作者：
张艳芳李岚张晓松奚群Institute of Material Physics
Tianjin University of Technology Key Laboratory of Display Materials and Photoelectric Devices Ministry of Education The Tianjin Key Laboratory for Optoelectronic Materials and Devices
The well crystalline YAG：Ce^3＋ phosphor was synthesized by sold-state method, and the temperature dependence of excitation and emission spectra of YAG：Ce^3＋ phosphor were investigated in the temperature range from...
详细信息
The well crystalline YAG：Ce^3＋ phosphor was synthesized by sold-state method, and the temperature dependence of excitation and emission spectra of YAG：Ce^3＋ phosphor were investigated in the temperature range from room temperature to 573 K. With temperature increasing, it was noted that the emission intensity of as-repared phosphors decreased considerably more rapidly when pumped by 460 nm than by 340 nm. The temperature-intensity curves under different excitation wavelengths were obtained using an Arrhenius function, and the corresponding activation energies were also obtained respectively. Thus, the experimental phenomenon was discussed in terms of nonradiative decay rate. The effects of as-prepared phosphors on the performance of the white LED with changing temperature were also studied.
In this text, the films of CuTPP, ZnTPP were prepared at three different surface pressures of 15, 23 mN/m by LB technology. In order to search for the gas-sensing identities of CuTPP, ZnTPP LB films and initially esta...
详细信息
In this text, the films of CuTPP, ZnTPP were prepared at three different surface pressures of 15, 23 mN/m by LB technology. In order to search for the gas-sensing identities of CuTPP, ZnTPP LB films and initially establish the material system of sensitive gas sensors for detecting organic gases, the changes of UV-visible absorption spectrums of CuTPP, ZnTPP LB films respectively exposed in vapor of pyridine, ethyl acetate and THF were analyzed. The experimental results showed that the best metalloporphyrin LB films are prepared at the constant surface pressure of 23 mN/m. Moreover, it was found that different responses of UV-visible absorption spectrum of CuTPP LB film and ZnTPP LB film respectively for the three different gases. Therefore, CuTPP LB film matched with ZnTPP LB film could be used as chromatographic array units to identify vapor of pyridine, ethyl acetate and THF.
To obtain high efficiency microcrystalline silicon solar cell in single chamber, a series of intrinsic microcrystalline silicon thin films were prepared by very high frequency plasma enhanced chemical vapor deposition...
详细信息
To obtain high efficiency microcrystalline silicon solar cell in single chamber, a series of intrinsic microcrystalline silicon thin films were prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at different deposition conditions. The structural and electrical properties of these films were researched. Based on the experience of device grade intrinsic microcrystalline silicon used in multi-chamber, through the choice of suitable intrinsic layer and p seeding layer technique, the single junction microcrystalline silicon solar cell with 6.23% (1 cm2) conversion efficiency has been fabricated in single chamber.
The two-mode squeezed even and odd coherent states are quantum states with some non-classical *** entanglement of two-mode squeezed even and odd coherent states are measured by non-classicality of P-functionand separa...
详细信息
The two-mode squeezed even and odd coherent states are quantum states with some non-classical *** entanglement of two-mode squeezed even and odd coherent states are measured by non-classicality of P-functionand separability inequalities of EPR-operators.
We present the influences of Gd3+co-doping and temperature on the photoluminescent spectra of (Y2.94-xGdxCe0.06) Al5O12phosphors. The luminescence wavelength is shifted from 530 nm to 550 nm by addition of the Gd3+inc...
详细信息
We present the influences of Gd3+co-doping and temperature on the photoluminescent spectra of (Y2.94-xGdxCe0.06) Al5O12phosphors. The luminescence wavelength is shifted from 530 nm to 550 nm by addition of the Gd3+increasing from 0 to 0.6 mol, at room temperature. The peak intensity shows the normal redshift with broadening bandwidth and decreasing emission intensity as increasing in temperature. With the increasing of Gd3+doping, the declining rate and dilated trend are aggravated. The redshift behavior can be described in terms of the level splitting between ground state and excited state because of the relative larger radius and more negative of the Gd3+than that of the Y3+based on the configuration coordination model. The formula explanation is due to the dominant electron-phonon interaction for thermal decay and bandwidth broadening.
White organic light-emitting diodes were fabricated by using a novel phosphorescence bis（1,2-diphenyl-1H-benzoimidazole）iridium（acetylacetonate）[（pbi）2Ir（acac）] as sensitizer and a fluorescent dye of 4- （dicy...
