最新刊期
卷 37 ， 期 3 ， 2016
- 摘要：5,5',6,6'-tetraphenyl-2,2'-bipyrazine (Dbppz) was synthesized by oxidation coupling of two molecules 5,6-diphenyl-2,3-dihydropyrazine which was prepared from ethanediamine and benzil, with lewis acid as catalyst, such as IrCl3·3H2O and boron fluoride ethyl ether. Dbppz shows intense fluorescent emission in the tetrahydrofuran (THF) solution at λmax=400 nm, with photoluminescence (PL) quantum yield of 89% in THF solution and 78% in polystyrene film doped with Dbppz mass fraction of 5%. Non-doped electroluminescence (EL) devices were fabricated with a structure of ITO/HAT-CN(5 nm)/NPB(40 nm)/Dbppz (20 nm)/TmPyPB (40 nm)/LiF(1 nm)/Al(100 nm). It is unexpected that the devices do not show blue electroluminescence (EL) as we expect, but white EL with CIE coordinates of (0.27, 0.33). There are two emission peaks at 415 and 550 nm in EL spectrum. The emission peak at 415 nm is attributed to "the intrinsic emission" of Dbppz and low-energy emission at 550 nm relates to interface-interaction between hole-transporting layer and emission layer. Probably, the exciplex is formed by interaction of donor molecule NPB and acceptor Dbppz, resulting in new low-energy emission and restraining the intrinsic emission of Dbppz. This white device shows maximum external quantum efficiency of 44%, maximum luminance efficiency of 1.04 cd/A and maximum power efficiency of 0.74 lm/W.关键词：5;5';6;6'-tetraphenyl-2;2'-bipyrazine;oxidation coupling;photoluminescence and electroluminescence;white organic light-emitting device143|160|1更新时间：2020-08-12
- 摘要：ZnO nanoparticle has been used as cathode buffer layer (CBL) in organo-lead halide perovskite (PVSK) solar cells to improve device stability against oxygen and moisture. For solution processing procedure, solvents for dissolving ZnO has to be carefully optimized, since solvent penetration during the CBL deposition might cause the decomposition of the PVSK film. Aiming at the development of nano-ZnO inks for using in PVSK solar cells, the current work systematically investigate the dispersibility of nano-ZnO in various polar solvents, including acetone, methanol, ethanol, isopropanol, n-butanol, and a mixture solvent of methanol:n-buthanol (MeOH:n-BuOH, 1:1, v/v), and the influence of such solvent on the UV-Vis absorption and crystalline properties of the underlying PVSK/PCBM film. PVSK solar cells with a device structure of ITO/PEDOT:PSS/PSS/PVSK/PCBM/ZnO/Al were then fabricated and tested. The optimized nano-ZnO ink is found to be MeOH:n-BuOH mixture solvent based (1:1, v/v) with a concentration of 10 mg·mL-1. The current work provides an important guideline for developing CBL inks for PVSK solar cells.关键词：perovskite solar cells;nano-ZnO ink;dispersion solvent;ZnO concentration;device stability146|221|1更新时间：2020-08-12
- 摘要：NaLa0.7(MoO4)2-x(WO4)x:0.3Eu3+ afterglow luminescent materials were synthesized by solid state reaction. The crystal structure and luminescence properties of the samples were characterized by means of X-ray diffraction and photoluminescence spectra. The results show that NaLa0.7(MoO4)2-x(WO4)x:0.3Eu3+ phosphors can be excited efficiently by near-ultraviolet (393 nm) and blue light (462 nm), and the main emission peak is located at 615 nm due to 5D0-7F2 transition of Eu3+ ions. X-ray diffraction pantterns (XRD) show that the phosphors calcinated at 900 ℃ for 8 h were pure NaLa(MoO4)2 crystal phase. The luminescent intensity of NaLa0.7(MoO4)2-x(WO4)x:0.3Eu3+ increases with the increasing of W6+ content, and reaches the maximum when the doping content of W6+(x) is 1. The phenomenon of concentration quenching occurs when W6+ doping concentration is excess. Moreover, the CIE chromaticity (x, y) of NaLa0.7-(MoO4)2-x(WO4)x:0.3Eu3+ excited by 393 nm and 462 nm lights were analyzed. When the doping concentration of W6+(x) is 1, the red chromaticity coordinate of the samples is closer to the Commission International de LEclairage (CIE) chromaticity coordinates.关键词：luminescent material;molybdate/tungstate;rare earths;long afterglow96|47|9更新时间：2020-08-12
