Flexible organic light-emitting diodes with ITO／Ag／ITO multi-layers as anodes

The transparent ITO/Ag/ITO multi-layers are developed as anodes on flexible PET (poly(ethylene terephthalate)) substrates. The influence of these anodes on FOLED (Flexible Organic Light-emitting Diodes) is investigated. From the results of research, it can be seen that the multi-layer anode has optimum characteristics, whose sheetresistance is 11 Ω and optical transmittance is about 80%,when the thickness of Ag sandwiched by two ITO layers is in the range of 14--18 nm. It is demonstrated that the OLED devices with multi-layer anodes give better luminescence and higher efficiency compared with those with single ITO anodes.     

有机电致发光白光器件的研究

白光有机电致发光器件在显示领域有着极大的应用前景,受到人们广泛的关注.通过对白光有机电致发光器件的结构、工作原理、实验的可行性分析、工艺流程、存在的问题等方面进行了分析,对器件结构进行了优化设计,确定了合理的技术路线,提高白光电致发光器件中各成分的发光效率,从而得到了一种较为理想的有机白光电致发光器件.     

LiF用作阴极注入层的有机发光二极管制备

使用真空热蒸发方法,制备了结构为ITO/TPD/Alq3/LiF/Al的有机发光二极管,其中LiF用作阴极注入层,LiF超薄层的加入,增强了电子注入,降低了启亮电压,提高了器件的发光效率和亮度. 实验结果表明:当加入LiF层的厚度为0.5 nm时,器件性能的改善最好,和不含LiF的器件相比,启亮电压由原来的9 V降低到5 V,效率由1.5 cd/A增加到3.3 cd/A,提高了近1倍,然而随着加入LiF层厚度的增加,器件性能的改善效果降低.     

有机发光二极管中不同金属电极引起的奇特磁效应

采用三类金属阴极材料Ca,Al和Cu（Au）通过分子束沉积和电子束加热方式制备了有机发光二极管ITO/CuPc/NPB/Alq3/金属阴极,并在300,200,150,100,50和15K6个温度下,分别测量了不同电极器件的发光随外加磁场的变化（即Magneto-ElectroLuminescence,MEL）.在室温300K下,发现Ca,Al和Cu（Au）电极器件的MEL在低场（0B50mT）均表现为快速上升;但随磁场（B〉50mT）的进一步增大,Ca和Al电极器件的MEL缓慢变大并逐渐趋于饱和,且与阴极的制膜方式无关;而采用电子束加热方式制备的Cu（Au）电极器件,其MEL却表现出高场缓慢下降;且温度越低,该类Cu电极器件MEL的高场下降更为显著.实验研究表明,Ca和Al电极器件的MEL主要是由超精细耦合作用随外加磁场变化引起的.但电子束加热方式制备的Cu（Au）电极器件的MEL除了超精细耦合作用引起的低场快速上升外,其高场下降的可能机制则是：Cu（Au）电极器件中电子-空穴对的俘获区（e-hCapture Zone）靠近阴极界面,相比较于热蒸发的方式,电子束蒸发的方式更容易使重金属Cu（Au）原子得到更高的能量,使其渗透进相邻的有机层Alq3中,Cu（Au）原子的强自旋轨道耦合作用导致电子-空穴对发生自旋翻转,此为MEL出现高场下降的原因.     

Dependence of the stability of organic light-emitting diodes on driving mode

We investigated the effects of pulsed current (PC) and direct current (DC) driving modes on the stability of organic light-emitting diodes with and without hole-injection layers (HILs).Two different HIL materials were used:copper phthalocyanine (CuPc) and 4,4’,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MDTATA).It was found that the half-lives of devices using PC driving modes were different from those of comparable devices using DC driving modes.For the devices without HILs,with CuPc HILs and with MTDATA HILs,the half-lives of the devices were changed by factors of 1.91,1.41 and 0.86,respectively,when operated in PC rather than DC driving modes.Our analysis of the electrical characteristics of the corresponding hole-only devices showed that the number of holes injected into devices was greatly reduced by inserting an m-MTDATA layer compared with other designs.The results indicate that different ratios of injected electrons and holes can be obtained in these devices.Moreover,these ratios play a dominant role in the dependence of the stability of the device on the driving mode.     

