最新刊期
卷 33 ， 期 1 ， 2012
- 摘要：We demonstrate that power recycling is feasible by using a semi-transparent stripped Al electrode as interconnecting layer to merge a white organic light-emitting devices (WOLED) and an organic photovoltaic(OPV) cell. The device is called a PVOLED. It has a glass/ITO/CuPc/m-MTDATA∶V2O5/NPB/CBP∶FIrpic∶DCJTB/BPhen/LiF/Al/P3HT∶PCBM/V2O5/Al structure. The power recycling efficiency of 10.133% is achieved under the WOLED of PVOLED operated at 9 V and at a brightness of 2 110 cd/m2, when the conversion efficiency of OPV is 2.3%. We have found that the power recycling efficiency is decreased under high brightness and high applied voltage due to an increase input power of WOLED. High efficiency (18.3 cd/A) and high contrast ratio (9.3) were obtained at the device operated at 2 500 cd/m2 under an ambient illumination of 24 000 lx. Reasonable white light emission with Commission Internationale De L'Eclairage (CIE) color coordinates of (0.32,0.44) at 20 mA/cm2 and slight color shift occurred in spite of a high current density of 50 mA/cm2. The proposed PVOLED is highly promising for use in outdoors display applications.关键词：white organic light-emitting diode;contrast ratio;organic photovoltaic cell;PVOLED113|74|1更新时间：2020-08-12
- 摘要：CuInS2 nanocrystals were prepared by heating inorganic metal salt and dodecanethiol. It was found that absorption edge and photoluminescence peak shifted to shorter wavelength with decreasing the nanocrystal size due to quantum size effect. The overgrowth of as-prepared nanocrystals with a few monolayers of ZnS shell improved the photoluminescence quantum efficiency up to 48%. Further photoluminescence decays of CuInS2 nanocrystals were measured at room temperature. CuInS2/ZnS core/shell nanocrystals exhibited a longer photoluminescence lifetime, compared with the naked CuInS2 nanocrystals. This is because the surface coating of the ZnS shell passiviated the defects on the surface of CuInS2 nanocrystals and improved the photoluminescence quantum yield. Finally, CuInS2/ZnS core/shell quantum dot light emitting diodes were fabricated and their electroluminescence properties were studied.关键词：CuInS2;quantum dots;nanocrystals;light-emitting diodes118|120|0更新时间：2020-08-12
- 摘要：A series of Ca1-x-yWO4∶xPr3+,yLi+ deep red phosphors have been synthesized for white LEDs by high temperature solid state reaction. The crystal structure, surface morphology and spectral characteristics of the samples were investigated by the use of X-ray diffraction (XRD), SEM and fluorescence spectrophotometer. It is found that the synthesized crystalline powders are tetragonal system CaWO4. The particle size of pre-milling sample is more uniform and smaller than the manual grinded sample. The excitation-peaks are between 440 and 500 nm, and the main emission-peaks are located at 602, 620, 651 nm (Pr3+ion of 1D2→3H4, 3P0→3H6,3P0→3F2 transition). The peak at 651 nm has the strongest relative luminous intensity. The effects of doping density of Pr3+, Li+, calcining temperature and the addition of flux on the characteristics of luminescence have also been investigated. It shows that the Ca1-x-yWO4∶xPr3+,yLi+ can be used as red phosphors for blue light chips based white LEDs.关键词：Ca1-x-yWO4∶xPr3+;yLi+;white LEDs;red-shift;luminescence101|66|6更新时间：2020-08-12
- 摘要：The copolymer of polyfluorene/poly(p-Phenylene vinylenes) (PFO/PPV) was synthesized through Heck reaction. The structure of the obtained copolymer was characterized by FT-IR, 1H NMR, TGA, etc. The molecular weight and poly dispersity of the copolymer were 4 400 and 1.2, respectively. The copolymer had good thermal stability,it had only one weightlessness from RT to 700 ℃ and the weightlessness was about 50% at 350~450 ℃. EHOMO/ELUMO and Eg was-6.09/[KG-*4]-3.20 and 2.89 eV respectively. The optical properties, revealed by UV-Vis and PL, showed that copolymer had excellent luminescence, with a maximum peak of fluorescence emission at 490 nm. The copolymer was also tested as an emitting layer for flexible polymer light-emitting diode (PLED) device, where nano ZnO as a functional layer, showing a turn-on voltage of about 4.2 V and emitting blue electroluminescence.关键词：Heck reaction;luminescence materials;flexible device113|112|1更新时间：2020-08-12