- 摘要：Four iridium (Ⅲ) pyrazine complexes 1 [(DFMPPZ)2Ir(pic)], 2 [(DFMPPZ)2IrCl-(PPh3)], 3 [(DFMPPZ)2Ir(CN)(PPh3)], and 4 [(DPPF)2Ir(acac)] were synthesized, where DFMPPZ= 2-(2,4-difluorophenyl)- 3-methylpyrazine, pic=picolinate, Ph=phenyl, acac=acetylacetonate, MDPPF=4,4'-difluoro-5-methyl-2,3- diphenylpyrazine. The complexes were characterized by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Their photophysical properties were investigated by UV-Vis and photoluminescence (PL) spectroscopy. All of these Ir (Ⅲ) complexes show the noticeable absorption peaks from metal-to-ligand charge transfer (MLCT) transitions. The iridium (Ⅲ) complexes 1, 2, 3 and 4 have strong photoluminescence at 528, 536, 535 and 561 nm, respectively. Moreover, the iridium (Ⅲ) complex 4 was utilized as phosphorescence dopant in OLEDs with the structures of ITO/MoO3(1 nm)/CBP(35 nm)/CBP:Ir(15 nm)/TPBi(50 nm)/LiF(1nm)/Al(100 nm). The devices showed yellow emission at 567 nm with a maximum brightness of 32 110 cd·m-2, current efficiency of 32.4 cd·A-1, and power efficiency of 28.2 lm·W-1.关键词：iridium complex;pyrazine;phosphorescent material;OLED109|128|0更新时间：2020-08-12
- 摘要：In order to improve the luminescence efficiency of upconversion nanocrystals, a new strategy to significantly enhance upconversion emission was proposed based on coupling of non-lanthanide ions doping with the growth of an inert shell. As a proof-of-concept experiment, hexagonal NaGdF4:Yb3+/Er3+, NaGdF4 and Li+ ions were chosen as luminescent core, inert shell and non-lanthanide ions, respectively. The results demonstrate that significant enhancement of 39 times from β-NaGdF4:Yb3+/Er3+ nanocrystals is clearly observed under the synergistic effect, which is larger than the sum of separate enhancement from the Li+ doping and growth of an inert shell. By means of a series of experimental studies, the optimal doping mole fraction of Li+ ions in the core-shell nanocrystals is found to be about 4%. Moreover, the mechanism for the luminescent enhancement of upconversion nanocrystals has been discussed.关键词：non-lanthanide ions doping;core-shell;β-NaGdF4:Yb3+/Er3+;upconversion115|138|1更新时间：2020-08-12
- 摘要：PVDF-templated nanowires were prepared directly through a template infiltration method in the anodic porous alumina (AAO) membranes with the use of nano-confinement effect for the purpose of improving the piezoelectric properties of PVDF. PVDF was dissolved in N, N-dimethylformamide (DMF) in different concentration, and then different solutions were obtained. During this process, the polyvinylpyrrolidone (PVP) acted as a surface modifying agent. The effects of infiltration temperature, concentration of solution and surface modifying agent on the growth of PVDF nanowires were studied. In the meantime, the growth process and mechanism of PVDF nanowires were investigated by FTIR, SEM, XRD, and so on. The results show that the concentration of solution is the main factor that affects the morphology of the nanowires. Moreover, the optimal morphology is obtained when the concentration is 0.10 g/mL, with an average length of 50 μm and an average diameter of 180 nm, equated with the pore size of AAO template. In a certain extent, PVP can prevent the agglomeration and optimize the size of the nanowires. Besides, the PVDF-templated nanowires preferentially crystallize to the β-phase due to the nano-confinement effect, however, there is no chemical reaction during this process.关键词：PVDF nanowires;template-wetting;anodic porous alumina;nano-confinement;piezoelectric phase98|163|1更新时间：2020-08-12
- 摘要：Quantum dot light-emitting diodes (QDLED) with structure ITO/poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate) (PEDOT:PASS)/poly(N,N-bis(4-butylphenyl)-N,N-bis(phenyl)benzidine(poly-TPD)/QD/1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi)/LiF/Al were fabricated. By optimizing the concentration of quantum dots, maximum external quantum efficiency (EQE) of 0.83% and maximum emission luminance of 4 076 cd/m2 were achieved at a QD concentration of 30 mg/mL. In order to further improve the efficiency of QDLED, QDs were doped into polymer poly(N-vinylcarbazole) (PVK) and 1,3-Bis(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)benzene (OXD-7) so as to balance the injection of electrons and holes, reduce the aggregation of QDs and improve the surface of the films. Devices with structure ITO/PEDOT:PASS/poly-TPD/(PVK:OXD-7):QD/TPBi/LiF/Al were fabricated by spin coating and thermal evaporation. By optimizing the doping concentration of QDs, the maximum EQE of 1.97% is obtained, which is 2.3-fold higher than that of the undoped devices.关键词：quantum dot light emitting diodes;polymer PVK;doping127|174|4更新时间：2020-08-12
