最新刊期
卷 32 ， 期 3 ， 2011
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Preparation and Oxygen-sensing Properties of Ruthenium(Ⅱ) Complex as Optical Oxygen-sensing Material
摘要：An oxygen-sensing optical material based on Ruthenium(Ⅱ) complex grafted to the mesoporous MCM-41 (Ru-pyttz-MCM-41) was synthesized and characterized by infrared absorption spectra (IR) and small-angle X-ray diffraction (SAXRD). The study of luminescence intensity quenching behavior upon various oxygen concentrations indicate that the fluorescence intensity of Ru-pyttz-MCM-41 obviously decrease with the increased oxygen concentrations. The oxygen sensing properties were investigated: good sensitivity and a short response time of 5 s were obtained for Ru-pyttz-MCM-41 , making it promising in detecting oxygen concentration in the field of environmental monitoring and biochemistry.关键词：Ru(Ⅱ) complex;mesostructured molecular sieves;optical oxygen-sensing118|100|1更新时间：2020-08-12 - 摘要：The ZnO nanowires grown via hydrothermal method were modified by Ag with different concentration in solution. The morphology, photoluminescence property, photoresponse of the ZnO nanowire were stu-died. The results exhibited that the intensity of photoluminescence decreases with the increased Ag concentration. The photoresponses of as-grown and modified by Ag of 10 mmol/L nanowires were tested and compared. The responsivity of Ag modified ZnO nanowire was 4.6 mA/W at 380 nm. This value was 75 times larger than that of the as-grown one. The results indicated that photoresponse property of ZnO nanowires can be effectively improved by Ag modifying.关键词：ZnO nanowire;Ag modified;photoresponse112|152|0更新时间：2020-08-12
- 摘要：Eight terbium complexes have been synthesized by using p-bromine-benzoic acid, p-iodin-benzoic acid as the first ligand and 2,4,6-tris-(2-pyridyl)-s-triazine (TPTZ) as the second ligand. The ligands and coordination compounds are studied by IR spectra, UV spectra, fluorescence excitation and emission spectra. The results showed that all the complexes are non-electrolytes. P-bromine-benzoic acid or p-iodin-benzoic acid is bounded with Tb(Ⅲ) through oxygen atoms and 2,4,6-tris-(2-pyridyl)-s-triazine is bounded to Tb(Ⅲ) through three nitrogen atoms. Fluorescence emission spectra indicated that the intensity of terbium complexes of p-bromine-benzoic acid is stronger than those of p-iodine-benzoic acid. The fluorescence intensity of terbium complexes are enhanced by introducing La3+ and Gd3+ ions,respectively. We also find that when n(Tb) ∶ n(Ln)=1 ∶ 1(Ln=La,Gd,Y), the fluorescence emission intensity of Tb0.5La0.5(P-BrBA)3(TPTZ)·2H2O, Tb0.5Gd0.5(P-BrBA)3(TPTZ)·2H2O and Tb0.5Y0.5(P-BrBA)3(TPTZ)·2H2O gradually decrease. The fluorescence emission intensity sequence of Tb (Ⅲ) with p-iodin-benzoic acid and TPTZ complexes are similar with the Tb (Ⅲ) with p-bromine-benzoic acid and TPTZ complexes. The 5D4 energy of Tb3+ ion is 20 430 cm-1, and 21 277 cm-1 for the triplet energy of TPTZ. The triplet energy of TPTZ is higher than the excitation energy of Tb3+ion, thus the absorbing energy of TPTZ can effectively transferred to Tb3+ ion, and producing a characteristic emission spectrum. Some complexes of non-fluorescence rare earth can also absorb the triplet energies of the ligands, and then transfer them to Tb3+ , in this way the fluorescence intensity is enhanced.关键词：p-bromine-benzoic acid;p-iodin-benzoic acid;2;4;6-tris-(2-pyridyl)-s-riazine;terbium complexes107|14|1更新时间：2020-08-12
- 摘要：The CdS nanocryticles doped silica xerogels were prepared by using the sol-gel method,where tetraethoxysilane (TEOS) was employed as the main precursor and cadmium nitrate,thiourea as start materials. The X-ray diffraction pattern indicated that silica xerogels are noncrystalline structure and the mean diameter of the CdS particles is 5.1 nm. The PL emission spectrum of the undoped silica xerogels showed weak emission peaked at 460 nm that could be attributed to the intrinsic defect states of silica xerogel. For 0.5% CdS-doped samples, the photoluminescence intensity reached maximum. The PL excitation spectra of undoped silica xerogel show that only one peak at 350 nm is observed. For CdS-doped samples, a new peak at 380 nm is observed, which could be attribute to the doping CdS quantum dots.关键词：silica xerogels;photoluminescence;CdS nanoparticles;Sol-Gel110|8|0更新时间：2020-08-12
