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Investigations of nano-crystalline Sr0.5Ba0.5Nb2O6 and bulk ceramics synthesized by a polymerization method using PEG400
摘要： Nano-crystalline Sr0.5Ba0.5Nb2O6 was synthesized by a one-pot method using PEG400 and citric acid. Calcination of the (Sr,Ba,Nb)-gel at 600 °C leads to Sr0.5Ba0.5Nb2O6 with a crystallite size of 24(2) nm and a specific surface area of 38.5(10) m2 g?1. Sintering up to 1325 °C leads to ceramics with globular or irregular-shaped grains and average grain sizes between 1.3 and 2.4 μm, whereas higher temperatures lead to a rod-like microstructure. The indirect allowed optical band gap varies between 3.70(5) and 3.29(5) eV. Dielectric measurements show a diffuse phase transition and weak relaxor properties. The maximum of the permittivity occurs between 116 and 147 °C. The frequency dependence of the impedance can be well described by one or two RC-circuits depending on sintering temperature. The melting temperature is determined as 1506(7) °C with ΔHf = 140(20) kJ mol?1. The average linear thermal expansion coefficient is found to be 10.5(5)?10?6 K?1.
关键词： Nano-particle,Strontium barium niobate,Band-gap,Dielectric permittivity,Tungsten bronze
更新于2025-09-23 15:21:01
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Surface plasmon-enhanced solution-processed phosphorescent organic light-emitting diodes by incorporating gold nanoparticles
摘要： Organic light-emitting diodes (OLEDs) have attracted increasing attention due to their superiority as high quality displays and energy-saving lighting. However, improving the efficiency of solution-processed devices especially based on blue emitter remains a challenge. Excitation of surface plasmons on metallic nanoparticles has potential for increasing the absorption and emission from optoelectronic devices. We demonstrate here that the incorporation of gold nano particles (GNPs) in the hole injection layer of poly(3,4-ethylene dioxythiophene):polystyrene sulfonic acid with an appropriate size and doping concentration can greatly enhance the efficiency OLED device especially at higher voltage. Apparently, the spectral of the multiple plasmon resonances of the GNPs and the luminescence of the emitting materials significantly overlap with each other. At 1000?cd/m2 for example, the power efficiency of a studied green device is increased from 29.0 to 36.2 lm/W1, an increment of 24.8%, and the maximum brightness improved from 21,550 to 27,810?cd/m2, an increment of 29.1%, as 2 wt% of a 12 nm GNP is incorporated. Remarkably, designed blue OLED also exhibited an increment of 50% and 35% in power efficacy at 100 and 1,000 cd/m2, respectively, for same device structure. The reason why the enhancement is marked may be attributed to a strong absorption of the short-wavelength emission from the device by the gold nano particles, which in turn initiates a strong surface plasmon resonance effect, leading to a high device efficiency.
关键词： OLED,surface plasmon resonance effect,efficiency,gold nano particle,size effect
更新于2025-09-23 15:19:57
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AIP Conference Proceedings [AIP Publishing ADVANCES IN BASIC SCIENCE (ICABS 2019) - Bahal, India (7–9 February 2019)] ADVANCES IN BASIC SCIENCE (ICABS 2019) - Synthesis and characterization of ZnO nano-particles for solar cell application by the cost effective co-precipitation method without any surfactants
摘要： The energy problem is the most fascinating problem in this world because the way of success of every country is depending upon the development of the low cost, well-ordered and high efficiency energy source devices.There are several research groups are working to develop the devices for renewable energy sources. So we are going to focusour research on solar cells materialsforrenewable energy sources like Zinc Oxide (ZnO). This material ishighly useful for making the heterojunction solar cell as well as window layer.Other hand ZnO is used for 3rd generation/DSSC. In this direction we have synthesized zinc oxide (ZnO) nanoparticles by low cost co-precipitation method without any surfactants. The synthesized ZnO nanoparticles have done the characterizations like X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) to evaluate shape, size, reproducibility and morphology of nanoparticles.
关键词： Solar cell,Doped ZnO,Nano-particle,Zinc Oxide,DSSCs
更新于2025-09-12 10:27:22
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Heteroleptic complexes of silver(I) featuring 4′-hydroxy- and 4′-(2-furyl)-2, 2′:6′, 2″-terpyridine: an easy route to synthesis silver nanoparticles
摘要： New coordination complexes of silver(I) containing triphenylphosphine and 4′-hydroxy-2,2′:6′,2″-terpyridine (tpyOH) or 4?-(2-furyl)-2,2′:6′,2″-terpyridine (ftpy) have been synthesized to afford the new compounds [Ag(tpyOH)(PPh3)](NO3) (1) and [Ag(ftpy)(PPh3)](NO3) (2). In addition, the reaction of silver(I) nitrate with ftpy in the presence of excess of 4,4′-bipyridine (bpy) and NH4PF6 led to the formation of binuclear complex [Ag2(ftpy)2(μ-bpy)](PF6)2 (3). The products have been characterized by elemental analysis, IR, UV-Vis, NMR (1H, 31P) spectroscopy and single crystal X-ray diffraction in the case of 3. The 31P NMR data reveal that the interaction of PPh3 with silver(I) is maintained in solution in 1-2. The crystal structure of 3 shows that each Ag+ ion is coordinated by three N-atoms of ftpy and a nitrogen from the bridging ligand of bpy in a slightly distorted square planar geometry. There are some strong noncovalent interactions of hydrogen bonding and Ag-η2-furyl in the crystal structure, connecting molecules to form a supramolecular network. The thermal decomposition of 1-3 has also been investigated. The thermal stability of all complexes, as determined by thermogravimetric analysis (TGA), are almost the same and they are thermally stable up to 220 oC. The complex 3 was used for the preparation of Ag nanoparticles by simple calcination method at two different temperatures of 400 and 600 ?C resulting in the formation of silver nanoparticles, crystalline in nature with the size of 66 and 52 nm, respectively, using Scherrer’s equation. The nano-sized silver particles have also been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDX).
关键词： Crystal Structure,Thermal Properties,Nano Particle,Silver,Terpyridine
更新于2025-09-09 09:28:46