- 摘要：Using 1-octadecene as high-temperature reaction solvent, Eu-doped CdTe quantum dots were synthesized. The europium precursor was prepared by dissolving europium chloride into tributyl phosphate. Cadmium precursor solution was prepared by dissolving cadmium acetate into oleylamine, and Te precursor solution was prepared by dissolving tellurium powder into trioctylphosphine. CdTe and CdTe:Eu quantum dot were obtained at 200 ℃. The experiment results indicate that the fluorescence peaks of the quantum dots show obvious red shift with the increasing of europium content, but extra europium will lead to the decrease of fluorescence intensity.关键词：CdTe quantum dot;europium;doping;optical properties111|176|2更新时间：2020-08-12
- 摘要：Ru(bpy)32+-doped SiO2 nanoparticles were covered with the mixture of polyelectrolyte sodium polyacrylate and membrane-forming substance Nafion, and then the electrochemiluminescence (ECL) nanoparticles were acquired. The results show that ECL intensity of the polyacrylate-Nafion mixing membrane covered nanoparticles is enhanced 13 times, compared with the Nafion membrane covered nanoparticles. At the same time, there is an obvious increase of the exchangeable cation on the surface of the mixing membrane, and more Ru(bpy)32+ can be immobilized on the surface of the nanoparticles based on ion exchanging, and the corresponding ECL intensity can be enhanced about 3 times. Another significant advantage of the mixing membrane is that the as-prepared nanoparticles can label bio-macromolecule more easily based on the hydrophobic interaction. The results show that the labelled antibody still has good immune activity.关键词：signal enhancement;electrochemiluminescence nanoparticles;sodium polyacrylate;Nafion-mixing membrane;bio-labelling168|129|4更新时间：2020-08-12
- 摘要：In order to study the behavior of polyfluorene DSFX-SFX molecule in the air-water interface, the spectroscopic characteristics, and the effect of the orderly arrangement of molecular on the luminescence properties, Langmuir-Blodgett(LB) films of the polyfluorene DSFX-SFX were prepared. The π-A isothermal curve was studied, and the UV-Vis absorption and steady-state fluorescence spectra were measured. The experimental results show that the molecules lie flat on the subphase surface in the form of face-on. The single molecular area is 4.78 nm2. In chloroform solution, the absorption peak is at 354 nm, which belongs to π-π* electronic transition of the oxygen mixing into fluorene ring. The fluorescent emission peaks are at 396, 419, and 445 nm (shoulder), respectively. This is due to the emission of trimeric oxa anthracene, and the charge transfer between the fluorene ring and oxygen impurity anthracene ring. In LB film, the fluorescence spectra have an overall red-shifted of 6 nm. This is due to formation of an excimer, leading to the elevated HOMO and the reduction of LUMO. The orderly arrangement in ultra-thin film is propitious to blue fluorescence emission.关键词：LB film;spirofluorene oxygen complex;fluorescence spectra103|183|1更新时间：2020-08-12
- 摘要：In order to improve the performance of polymer solar cells, polyethylene glycol (PEG) was incorporated into PEDOT:PSS layer, and the effect of anode buffer layer modification on the performance of polymer solar cells was studied. First, the effect of PEG on the conductivity of PEDOT:PSS films was studied, and the results show that PEG interacts with PEDOT and PSS, and reorients the PEDOT polymer chains, which improves the conductivity of PEDOT:PSS layer significantly. PEDOT:PSS layer with 2%-4%(volume fraction) PEG has the optimized conductivity. Then the bulk heterojunction polymer solar cells based on PEG modified PEDOT:PSS anode buffer layer were prepared. It is found that PEG improves the short-circuit current density and fill factor obviously. The polymer solar cell with 2% PEG modified PEDOT:PSS layer gives the maximum power conversion efficiency, as compared with the control device without PEG, 24.4% efficiency enhancement is achieved.关键词：polymer solar cells;anode buffer layer;PEDOT:PSS;conductivity100|177|1更新时间：2020-08-12