- 摘要：Photoluminescence (PL) of polyimide (PI) thin films irradiated by xenon lamp, electroluminescence (EL) of PI thin films irradiated by xenon lamp under high DC high electric fields and their XRD patterns,absorption spectra were measured. The PL intensity shows an exponential decay with the measuring time. The EL intensity shows exponential increase with electric field. After irradiated 39 h, the pre-breakdown electric field of PI is about 2.56 MV/cm, lower than 2.8 MV/cm before irradiation. Both spectra EL and PL spectra consist peaks near 320,395,443,585,656,752 nm. As the irradiation time becomes longer, PL intensity increases obviously and decays more lowly. PL spectra peaks shift to longer wavelength. And the maximum of absorption wavelength appears red shift. As the applied electric field becomes higher, the EL spectra have fewer peaks and EL peaks appears blue shift. The energy gap of PI was calculated according to the spectral absorption, the value is about 2.76 eV, lower than the value (3.14 eV),calculated according to the PL spectra. These results are likely due to integrated effect of photo-aging and electric aging.关键词：polyimide;photoluminescence;electroluminescence;absorption edge113|10|1更新时间：2020-08-12
- 摘要：Fluoride upconversion luminescent ultrafine powder was synthesized successfully by the hydrothermal method. Comparing with the high-temperature solid-state reaction method, the sample from the hydrothermal method is more suitable for the application in optoelectronic detection because of the better spatial resolution. The physical mechanism of the Er3+-doped fluoride 1 550 nm upconversion luminescence was discussed. The influences of Er3+ dopant concentration, reaction temperature and reaction time were studied.关键词：Er3+-doped fluoride;1 550 nm upconversion luminescence;ultrafine powder;hydrothermal method118|15|2更新时间：2020-08-12
- 摘要：Na2SO4 ∶ Mn phosphors were prepared by heating pure natural thenardite with MnCl2 at 900 ℃ for 20 min in air. Their photoluminescence (PL) spectra were investigated under vacuum ultraviolet (VUV) at room temperature. The results show the emission spectrum under 172 nm excitation consists of a broad band with a peak at 592 nm,which can be attributed to the 4T1→6A1 transition in the 3d shell of Mn2+. The excitation spectrum obtained by monitoring the red luminescence divides into two parts: absorption bands of Mn2+(191 nm and 275 nm) and host absorption bands (165 nm and 233 nm).The relative emission efficiency increase with the mass fraction of MnCl2 in 0.1%~0.4% range,and the concentration quenching occurs at 0.3% Mn contents.关键词：thenardite;Na2SO4 ∶ Mn;photoluminescence;vacuum ultraviolet excitation;concentration quenching104|10|1更新时间：2020-08-12
- 摘要：(Li, Cu)-doped ZnO thin films were prepared on the n-type Si (100) substrate by means of sol-gel process. The structure, surface morphology and photoluminescence properties of the ZnO films were investigated. The results show that all of ZnO thin film samples have strong c-axis preferred orientation. The visible luminescence intensity of Li-doped ZnO films increases with the dopant concentration. The visible light emission can be attributed to the incorporation of transitions derived from the singly ionized oxygen vacancy to the top of valence band and LiZn acceptor states. Similarly, the yellow-green emission might be due to the incorporation of transitions derived from the singly ionized oxygen vacancy to the top of valence band and CuZn acceptor states. With the increase of Cu dopant concentration,the transition of singly ionized oxygen vacancy to CuZn acceptor states plays a dominative role.关键词：ZnO thin films;(Li;Cu) doping;photoluminescence109|96|2更新时间：2020-08-12
- 摘要：N,N'-bi(L-aminosuccinic amine)-perylene-3,4; 9,10-tetracarboxylic diimide(PTCDA)was synthesized and characterized. The UV-vis absorbance of PTCDA(10-5 mol/L) solution is sensitive to pH value over a wide range from 10.75 to 3.97, and a gradual decrease with absorption intensity was observed as pH ranging from 10.75 to 4.73.A rapid decline in fluorescence intensity was found with pH varing from 10.75 to 9.66,while a trady reduction in fluorescence intensity was found upon a fall in pH from 9.66 to 5.12. The fluorescence of PTCDA was quenched when the pH was inferior to 5.12. The change of fluorescence spectrum and absorption spectrum can be attributed to the π-π stacking produced by pH value.This indicates PTCDA can be used as a pH probe in water solution.关键词：perylene diimide derivative;water-soluble;pH probe;absorption spectrum;fluorescence spectrum108|154|8更新时间：2020-08-12
