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Characterization and Photoluminescence Property of a New Eu <sup>3+</sup> -doped Phosphor of the K <sub/>2</sub> [Al(B <sub/>5</sub> O <sub/>10</sub> )] Prepared by Precursor Method
摘要： A new phosphor of the K2[Al(B5O10)]:Eu3+ was prepared by annealing of the as-prepared of the precursor of K2[Al(B5O10)]·4H2O:Eu3+ at 300–400 °C, and which has been synthesized under facile hydrothermal conditions. All the samples were characterized by the EDS, XRD, FT-IR, and SEM. A systematic study on their luminescent properties has been performed by the PL and PLE. A series of influencing factors on the luminescent properties were also investigated. The PL and PLE studies reveal that the phosphor of K2[Al(B5O10)]:Eu3+ with optimal luminescent intensity and higher red-orange ratio were obtained by sintering the precursor at 400 °C for 5.5 h, with 9% doping concentration, which suggests that it might as a potential application of the light display systems.
关键词： Precursor method,Luminescent property,Eu3+ doped phosphor,Aluminoborate
更新于2025-09-23 15:22:29
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Synthesis, Crystal Structure, and Properties of a Zn(II) Coordination Polymer Based on a Difunctional Ligand Containing Triazolyl and Carboxyl Groups
摘要： A new compound, namely, [Zn(L)2]n (1) was obtained by the reaction of 2-methyl-4-(4H-1,2,4-triazol-4-yl) benzoic acid (HL) with ZnSO4·7H2O, and the compound was characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), and thermogravimetric analysis. The linear HL ligands were deprotonated to be L? anions and act as two-connectors to link Zn2+ to form a two-dimensional (2D) lay structure with (4, 4) topology. The large vacancy of 2D framework allows another layer structure to interpenetrate, resulting in the formation of 2D + 2D → 2D parallel interpenetration in 1. The weak interactions, such as hydrogen bonding and π–π stacking interactions, connect the adjacent 2D layers into a three-dimensional (3D) coordination polymer. The solid-state UV-visible spectroscopy and luminescent property have also been studied.
关键词： supramolecular polymer,spectral property,crystal structure
更新于2025-09-23 15:22:29
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Pyroelectric Property of Binary Nitrides (AlN, GaN and InN)
摘要： The pyroelectric (PY) property of binary nitrides (AlN, GaN and InN) has been explored theoretically. The spontaneous and piezoelectric (PZ) polarization modifies the thermal conductivity of these nitrides. The thermal conductivities as a function of temperature including and excluding the polarization mechanism (kp and k) predict a transition temperature (T p) between primary and secondary PY effects. Below T p, thermal conductivity kp is lower than k. This is due to negative thermal expansion in binary nitrides. Above T p, kp is greater than k. kp is significantly contributed by PZ polarization due to thermal expansion which is the reason of secondary PY effect. The transition temperature T p for AlN, GaN and InN has been predicted as 100 K, 70 K and 60 K, respectively. This study suggests that thermal conductivity study can reveal PY property in semiconductors.
关键词： Thermal expansion,Thermal property,Pyroelectric coefficient,III–V Binary nitride,Built-in polarization
更新于2025-09-23 15:22:29
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Epitaxial Growth of Orthorhombic GaFeO3 Thin Films on SrTiO3 (111) Substrates by Simple Sol-Gel Method
摘要： A Sol-gel method assisted with spin-coating has been successfully used to grow orthorhombic GaFeO3 epitaxial films on SrTiO3 (111) substrates for the first time. The film with Pna21 crystal structure has been grown along the c-axis. The rocking curve of (004) reflection shows that the Full-Width at Half-Maximum (FWHM) value could be determined to be 0.230°, indicating good single crystallinity and high quality. X-ray Φ scan reveals a three-fold symmetry of the substrate and a six-fold symmetry of the film, respectively. The in-plane domains rotate 60° from each other in the film. Uniform film with dense structure, columnar grains with similar grain size was obtained. The thickness of the film was evaluated to be ~170 nm. The roughness value (RMS) measured by AFM was 4.5 nm, revealing a flat film. The in-plane Magnetization versus Magnetic field (M-H) curve at 5 K performs a typical ferri- or ferromagnetic hysteresis loop with a saturated magnetization (Ms) value of 136 emu/cm3. The Curie temperature could be determined to be 174 K. Compared to Pulsed Laser Deposition (PLD), the sol-gel method can prepare large area films with low cost. These new films show promising applications in multiferroic devices.