- 摘要：The Y3Mg2AlSi2O12∶Ce3+ phosphor was synthesized by sol-gel method. Phase analysis of prepared samples was carried out by X-ray diffraction. The morphology was observed by scanning electron microscopy (SEM), and the excitation and emission spectra were determined. The results show that the crystal structure of synthesized Y3Mg2AlSi2O12 is consistent with Y3Al5O12(Yttrium aluminum garnet), and morphology displays the equiaxial granular characteristics. The emission band of the phosphor is wide, and the peak is near 580 nm, corresponding to the 4f65d1-4f7 typical transitions of Ce3+ and the excitation spectrum has two peaks at 340 nm and 468 nm, indicating that the phosphor can be excited effectively by blue light. The spectral intensity is significantly influenced by the doping concentration of Ce3+, and reaches a maximum value at the doping mole fraction of 6%. Moreover, composition replacement results in phase transformations of Y3Mg2AlSi2O12∶Ce3+ and influences luminous property.关键词：Y3Mg2AlSi2O12∶Ce3+;silicate;sol-gel method;phosphor190|61|0更新时间：2020-08-12
- 摘要：The effect of mercaptopropionic acid (MPA) molecules on the charge transfer process from the quantum dots to ZnO nanocrystal films was studied in this paper by the steady-state and time-resolved photoluminescence spectroscopy. The obtained high efficiently photoluminescent CdSe-core CdS/ZnS-multishell quantum dots with few defects are air stable in quantum dot based devices. Three samples were prepared to make the measurements of time-resolved photoluminescence spectra, CdSe quantum dots film, CdSe quantum dots spun cast on ZnO nanocrystal film (CdSe/ZnO), and MPA molecules linked CdSe quantum dots and ZnO nanocrystal film (CdSe/MPA/ZnO). The shortening of photoluminescence life times of CdSe quantum dots deposited on ZnO nanocrystal films with and without MPA molecules indicated the electron transfer process happened in the interface between CdSe quantum dots and ZnO nanocrystals. But the decreased rate of electron transfer from CdSe quantum dots to ZnO nanocrystal films with MPA molecules was found, compared to the electron transfer rate of the CdSe/ZnO sample. Considering the fact that MPA molecules did not improve the charge transfer process from CdSe quantum dots to ZnO nanocrystal films,it was indicated that the MPA molecules was not a good choice in CdSe quantum dot sensitized solar cell. The experimental result suggested that the direct adsorption of CdSe quantum dots on metal oxide nanocrystal films would obtain quantum dot sensitized solar cell with higher power conversion efficiency.关键词：mercaptopropionic acid;quantum dot;electron transfer;photoluminescence107|162|0更新时间：2020-08-12
- 摘要：Different contents of Ge and Al co-doped SiO2 films are prepared by RF magnetron sputtering technique and thermal annealing. From XPS spectra determination,we make sure the films contents and structure.Then we also determine the films PL spectra,which exhbit a V-band in around 420 nm beam and a B-band in 470 nm beam.Our experiments suggest that doped Al not improves luminescence efficiency of GeNOV and SiNOV defects centres but is of advantage to the defect centres fabrication.关键词：photoluminescence;Ge/Al-SiO2 film;defects centres;RF magnetron sputtering94|50|1更新时间：2020-08-12
- 摘要：Trivalent terbium (Tb3+) doped lithium aluminate(LiAl5O8) was synthesized by sol-gel method and the luminescent properties were investigated in this paper. The X-ray diffraction patterns (XRD) showed that the phosphors sintered at 750 ℃ for 2 h were pure LiAl5O8 phase.The excitation spectrum consisted of a broad band,in which the higher energy peaks located at 231 nm.The emission spectrum was composed of four narrow bands and the strongest emission peak was located at 542 nm, corresponding to the5D4→7F5 transition of Tb3+. The appropriate doping molar fraction of Tb3+ was 0.01 for the 542 nm emission.The effect of amount of Tb3+ doping content, the compensators (Li+) and flux (H3BO3) on the emission intensity of the phosphor were also studied. The results show that the emission intensity can be controlled by the above factors, and the intensity can be enhanced by selecting the prime optimum conditions.关键词：Tb3+;lithium aluminate;sol-gel method;green phosphor94|80|0更新时间：2020-08-12