- 摘要：A series of new green-emitting phosphors, Eu2+-activated Ca5-xEux(SiO4)2F2 were synthesized at 1 223 K by conventional high-temperature solid-state reactions under reductive atmosphere. And the photoluminescence excitation, diffuse reflectance and emission spectra, concentration quenching process, temperature dependence of luminescence and lifetime of phosphors were systematically investigated. The excitation spectrum shows that Ca5(SiO4)2F2 ∶ Eu2+ can be efficiently excited by the incident lights of 250~440 nm, perfectly matching with the emissions wavelength of near-UV LEDs. The emission intensity is influenced by the Eu2+ content, and the optimal doping mole fraction is about 0.15. The concentration quenching mechanism was verified as dipole-dipole interaction and the value of the critical transfer distance was calculated as 1.5 nm. The temperature dependent emission spectra in the temperature range of 10~450 K show that the emission intensity at 450 K is 35% of the emission intensity at 10 K. At room temperature, the lifetimes of Eu2+ ions in Ca4.85Eu0.15(SiO4)2F2 phosphors are determined to be 1.78 μs and 7.79 μs, respectively. All of these indicate that Ca5(SiO4)2F2 ∶ Eu2+ is a promising green phosphor candidate for phosphor-converted white LEDs.关键词：white LED;alkali earth chlorosilicates;rare earth105|11|2更新时间：2020-08-12
- 摘要：p-i-n GaN based avalanche UV photodetectors were fabricated and characterized. Dark current of the device is as low as 0.05 nA at the reverse bias of 5 V and ＜0.5 nA at 20 V. Repeatable photocurrent avalanche gain, began at around 80 V and grew up to a peak of 120 at about 85 V, demonstrating a good material quality. C-V mea-surement was used to determine carrier distribution and depletion information, and it showed that p-layer fully depleted at reverse bias of about 15 V, resulting in a hole concentration of 1.9×1017 cm-3. The relative low hole concentration might lead to a weak confinement of electrical field and an increase in the operating voltage of the device. Photocurrent spectroscopy under various bias was also measured and exhibited obvious Franz-Keldysh effect.关键词：UV photodetector;avalanche;impact ionization113|166|1更新时间：2020-08-12
- 摘要：The band structure and spontaneous emission spectra of the InGaN/GaN multiple quantum well (MQW) structures considering the polarization effect were systematically analyzed employing a newly deve-loped theoretical model based on the k·p theory. Numerical results show that the square potential profile of conduction band and valence band change to triangle due to the polarization effect. And polarization-induced electrostatic field makes the bandgap of InGaN/GaN MQW structure narrow,which results in the red shift of peak emission wavelength. In addition, the emission efficiency of InGaN/GaN MQW structure reduces because the polarization effect separates the distribution of electrons and holes. Furthermore, the red shift of the peak emission wavelength induced by the polarization effect is enhanced under the condition of more In content in well layers or deeper well width for the InGaN/GaN MQW structures.关键词：InGaN/GaN;polarization effect;multiple quantum well;spontaneous emission spectra149|12|1更新时间：2020-08-12
- 摘要：Highly c-axis oriented n-type ZnO films were grown on the p-type fresstanding diamond(FSD) substrates by radio-frequency (RF) magnetron sputtering method. The effects of the sputtering power on the pro-perties of ZnO films were studied. Current-voltage (I-V) characteristics of the ZnO/diamond heterojunction were examined by a semiconductor characterization system and the results showed a distinct rectifying characteristics with a turn-on voltage of about 1.6 V. The ZnO/diamond heterojunction diode was also used for ultraviolet(UV) detector application and the detector showed a significant discrimination between the UV light and the visible light under reverse bias conditions.关键词：freestanding diamond;ZnO;detector;heterojunction148|9|2更新时间：2020-08-12
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The Adhesive Performance and Field Emission Performance of Carbon Nano-tube/Bentonite Composite Film
