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Thermal Stability of LED Molecules Triphenylamine-Based Aromatic Polyamides: Spectral and Electrochemistry Applications
摘要： By using the aromatic nucleophilic displacement reaction of 4-fluorobenzonitrile with three aniline-derivatives using sodium hydride as the base synthesized new dinitriles intermediates (A-CN), (B-CN) and (C-CN). After alkaline hydrolysis of these resultants three di acid monomers e.g., 4,4'-dicarboxy-4''-ethylenetriphenylamine (A-OH), 4,4'-dicarboxy-4''-isopentyl-triphenylamine (B-OH), 4'-dicarboxy-4''-phenoxy-triphenylamine (C-OH) were obtained. A series of poly(amine-amide)s were prepared by the phosphorylation poly-condensation reaction with different aromatic diamines. The chemical structures of all the resultant compounds and poly(amine-amide)s were identified by FTIR, 1H and 13C NMR techniques. These aromatic poly(amine-amide)s exhibited excellent thermal stability with high glass transition temperatures (Tg). Solutions diluted in N-methyl pyrrolidone of these polyamides appeared a strong UV-visible absorption in the blue region. These polymers exhibited cyclic voltammetry of the resulting polyamides films cast onto an ITO-coated glass substrate in dry acetonitrile containing 0.1 M of tetrabutylammonium perchlorate as an electrolyte exhibited one oxidation redox couples.
关键词： LED-molecules,Emitting diodes,Thin layer
更新于2025-11-19 16:56:42
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A thin-layer dielectric and metamaterial unit-cell stack loaded miniaturized SRR-based antenna for triple narrow band 4G-LTE applications
摘要： This article presents the design of a miniaturized dual-band antenna for long-term evolution (LTE) application is presented. In the basic antenna design, split ring resonator was loaded in the radiating plane of the patch and frequency of resonance was further modified with the help of E-shaped stub. The antenna has been fabricated using FR-4 substrate and the measured dual bands at 2.11 and 2.665 GHz are found in a close match with the simulated data. By placing a thin dielectric resonator of permittivity εr = 10.2 and thickness of 1.27 mm, two closely spaced narrow bands are obtained at 2.217 and 2.28 GHz. A novel metamaterial unit-cell having near-zero refractive index is designed and mounted above the dielectric resonator. This stack configuration generates triple narrow frequency band in the LTE 2 GHz spectrum range. The overall size of the proposed antenna is 20 × 25 mm2.
关键词： triple band,split ring resonator,thin layer dielectric resonator,reflection coefficient,patch,unit-cell
更新于2025-09-23 15:23:52
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Comparative study of conventional and inverted P3HT: PCBM organic solar cell
摘要： This work is a comprehensive comparative study between conventional and inverted bulk hetero-junction (BHJ) Organic Solar Cell (OSC and IOSC) using GPVDM software. Contrary to conventional OSCs with a low work-function cathode located on the top, IOSC is characterized by a bottom transparent conductive oxide cathode. The calculated current-voltage characteristic (J-V) is used to extract the main electrical outputs (figures of merit) of the solar cell: the short circuit current (Jsc), the open circuit voltage (Voc), the fill factor (FF) and the efficiency (η). The effect of a number of physical parameters is studied including thickness of the different layers and materials used as electron (hole) transport layer, ETL (HTL). In addition, different top and bottom electrodes are suggested with mono and multi-thin layer. A comparison between the effect of all these factors in OSC and IOSC is also performed and it was found that IOSC using multi-thin layer ATZ (AZO/TiOx/ZnO) as bottom contact gives the best efficiency of 5.46% in comparison with 5.02% obtained for the conventional OSC with ZnO/TiOx/ZnO contact.
关键词： Organic solar cells,Inverted structure,Bulk hetero-junction,GPVDM Software,Multi-thin layer electrodes
更新于2025-09-23 15:19:57
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Optimization of structural and optical properties of nanoporous silicon substrate for thin layer transfer application
摘要： A study on optical and structural properties of nanoporous silicon is presented in this paper. The samples were prepared by electrochemical etching a heavily boron doped silicon wafer in a hydrofluoric acid electrolyte and flowed by in-situ sintering in ultra-high vacuum chemical vapor deposition reactor (UHVCVD) under hydrogen atmosphere at high temperature varied between 900 and 1100 °C. The structural and morphological properties were carried out using atomic force microscopy (AFM), scanning electronic microscopy (SEM) and high resolution transmission electronic microscopy (HRTEM). The optical properties were performed using the photoluminescence Spectroscopy (PL), Time Resolved Photoluminescence (TRPL), RAMAN spectroscopy and Fourier-transform infrared spectroscopy (FT-IR). It is shown that the in-situ heating at 900 °C desorbs the native oxide from the porous layer and closes the pores forming a continuous defects-free surface at the top of porous layer. The process allows obtaining stable porous layer with enhanced structural and optical properties and also tailoring the morphological properties and the visible optical emission. This paper aims at a comprehensive determination of the physical properties of sintered porous silicon, in particular, its structural and optical properties.