- 摘要：Three iridium(Ⅲ) containing imidazo[1,2-a]pyridine complexes (PIPy)2Ir(acac), (4'-MPIPy)2Ir(acac), (BIPy)2Ir(acac) were synthesized based on reaction of iridium trichloride hydrate, 2-Biphenyl-4-yl-imidazo[1,2-a]pyridine with acetylacetone. Doping multiplayer OLEDs were respectively fabricated based on (BIPy)2Ir(acac) with electron transporting ability. The doping device showed strong saturated green electrophosphorescent emission, the emission peak wavelength 516 nm and brightness of 18 000 cd/m2, current efficiency of 26.7 cd/A with Commission International de L'Eclairage(CIE) coordinates of (0.32, 0.60). This is the first report on new green phosphorescent material based on Ir(Ⅲ) complex.127|114|0更新时间：2020-08-12
- 摘要：White organic light-emitting devices (WOLEDs) with double light-emitting layers (EMLs) were fabricated, which were based on phosphorescent blue bis[3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium Ⅲ](FIrpic) and yellow bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2'] iridium (acetylacetonate) [(t-bt)2Ir(acac)]. Device structure was given as:ITO/TAPC (30 nm)/host:(t-bt)2Ir(acac)[(10-x) nm, 4%]/spacer (x nm)/host:FIrpic (15 nm, 8%)/Bphen (40 nm)/Mg∶Ag (200 nm), while p-type 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and n-type tris[3-(3-pyridyl)-mesityl]borane (3TPYMB) was separately employed as the host, and device optimization was made by introducing a spacer between the two EMLs. The results showed that, compared with that of spacer-without device, the devices employed a spacer yielded higher device performance as well as stable white emission. For TAPC as the host, a device with spacer obtained maximum luminance of 19 550 cd/m2 and power efficiency of 8.3 cd/A, while 3TPYMB as the host, a device with spacer achieved maximum luminance of 1 950 cd/m2 and power efficiency of 30.7 cd/A. It was suggested that by incorporating a spacer in the WOLEDs, charge carrier recombination zone was broadened, and electron-hole balance was improved in the EMLs.关键词：white organic light-emitting devices;phosphorescent emitters;double EMLs;spacer100|159|4更新时间：2020-08-12
- 摘要：Microwave was applied to improve the efficiency of polymer solar cell based on poly(3-hexylthiophene) (P3HT) and [6, 6]-phenyl-C61-buytyric acid methyl ester (PCBM) bulk-heterojunction solar cells. With microwave radiation (2.45 GHz) for 10 min, short circuit current of 9.13 mA/cm2, open circuit voltage of 0.63 V, and energy conversion efficiency of 3.21% were obtained, similar or surpass to those of devices annealed with a hot plate for 20 min at 150 ℃. We examined the effect of microwave on the active layer. From the Uv-Vis absorption spectrum and the SEM image after microwave, we found that more rough morphology and larger phase separation occurred, which benefit for dissociation of exciton and transportation of carrier.关键词：polymer solar cells;microwave annealing;SEM98|156|2更新时间：2020-08-12
- 摘要：The GaN based metal-insulator-semiconductor (MIS) ultraviolet (UV) photodetectors were fabricated. The dark I-V curves and responsivity spectrum of the photodetectors were mea-sured, and the current transport mechanisms were analyzed. By analyzing the current transport mechanics, it was found that the tunneling-recombination mechanism dominated at the reverse bias and with the forward bias increasing, the current transport mechanism changed from tunneling mechanism to space charge limited current (SCLC) mechanism. Under 5 V reverse bias, it was found that the best responsivity and detectivity of the GaN based MIS detector were 170 mA/W and 2.3×1012 cm·Hz1/2·W-1 at 315 nm. The photo-voltages of GaN based UV photodetectors of different depth of insulator layers were studied, and it was found that the photo-voltage was limited by the tunneling procedure and leakage current.关键词：GaN;Si3N4;UV detector;current transport mechanics132|123|4更新时间：2020-08-12