关键词： GaFeO3 film,magnetic property,sol-gel method,multi-domain structure,epitaxial growth
更新于2025-09-23 15:22:29
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Optically transparent, organosoluble poly(ether-amide)s bearing triptycene unit; synthesis and characterization
摘要： Aromatic polyamides are famous high performance polymeric materials for their excellent thermal, mechanical, electrical properties, which now a days became a dominant platform for modern polymer chemistry area. Triptycene unit like structures in polymer directly affects the physiochemical properties of polymer, thus polyamides especially with triptycene unit in their backbone with aryl ether linkage imparts combination of properties such as better solubility, melts processing characteristics, and better thermal stability in contrast with those of polymers without an aryl-ether linkageNew triptycene-containing bis(ether amine), 1,4-bis(4-aminophenoxy), 2, 3-benzotriptycene (4a) was synthesized from nucleophilic displacement reactions of P-fluoronitrobenzene with 1,4-dihydroxytriptycene, followed by reduction, and elucidated by FTIR, 1 H, 13 C NMR spectroscopy and HRMS. A series of new polyamides containing pendant triptycene group and flexibilizing ether linkages was synthesized by polycondensation of diamine with commercially available aromatic diacischlorides viz., terephthalylchloride (TPC), isophthalylchloride (IPC) and varying molar mixture of TPC and IPC accordingly. Synthesized Poly(ether-amide)s were found soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, DMF, DMAc, DMSO also could be cast into excellent transperent thin films. Inherent viscosities of polyamides were in the range 0.44–0.57 dL/g. Polyamides exhibited initial decomposition temperature (Ti), glass transition temperatures (Tg) and temperature at 10% wt loss (t10), which was determined by TGA were noted in the range 212 (cid:1)C–305 (cid:1)C, 295 (cid:1)C –309 (cid:1)C and 587 (cid:1)C–631 (cid:1)C respectively with 24%–54% char yeild at 900 (cid:1)C under nitrogen atmosphere, indicating its better thermal stability and moderate glass transition temperature.
关键词： inherent viscosity,optical property,Polyamides,triptycene unit,thermal analysis,structure-property relationship
更新于2025-09-23 15:21:21
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Crosslinked Organosilicon-Acrylate Copolymer Moisture Barrier Thin Film Fabricated by Initiated Chemical Vapor Deposition (iCVD)
摘要： Crosslinked organosilicon-acrylate copolymer thin film with desired chemical composition was successfully fabricated by a simply modified initiated chemical vapor deposition (iCVD) process. Unlike the conventional iCVD copolymerization process, in our novel process, comonomers were injected together as one gas phase into the polymerization chamber from miscible liquid comonomer mixture. 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (V4D4) and cyclohexyl methacrylate (CHMA) were used as the comonomers and tert-butyl peroxide was used as the initiator. From Fourier transform infrared (FTIR) spectra and solvent resistance test, we clearly confirmed that the crosslinked copolymer thin film with desired chemical composition could be obtained by controlling only the mixing ratio of liquid comonomers. It is expected that crosslinkable V4D4 organosilicon moiety provides hydrophobic moisture barrier property and CHMA acrylate moiety provides mechanical flexibility and better adhesion. We observed a certain level of moisture blocking capability of the copolymer thin film, implying potential application of the crosslinked organosilicon-acrylate copolymer thin film as flexible polymer buffer layer in organic/inorganic or metal oxide hybrid moisture barrier for flexible display or electronic devices.
关键词： moisture barrier property,copolymer thin film,initiated chemical vapor deposition (iCVD),cyclohexyl methacrylate (CHMA),2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (V4D4)
更新于2025-09-23 15:21:21
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Tailor-made ultra-crystalline, high molecular weight poly(ε-caprolactone) films with improved oxygen gas barrier and optical properties: a facile and scalable approach
摘要： The work presents a facile and scalable approach for fabricating tailor-made ultra-crystalline, high molecular weight biodegradable polymer poly(ε-caprolactone) [PCL] through ring-opening polymerization. Linear homopolymer of PCL were fabricated by tuning the molar ratio of monomer: initiator: catalyst in associated with organometallic catalyst (tin octoate) and a non-toxic and structurally symmetric initiator ethylene glycol (EG). High molecular weight PCL homopolymer formation with molecular weight higher than 90000 Da was examined by FTIR, NMR and GPC. The ultra-crystalline characteristics (percent crystallinity, %Xc >70%) and unique crystal morphology of PCL were thoroughly scrutinized using DSC, XRD, HRTEM, SAED patterns and POM analysis. The developed protocol for the solvent-free technology allows high conversion ~99% at lowest possible reaction time of 1 h suggesting it a cost effective process, which is scalable to larger volume (5000 mL) without compromising the final product properties. The fabricated ultra-crystalline, high molecular weight PCL films showed good oxygen barrier property (~ 197 cm3 mm-1 day-1), surface free energy (133.7 mN/m) and optical transparency, recommending its niche in envisioned applications like low temperature flexible packaging and biomedical field.