- 摘要：Three different quantum barrier structures of GaN-based green LED were grown on Si(111) substrates, and then high power vertical structure LED chips were fabricated. The three kinds of quantum barrier structures were GaN, In0.05Ga0.95N/Al0.1Ga0.9N/In0.05Ga0.95N, In0.05Ga0.95N/GaN/In0.05Ga0.95N, and the corresponding three chip samples were A, B, C. The electroluminescence properties of these three kinds of chips with the same expitaxial structure except the quantum barrier structure were investigated at different forward current densities and ambient temperatures. Although the influence on luminous power is very small with the change of the quantum barrier structures, the change of the spectral properties is significant. Under 13 K, the EL peak wavelength blue shifts when the driving current increases from 0.01 to 400 mA, it is B>A≈C in sequence. While under 300 K, the difference in EL peak wavelength blue shift is A >B >C. At the same forward current densities, when the temperature increases from 13 to 320 K, the EL peak wavelengths of the three kinds of chips are S-shaped at most current, but are different shapes under extreme current. Perhaps, it is due to the fact that the differences in localized states, stress, piezoelectric filed and energy among these three kinds of quantum barrier structures lead to the different EL properties.关键词：quantum barrier structure;green LED;electroluminescence;Si substrate;MOCVD101|92|1更新时间：2020-08-12
- 摘要：In order to provide a reliable guidance for the spatial application of the 4T CMOS image sensor, temperature effects on 4T active pixel sensor CMOS image sensor from -40 ℃ to 80 ℃ were presented. The influences of temperature on conversion gain, full well charge, saturated output and dark current of the device were investigated. The experiment results show that the conversion gain of device decreases from 0.026 54 DN/e to 0.023 79 DN/e, the saturated output decreases from 4 030 DN to 3 396 DN, and the dark current increases from 22.9 e·pixel-1·s-1 to 649 e·pixel-1·s-1 with the temperature increasing. The decrease of conversion gain should be attributed to the decrease of the carrier mobility with the temperature increasing. The decrease of saturation output is mainly because of the decrease of the conversion gain which the influence of the conversion gain on saturated output is greater than that of the full well capacity with the change of temperature.关键词：CMOS image sensor;conversion gain;full well charge;dark current;temperature183|276|1更新时间：2020-08-12
- 摘要：The influences of size and spacing of n-type electrode on the current distribution of vertical-structure light-emitting diodes (VS-LEDs) were firstly analyzed by two-dimension circuit modeling, and annulospiral n-type electrodes were proposed for the fabrication of VS-LEDs. Then, finite element analysis model in Comsol Multiphysics was built to study the current density distribution in the active layer of VS-LEDs with the annulospiral electrodes. It is found that the current density distribution became more uniform when the electrode spacing reduced. Finally, VS-LEDs with various annulospiral electrodes were fabricated using high-reflectivity p-type Ohmic electrode, copper substrate electroplating and laser lift-off techniques. The wall plug efficiency of VS-LEDs with the electrode spacing of 146.25 μm is 26.8% at 350 mA, which is higher than that of VS-LEDs with other electrode spacings.关键词：GaN;vertical-structure light-emitting diodes(VS-LEDs);current distribution;annulospiral electrode175|146|4更新时间：2020-08-12
- 摘要：In order to optimize the conversion performance of all-optical wavelength converter and improve the quality of output signal, Q factor of wavelength converter was studied. Newton iteration method and four order Runge Kutta method were used to solve the transition rate equation and light propagation equations. The effects of the input signal power, optical pulse width, maximum mode gain, and length of the active layer on Q factor of the all-optical wavelength converter were also studied, and they were compared with the output extinction ratio under the same conditions. With the increasing of the input signal power, Q factor increases up to the maxima 8.819 dB which appears at -12 dBm of the input signal power, and then begin to decrease. Q factor decreases with the increasing of the optical pulse width, and increases with the increasing of the maximum mode gain and the length of the active layer. On the basis of the realization of the wavelength conversion, by optimizing the best parameter value, the value of Q factor reaching 16.680 dB is obtained, and the output signal quality is high. In order to obtain the high extinction ratio and Q factor at the same time to improve the quality of the output converted optical signal, the appropriate input signal must be selected for the optical power, pulse width, maximum mode gain, and length of the active layer.关键词：quantum-dot semiconductor optical amplifier;all-optical wavelength converter;cross phase modulation;Q factor98|113|0更新时间：2020-08-12