详细信息
White organic light-emitting diodes were fabricated by using a novel phosphorescence bis（1,2-diphenyl-1H-benzoimidazole）iridium（acetylacetonate）[（pbi）2Ir（acac）] as sensitizer and a fluorescent dye of 4- （dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） codoped into a carbazole polymer of poly（N-vinylcarbazole） （PVK）. Through characterizing the UV-Vis absorption spectra, the photoluminescence spectra of （pbi）2Ir（acac） and DCJTB, and the electroluminescence spectral properties of the WOLEDs, the energy transfer mechanisms of the codoped polymer system were deduced. The results demonstrate that the luminescent spectra with different intensity of （pbi）2Ir（acac） and DCJTB were co-existent in the EL spectra of the blended system, which is ascribed to an incomplete energy transfer process in the EL process. The efficient Forster and Dexter energy transfer between the host and the guests enabled a strong yellow emission from （pbi）2Ir（acac） and DCJTB, where （pbi）2Ir（acac） plays an important role as a phosphorescent sensitizer for DCJTB. With the blue emitting-layer of N,N＇-diphenyl-N,N＇-bis（1- naphthyl）（1,1＇-biphenyl）-4,4＇-diamine, the codoped system device achieved white emission. The codoped system showed that its Commissions Internationale de 1＇Eclairage coordinates were more independent of the variation of bias voltage than those of phosphorescent doped PVK systems.
Polymer light-emitting diodes (PLEDs) attract more and more attention because of their potential application in flat panel displays. PLEDs based on phosphorescent europium complexes show good color purity. For europiu...
详细信息
Polymer light-emitting diodes (PLEDs) attract more and more attention because of their potential application in flat panel displays. PLEDs based on phosphorescent europium complexes show good color purity. For europium complexes based PLEDs, the usual practice is to utilize the blend of poly(N-vinylcarbazole) (PVK) in the presence of electron-transporting compound 2-(4-biphenylyl)-5-(ptertbutylpheny1)-1, 3, 4-oxadiazole (PBD) whose mass fraction is 30%, as the host. Efficient red PLEDs based on functionalized europium complexes Eu(TPD)3Phen and Eu(Ph-TPD)3Phen synthesized via Suzuki coupling reaction are fabricated with poly(9, 9-dioctylfluorene) (PFO) in the presence of 30% (mass fraction) PBD as the host. The performances are comparable to that of the PLEDs with PVK:PBD as the host. For the two europium complexes, the maximum luminance efficiencies of the PLEDs of 0.12 cd/A and 0.45 cd/A are achieved with emission peak at 619 nm.
The UV-Vis absorption and photoluminescence (PL) spectra of a novel fluorene molecular derivative of 2, 3-bis(9, 9-dihexyl-9H-fluoren-2-yl)-6, 7-difluoroquinoxaline (F2Py) are investigated. The PL peaks of F2Py in sol...
详细信息
The UV-Vis absorption and photoluminescence (PL) spectra of a novel fluorene molecular derivative of 2, 3-bis(9, 9-dihexyl-9H-fluoren-2-yl)-6, 7-difluoroquinoxaline (F2Py) are investigated. The PL peaks of F2Py in solution and film state are at 452 and 448 nm respectively, and the peak of the blend of F2Py and NPB film is at 544 nm, which is significantly red shifted compared with the PL spectra of individual component. For the further research of electroluminescent properties, OLEDs based on F2Py are fabricated by vacuum deposition. In the electroluminescence (EL) spectra of devices, a green emission band around 530~550 nm is observed, which is considered as the light emission from exciplex formed at the interface of NPB and F2Py. A shoulder peak about 430 nm formed by both F2Py and NPB excitons has been also observed. A turn-on voltage of 17 V and a maximum luminance of 58 cd/m2are obtained when the device has a 50 nm F2Py layer. However, a triple layer device with a thin layer of Alq3as an electron transporter and 20 nm thickness of F2Py has shown a maximum luminance of 5030 cd/m2and a low turn-on voltage of 8 V.
Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties...
详细信息
Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties were characterized by X-ray diffraction （XRD） technique, four-point probe method and spectrophotometer. The results show that the deposited ITO film with introduced H2O during sputtering process was almost amorphous. The average visible light transmission of 100 nm ITO film was around 85% and square resistivity was below 80 Ω/square. The film was used as the transparent anode to fabricate an inverted top-emitting organic light-emitting diodes （IT-OLEDs） with the structure of glass substrate/Alq3 （40 nm）/NPB （15 nm）/CuPc （x nm）/ITO anode （100 nm）, where the film thickness of CuPc was optimized. It was found that the luminance of this IT-OLEDs was improved from 25 cd/m^2 to more than 527 cd/m^2 by increasing the thickness of CuPc, and luminance efficiency of 0.24 lm/W at 100 cd/m^2 was obtained, which indicated that the optimized thickness of CuPc layer was around 15 nm.
暂无评论