关键词： Poly(ε-caprolactone) [PCL],Crystallinity,Oxygen barrier property
更新于2025-09-23 15:21:21
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Highly Sensitive Room-Temperature Sensor Based on Nanostructured K2W7O22 for Application in the Non-Invasive Diagnosis of Diabetes
摘要： Diabetes is one of the most rapidly-growing chronic diseases in the world. Acetone, a volatile organic compound in exhaled breath, shows a positive correlation with blood glucose and has proven to be a biomarker for type-1 diabetes. Measuring the level of acetone in exhaled breath can provide a non-invasive, low risk of infection, low cost, and convenient way to monitor the health condition of diabetics. There has been continuous demand for the improvement of this non-invasive, sensitive sensor system to provide a fast and real-time electronic readout of blood glucose levels. A novel nanostructured K2W7O22 has been recently used to test acetone with concentration from 0 parts-per-million (ppm) to 50 ppm at room temperature. The results revealed that a K2W7O22 sensor shows a sensitive response to acetone, but the detection limit is not ideal due to the limitations of the detection system of the device. In this paper, we report a K2W7O22 sensor with an improved sensitivity and detection limit by using an optimized circuit to minimize the electronic noise and increase the signal to noise ratio for the purpose of weak signal detection while the concentration of acetone is very low.
关键词： non-invasive,biomarker,ferroelectric property,blood glucose,volatile organic compound,acetone,nanostructured K2W7O22,diabetes
更新于2025-09-23 15:21:21
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Time Dependent Facile Hydrothermal Synthesis of TiO2 Nanorods and their Photoelectrochemical Applications
摘要： In the present investigation, we report facile hydrothermal synthesis of TiO2 nanorods with high density rutile phase on Transparent Conducting Oxide (TCO) for enhanced solar cell application. The structural, optical, morphological, compositional and electrochemical properties are investigated by detailed XRD, UV-Vis-NIR spectrophotometer, FESEM, TEM, EDAX, XPS and photoelectrochemical studies. It is demonstrated that, the deposited TiO2 thin film shows pure rutile phase with tetragonal crystal structure. Optical spectra showed strong light absorption in UV region and FESEM images confirm the time dependent growth of TiO2 nanorods. EDAX and XPS Spectra confirm the formation of pure TiO2 nanorods. Photoelectrochemical performance with respect to time dependent growth of TiO2 nanorods showed highest photoconversion efficiency = 5.1%.
关键词： Hydrothermal synthesis,Photoelectrochemical cell property,Single crystalline,Photoconversion efficiency,TiO2 nanorods,Transparent conducting oxide (TCO)
更新于2025-09-23 15:21:21
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The transmittance and sheet resistance of chemically and heat reduced graphene oxide film
摘要： The graphene oxide (GO) sheets were prepared from Hummer’s method. The reduced process is important to graphene related materials for widely functional use in many photo-electric fields. Chemically and heat reduced treatment are carried out in this research and the electrical and optical properties of reduced GO films are measured. The size of GO sheets was examined by transmission electron microscopy with a size of about 5–6 μm. The chemically converted graphene (CCG) film are made by spin coating method. We used different GO concentration and different spin coating times to investigate the properties of graphene transparent conductive films. As the decrease of the GO concentration of solution and the times of spin coating, the transmittance is higher. The electrical property of the mixing of GO and CCG is more stable than the GO sheets only, this is discussed in this research and it is cause by the stacking condition of sheets. The conductivity of reduced graphene oxide film come from GO is lower than that come from CCG, we suppose that is because that the overlapping is less (i.e. film-forming ability) in the former, the transmittance and sheet resistance are 56 T% and 50 kohm/sq.
关键词： Graphene oxide,Electrical property,Liquid-phase exfoliation,Transparent conductive films,Chemical reduced graphene oxide
更新于2025-09-23 15:21:21