensities, in the 0-100 mW/cm2 interval, were analyzed from current density versus voltage (J-V) measurements, in the -5V to 5V bias voltage range. From these measurements, the photosensitivity of the photodiodes as a function of bias voltage was determined as 370 mA/W. The response of the photodiodes as a function of illumination intensity was determined from transient photocurrent measurements.
关键词： solution growth,hybrid photodiodes,chemical deposition,photosensors
更新于2025-09-04 15:30:14
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Silicon Film Deposition Using a Gas-Jet Plasma-Chemical Method: Experiment and Gas-Dynamic Simulation
摘要： This paper presents the results of an experimental study, numerical calculation, and analysis within the framework of a gas-dynamic model of silicon ?lm deposition by a gas-jet plasma-chemical method. A numerical model of gas mixtures ?owing out of an annular nozzle unit and into a reactor is developed, and it allows one to determine a ?lm thickness distribution over the surface of substrates placed in the reactor and satisfactorily describes the experimental data obtained.
关键词： reactor,simulation,plasma-chemical deposition,thin silicon ?lms,free jet,electron-beam plasma,DSMC method
更新于2025-09-04 15:30:14