- 摘要：Based on Night Vision and Electronic Sensors Directorate (NVESD) target acquisition performance (TAP) models, from the aspect of clutter impact on human-in-loop TAP and aimed at characteristics of laser jamming image out of the field of view, a modified TAP model is applied to analyze laser jamming image. Experimental results of laser jamming to CCD out of the field of view show that the method can reflect the influence of laser jamming image on search and detection probability. Hence, the validity of this method is verified.关键词：out of the field of view;laser jamming;NVESD;target acquisition performance;clutter;POE121|119|1更新时间：2020-08-12
- 摘要：Due to the basic characteristics of InGaAsSb/AlGaAsSb, based on the calculate lattice constant and energy band of quaternary system through the calculation of structure constants of binary system and ternary system, and analyze the MBE growth parameters and process, we design and grow the InGaAsSb/AlGaAsSb multi-quantum-wells epitaxial materials. The characterization of the layers has been carried out by X-ray double crystal diffraction and photo luminescence. There are several satellite peaks in X-ray double crystal diffraction results which indicate that these prepared InGaAsSb/AlGaAsSb multi-quantum-Wells are with high crystallized quality. The results of PL spectra at the room temperature indicate that the wave length are modulated from 1.6 to 2.28 μm, the narrowest PL FWHM is 22 meV.关键词：InGaAsSb/AlGaAsSb;multi-quantum-wells;X-ray double crystal diffraction;luminescence properties97|91|0更新时间：2020-08-12
- 摘要：A novel organic electroluminescent device was fabricated by interposing a thin LiF layer in Alq3 layer in this work. The structure of the device is ITO/NPB (45 nm)/Alq3 (x nm)/LiF (0.3 nm)/Alq3 /Al (150 nm). All the devices (x=5, 10, 15) showed expanded EL spectra, and the spectrum expanding is more obvious in the device with x=10 than the others. The highest brightness of this device reached 8 260 cd/m2 at a fixed bias of 22 V. The spectra contain tricolor, so this is a simple method to realize white light emitting. We also elucidated the mechanism for expanded EL spectra and investigated the properties of these devices.关键词：organic electroluminescent device;spectrum expanding;LiF;excitons120|135|0更新时间：2020-08-12
- 摘要：Carbon nitride nanotips were prepared on silicon substrate in plasma-enhanced hot filament chemical vapor deposition system, in which methane, hydrogen and nitrogen were used as the reaction gases. The carbon nitride nanotips were characterized by scanning electron microscopy and micro-Raman spectroscopy. The photoluminescence of the carbon nitride nanotips was measured at room temperature and the photoluminescence spectrum shows two emission bands at 406 and 506 nm. Combined with the Raman spectrum, the microstructure of the carbon nitride was analyzed. According to the structure and photoluminescence mechanism of amorphous carbon nitride films, the photoluminescence of carbon nitride nanotips was studied.关键词：carbon nitride nanotips;Raman spectrum;microstructure;photoluminescence mechanism96|121|0更新时间：2020-08-12
- 摘要：We studied the effects of trimethyl-aluminum (TMAl) preflow on the properties of AlN films grown on (0001) sapphire substrates via metalorganic chemical vapor deposition using high-temperature treatments. Short TMAl preflow treatments had little effect on the surface morphology of the AlN films, but hexagonal islands appeared on the surface when the TMAl preflow time increased. As the preflow time increased, the crystalline quality decreased and the stress state of the AlN films also changed. The origin of this stress behavior can be explained through a combination of extrinsic stress and intrinsic stress.关键词：metalorganic chemical vapor deposition;AlN;TMAl preflow;stress127|151|0更新时间：2020-08-12
- 摘要：OLEDs with configurations of ITO/CuTcPc/NPB/Alq3∶C545T/Alq3/LiF/Al,ITO/CuTcPc/NPB/Alq3∶C545T/Alq3/Al were fabricated using CuTcPc as electron injection layer, NPB as hole transport, layer Alq3∶C545T as emission layer, and Alq3 as hole transport layer. In our experiments, the CuTcPc treated devices have greater luminances than that of the conventional devices. As holes are the majority carriers in these multilayer OLEDs, the increased hole injection should lead an imbalance of carrier and a lower efficiency. But through our experiment, it is found that both the hole injection and the electron injection are increased after CuTcPc surface treatment. CuTcPc surface treatment can not only improve the luminances and the current density, but also can improve the current efficiency of the devices comparing with the conventional devices.关键词：CuTcPc;organic light emitting-diodes;carrier charge imbalance;current efficiency120|199|0更新时间：2020-08-12