关键词： structural properties,optical properties,nanoporous silicon,thin layer transfer,sintering
更新于2025-09-23 15:19:57
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Mass spectrometry imaging of thin-layer chromatography plates using laser desorption/low-temperature plasma ionisation
摘要： Thin-layer chromatography (TLC) is a classic method for the separation and analysis of complex mixtures. Biological assays, chemical derivatisation and spectroscopy techniques are compatible with TLC and provide extra information about isolated compounds. However, coupling TLC to mass spectrometry is hampered by the difficulty to desorb the analytes from the silica surfaces. In this study, we used a multimodal ion source for laser desorption (LD) and low-temperature plasma (LTP) post-ionisation. Efficient desorption was reached by covering the TLC plates with activated carbon. Regions of interest can be analysed by spots, by lines or by area. We show the separation of methylxanthines from coffee, tea and cocoa preparations by TLC, with subsequent mass spectrometry imaging (MSI). Using a lateral resolution of 400 mm × 400 mm, allowed the acquisition of 21,895 spectra in 2.4 h (2.5 pixels/s). Further, we demonstrate the possibility of direct mass fragmentation studies and quantification. We mounted the system on an Open LabBot with a theoretical lateral resolution of 12.5 mm and performed the visualisation of ions of interest and the pixel-wise review of mass spectra with our free software RmsiGUI (https://bitbucket.org/lababi/rmsigui). This non-proprietary and modular platform enables the cost-efficient adaption of the system and further development by the community.
关键词： mass spectrometry imaging,thin-layer chromatography,low-temperature plasma,laser desorption,ambient ionisation
更新于2025-09-19 17:13:59
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An approach to analysis of primary amines by a combination of thin‐layer chromatography and matrix‐assisted laser desorption ionization mass spectrometry in conjunction with post‐chromatographic derivatization
摘要： On-spot derivatization has been suggested for the modification of primary amine containing compounds for their analysis by thin-layer chromatography hyphenated with matrix-assisted laser desorption ionization mass spectrometry. The proposed approach was based on post-chromatographic treatment of separated analytes inside the chromatographic zones on the thin-layer chromatography plates by tris(2,6-dimethoxyphenyl)methilium reagent. The derivatives, containing permanent positive charge, reveal exceptionally intense peaks of their cationic moieties and high signal/noise ratio in mass spectra recorded directly from the plates. The method was tested on a series of aliphatic, aromatic, and amine-containing pharmaceuticals.
关键词： thin-layer chromatography,mass spectrometry,primary amines,matrix-assisted laser desorption/ionization,derivatization
更新于2025-09-19 17:13:59
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Effect of Drying on Lettuce leaves using Indirect Solar Dryer Assisted with Photovoltaic Cells and Thermal Energy Storage
摘要： The thin layer drying behavior of lettuce leaves was investigated using an indirect pilot solar dryer with thermal energy storage in water, equipped with solar collectors and photovoltaic cells. The drying procedure consisted of shredded lettuce leaves, temperature ≤ 52 °C, airspeed, 1.0 m?s?1, and process time ~10.0 h. Fifteen drying models were adjusted to the experimental data obtained; three models with maximum values of coefficient of determination (R2)—Page, Midilli, and Kucuk, and Weibull Distribution, whose values of R2 ≥ 0.998, and other statistical parameters, χ2, SSE, and RMSE values closer to zero were chosen. The initial browning index BI = 120.5 ± 0.7 decreased compared to the dry sample BI = 78.99 ± 0.5, with chromatic coordinate degradations a* and b*; but not the luminosity L*; where ΔE = 8.26; whose meaning is that the dry sample is a “more opaque brownish color” due to the difference in the chroma ΔC = 6.65, and with a change from the yellow‐green to yellow‐red zone, and a difference in hue angle, Δh° = 14.27, between the fresh and the dried sample. Deff values for shredded lettuce leaves were 1.8 × 10?9 m2 s?1 for values ≤ 52 °C.
关键词： solar drying,lettuce leaves,mathematical modeling,thin layer drying
更新于2025-09-19 17:13:59
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An Improved Design and Versatile New Lamination Fabrication Method for Twin Electrode Thin Layer Cells Utilizing Track-Etch Membranes
摘要： Reported here are laminated membrane electrodes, an improved design and more advantageous method of fabrication for previously reported thin layer cell electrode systems developed on track-etch membranes. The laminated membrane approach potentially further improves flow resistance by dramatically reducing the surface area to volume ratio, but also produces a cohesive device that can be more readily applied to a broad range of applications. In addition, this new fabrication method was implemented in a scalable, commercial process and resulting product demonstrations indicate that volume manufacturing is feasible. Characterization of laminated membrane electrodes reveal redox cycling amplification factors as high as 30 with linear responses to variable concentrations of redox couple. These performance characteristics are shown to be comparable to similar generator-collector systems fabricated through much more laborious laboratory methods. This combination of added versatility, cost-reduced fabrication and exceptional performance clearly reveals unrealized potential of track-etch membrane approaches and boosts their candidacy as powerful new options for generator-collector electrode systems.
关键词： membrane,thin layer cell,redox cycling,generator-collector electrodes,microfabrication
更新于2025-09-10 09:29:36
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Crystal Structure Characterization of Thin Layer Zinc Oxide
摘要： In this research the characterization of the crystal structure of a thin layer of ZnO (zinc oxide) were synthesized by sol - gel method and spin coating deposited on a glass substrate. The samples were divided into three sol concentrations of 0.1, 0.3, 0.5 Molar and two deposition temperature is 350 °C, and 550 °C. UV-Vis. spectrophotometer results showed that in the spectrum of visible light (wavelength range 300-800 nm) has a transmittance value of which increases with increasing concentration and temperature deposition of zinc oxide, otherwise the value of the absorption and the band gap energy decreases with temperature. The transmittances value of the highest and lowest absorption was 93.5% and 0.03 is at a concentration of 0.1 M and zinc oxide deposition temperature of 550 °C, with a value of band gap energy of 2.98 eV. The XRD results showed that the zinc oxide crystal orientation in the field of 013 with a crystal grain size 14.4472 nm. SEM results showed the surface morphology of zinc oxide such as rod-like.
关键词： ZnO,sol-gel method,thin layer,crystal structure,optical properties,spin coating
更新于2025-09-10 09:29:36