摘要：Uniformity and stability of field emission are seriously influenced by adhesive properties between carbon nanotubes(CNT) and substrate. CNT/bentonite(bentonite power, BP) compound film are fabricated. Interlayer created by CNT and the basement decrease potential barrier of CNT film by adding BP, and thus contact performance is improved. Test shows that adhesive performance of CNT/BP film is enhanced. More-over, uniformity and stability of field emission increase distinctly.107|9|0更新时间：2020-08-12 - 摘要：InGaAsSb/ AlGaAsSb multi-quantum-well(MQWs) were grown by molecular beam epitaxy. The X-ray diffraction pattern presents multi-levels of satellite peaks, which indicate a good interface and excellent crystal quality. Meanwhile, photoluminescence shows the emission wavelength at room temperature covers 1.6~2.3 μm with varing In compositions in InGaAsSb/ AlGaAsSb MQWs.关键词：InGaAsSb/AlGaAsSb;MQWs;MBE140|12|1更新时间：2020-08-12
- 摘要：A novel type of linear bipolar compound, 2,7-di(2-thienyl)fluoren-9-one (DTFO), was synthesized via Suzuki coupling reaction and was employed as a red-light organic electroluminescence material. The structure and electronic properties of DTFO were simulated; chemical structure of DTFO was identified. Moreover, its photo physical properties, thermal stability and film formability were characterized in detail. The analog results indicate that the structure of DTFO is nearly flat and linear structure with alternating conjugate. In photoluminescence spectra, DTFO exhibits a maximum emission peak at 616 nm, which emits strong red light. In addition, both the thermal stability and film formability are excellent for this novel material.关键词：OLED;red-light material;fluorenone;thiophene;donor-acceptor135|21|3更新时间：2020-08-12
- 摘要：Al doped ZnO (AZO) thin film is prepared by the double electron beam co-evaporation with an ion-assisted deposition technique. The AZO film shows a carrier density of 4.39×1020 cm-3 and an electron mobility of 15 cm2·V-1·s-1, respectively. The AZO thin film has a work function of 5.05 eV, and shows an average visible spectral transmittance of 85.5%. OLED based on AZO anode exhibits a maximum luminance of 192 400 cd/m2 and a maximum current efficiency of 83.5 cd/A, which indicates that AZO films can be a promising anode material for organic EL devices.关键词：transparent conducting oxide;AZO;phosphorescent;organic light-emitting device121|8|1更新时间：2020-08-12
- 摘要：In human physical conditions, the binding reaction between cefpirome sulfate (CPS) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy, synchronous fluorescence spectroscopy and resonance light scattering (RLS) at different temperatures. Results showed that both fluorescence and RLS of BSA reduced with the increased concentration of CPS, and the effect between CPS and BSA was static fluorescence quenching process with Frester spectroscopy energy transfer. The scope of apparent binding constants (Ka) was ~104; the corresponding binding site value (n) in the binary systems was 1; the binding distances (r) were much smaller than 7 nm and the primary binding site for CPS was located at site Ⅰ in sub-domain ⅡA of BSA. Besides, the electrostatic attraction plays an important role in the conjugation reaction of BSA and CPS. The values of Hills coefficients were less than 1, which indicated that there was some negative cooperative effect. Studies utilizing synchronous spectra showed that the conjugation reaction between CPS and BSA would affect the conformation of BSA, leading to the polarity around BSA strengthened and the hydrophobicity weakened.关键词：bovine serum albumin;cefpirome sulfate;conjugation reaction;luminescence mechanism115|9|6更新时间：2020-08-12
- 摘要：Excitation-emission matrix (EEM) technology was used to study fluorescence properties of acrylonitrile-butadiene-styrene (ABS) resin wastewater with its variation trend in the treatment process. The effect of different voltage for the degradation of aromatic compounds was studied significantly. The results show that two fluorescence center of ABS resin wastewater load at the wavelength of λex/λem=225/340 nm (Peak A) and λex/λem=275/340 nm (Peak B), respectively, and the ratio of IPeakA/IPeakB is 8.1. A higher chemical oxygen demand (COD) and total fluorescence intensity removal efficiencies under a higher voltage, and the aromatic compounds of ABS wastewater can be decomposed efficiently. Under the different voltage, there is a good linear correlation for COD and total fluorescence intensity removal efficiencies. And their correlation coefficients are all over than 0.96, therefore the decomposition efficiency of aromatic compounds for ABS wastewater can be determined and analyzed efficiently using EEM technology.关键词：spectroscopy;ABS wastewater;three-phase three-dimensional electrode reactor;excitation-emission matrix90|122|0更新时间：2020-08-12
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