- 摘要：InGaN/GaN-based blue and green light emitting diodes (LEDs) were under an aging with DC current of 900 mA at room temperature. The tunneling current was minimum after 24 h and 6 h for blue and green LED due to the thermal annealing effect which reduced defects. At the same time, the leakage current was minimum and light output was maximum. Then the leakage current increased and luminous flux reduced for green LED. The thermal annealing effect and defect generation were proposed as positive and negative accelerating factor, respectively. The negative accelerating factor of green LED increased quicker than that of blue LED and green LED decreased seriously. The results of analysis have a certain reference value for the improve of GaN LED.关键词：light-emitting diode;GaN;electrical stresses;I-V characteristics;luminous flux113|101|2更新时间：2020-08-12
- 摘要：We report white organic light-emitting devices (WOLEDs) based on blue fluorescent and yellow phosphor-sensitized-fluorescent emission. In the devices, 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-bipheny (BCzVBi) acts as a blue emitter, and 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) sensitized by a phosphorescent material, fac tris(2-phenylpyridine) iridium [Ir(ppy)3], acts as a mixed yellow light-emitting layer. By optimizing the doping concentration of dyes and introducing an interlayer, efficient WOLEDs with high color rendering index (CRI) values are obtained. In particular, one device shows a very high CRI value of 90 with a Commission Internationale De l'Eclairage coordinates of (0.32,0.32) at 100 cd/m2. The maximum current efficiency of the WOLEDs is 11.00 cd/A and the highest brightness of the device is 13 330 cd/m2.关键词：WOLED;CRI;blue fluorescent;phosphorescence sensitized128|127|4更新时间：2020-08-12
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Fluorescence Detecting of Carbazole-containing Poly(phenyleneethynylene)'s Thin Film to TNT Volatile
摘要：Poly(phenylene ethynylene) containing carbazole unit in the main-chain (PPECz) was synthesized by Pd-catalyzed Sonogashira coupling reaction between 3,6-dibromo-9-octylcarbazole and 2,5-dimethoxy-1,4-diethynylbenzene. PPECz in the solution and thin film exhibits obvious luminescence properties, which can be used to detect TNT sensitively. The fluorescence intensity of PPECz thin-film can be quenched 56% by the volatile of 40 μg TNT solid at 60 s at normal atmospheric temperature and pressure. This strategy can provide a platform for developing highly sensitive and efficient chemo sensors for warfare explosives.关键词：poly (phenylene ethynylene);carbazole;TNT volatile;fluorescence quenching92|158|1更新时间：2020-08-12 - 摘要：(Cu,Al)-doped ZnO thin films were deposited by an inductively coupled plasma enhanced physical vapor deposition system. The magnetic properties were measured by a superconducting quantum interference device magnetometer, and room-temperature ferromagnetism was observed in the (Cu,Al)-doped ZnO thin films. The surface characteristics of (Cu,Al)-doped ZnO thin films were studied by confocal Raman spectroscopy. Two different Raman spectra were performed: A confocal Raman measurement was used to characterize the defects at the surface and interface by focusing at different depths; A mapping mode was performed along a slope which was processed by a mask. The central position and the intensity of A1(LO) resonance peak were analyzed. The results indicate that the lattice stress and defects at the interface were obvious, while these lattice stress and defects at the interface will enhance the ferromagnetic properties of (Cu,Al)-doped ZnO thin films.关键词：ZnO;diluted magnetic semiconductor;interface;Raman spectrum119|81|0更新时间：2020-08-12
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