- 摘要：The reflectance and degree of polarization in the loss single negative bilayer were investigated by transfer matrix method. It is found that the angle dependent reflectance of p waves is larger than that of s wave, which is contrary to the usual material with both positive epsilon and mu. With the increasing of loss (electric loss and magnetic loss), the difference of Rp and Rs decreases, and the polarization degree is 0. The increasing of the thickness of MNG layer makes the dip in P shallow, while the increasing of the thickness of ENG layer makes the dip in P deep.关键词：reflectance;single-negative material;polarization75|181|0更新时间：2020-08-12
- 摘要：In order to understand the influence of some external factors on the fast light transmission system of stimulated Brillouin scattering, the transmission process was studied. Firstly, according to the 'Three wave coupling equation’, three kinds of photonic crystal fibers were selected. Then, a new type of photonic crystal fiber was selected. Through the comparison, a new type of photonic crystal fiber RB65 was selected. The results show that the fractional advancement of the fast light is the highest with the fiber length of 40 m, signal pulse width of 140 ns, and input signal power of 174 mW when the signal distortion is relatively small.关键词：photonic crystal fibers;stimulated Brillouin scattering;fast light97|186|2更新时间：2020-08-12
- 摘要：Red, blue, R:B=1:1, R:B=7:1 total 4 different light quality of LED plant lights were set as supplement light sources for potted aloe, and the influence of different light quality on the growth of aloe was researched using the indoor natural light as the blank control group. SPSS software was used for LSD multiple analysis of variance of the data. The results show that the red light source can promote aloe leaf elongation, the blue light source can promote the aloe leaf thickening, and the composite optical quality R:B=7:1 is the optimum light quality ratio with the best aloe growth effect.关键词：light-emitting diode;plant light supplement lamp;agricultural lighting;light quality ratio;least significant difference105|120|8更新时间：2020-08-12
- 摘要：A new method was presented to design the LED automotive light, such as the LED daytime running light (DRL) based on the thermal analysis. Firstly, a LED was modeling by COMSOL software. And an experiment was carried out to acquire the distribution of temperature on the surface of LED. The testing results show that the LED model is valid for the thermal analysis. Then based on the model, the relationships between LED junction temperature and the interval of LEDs, and thickness of MCPCB were discussed detailedly. Finally, considering the costs, the proposed design of the LED DRL is that the interval between LEDs is 37 mm and the thickness of MCPCB is 1 mm.关键词：LED automotive lights;daytime running lights;interval of LEDs;thickness of MCPCB;optimization design102|158|0更新时间：2020-08-12
- 摘要：Fluorescent molecular probes with high sensitivity, high selectivity, fast and convenient real-time in-field testing, are widely used to detect heavy metal ions. In this paper, we designed and synthesize a water-soluble fluorescent probe PN. PN could selectively detect mercury(Ⅱ) ions in aqueous solution. The small molecule probe PN afforded fluorescent intensity quench and decrease absorption of UV/Via spectrum in the presence of mercury(Ⅱ) ions. In order to achieve practical applications, PN is immobilized on the surface of SBA-15. The immobilization of fluorescent probe (SBA-PN) could selectively and sensitively detect mercury(Ⅱ) ions in a relatively wide pH range(4-10). Comparing with PN, the composite probe is more suitable for the recognition of mercury(Ⅱ) ions in water.关键词：fluorescent probe;immobilization;recognition;mercury(Ⅱ) ions155|90|1更新时间：2020-08-12
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