New hybrid encapsulation for flexible organic light-emitting devices on plastic substrates

The hybrid encapsulation for flexible organic light-emitting devices on plastic substrate was investi-gated. The hybrid encapsulation consisted of four periods of AIq3/L.iF layers as the pre-encapsulation layer and a flexible aluminum foil coated with getter as the encapsulation cap. We measured the device lifetime at a continuous constant current of 20 mA/cm2, which corresponded to an initial luminance of 2000 cd/m2. The half-luminance decay time of the encapsulated device was about 458 h. More over, the hybrid encapsulation is ultrathin and flexible, ensuring device bendability.     

High efficient light-emitting diodes using polystyrene as matrix

High efficient polymer light-emitting diodes (PLEDs) were obtained by using a blend of conjugated polymer G-PF, a copolymer of fluorene and thiophene, and polystyrene (PS). The maximum electroluminescent (EL) efficiency of the device is 12 cd/A when G-PF/PS weight ratio is at 80/20, while that of pure G-PF device is 6.5 cd/A. Studies on photoluminescence and electroluminescence of the blends indicate that inter-chain interactions were tremendously suppressed due to the dilution effect. However, after PS concentration exceeds 20% the EL efficiency of the devices decreases with further increase of PS concentration. This may be due to the decrease of the recombination probability of electrons and holes with the excessive addition of PS insulator.     

Efficient polymer light-emitting diodes with violet blue emission based on blends of PSiF6-PPP and PSiFC6C6

Efficient polymer light-emitting diodes (PLEDs) with violet blue emission were fabricated using blends of copolymers of paraphenylene-co-silafluorene (PSiF6-PPP) and polymer of poly (9,9'-alkyl-3,6-silafluorene) (PSiFC6C6). The performances of the devices are sensitive to the blend ratio. When the mass ratio of PSiF6-PPP to PSiFC6C6 is 1 : 3, the highest external quantum efficiency is 1.96% at luminance of 105 cd.m2, its electroluminescent (EL) spectrum peaks at 398 nm and full width at half maximum is 67 nm. The improvements of the device performances were due to the energy transfer from PSiFC6C6 to PSiF6-PPP and the balanced injection of electrons and holes.     

Transparent organic light-emitting diodes based on Cs<Subscript>2</Subscript>CO<Subscript>3</Subscript>:Ag/Ag composite cathode

The transparent organic light-emitting diodes (TOLEDs) based on Cs 2 CO 3:Ag/Ag composite cathode are reported in this paper.They show higher efficiency and better stability than the control devices with the Cs 2 CO 3 /Ag cathode.The devices are highly transparent,and show total efficiencies from both sides of the devices comparable with conventional bottom-emitting devices.The electroluminescence (EL) spectrum from the cathode side of the device is closer to the photoluminescence (PL) spectrum of the light...     

Tunable and enhanced luminescence of Ba2−xCaxSiO4−yN2/3y:Eu2+ phosphors for white light-emitting diodes

Color tuning and luminescence enhancement are predominant challenges for improving the performance of white light emitting diodes(LEDs) toward commercial application. In this paper, a novel promising Ba_(2-x)Ca_xSiO_(4-y)N_(2/3y):Eu~(2+) tphosphors with tunable and enhanced luminescence for phosphors converted LEDs(pc-LEDs) have been successfully synthesized by a direct gas-reduction nitridation method. The effects of Ca and N doping on the phase purity, morphology and optical properties of Ba_(2-x)Ca_xSiO_(4-y)N_(2/3y):Eu~(2+) tphosphors were also systematically investigated. The optical results show that Ba_(2-x)Ca_xSiO_(4-y)N_(2/3y):Eu~(2+) tphosphors can be actively excited over a broad range from 250 to430 nm. With the adding of different concentrations of Ca~(2+) tions in phosphors, the emission color wavelength can be tailored from 501 to 441 nm by a 375 nm NUV LED excitation source. Furthermore, it has been found that the emission and absorption of Ba_(2-x)Ca_xSiO_(4-y)N_(2/3y) tphosphor can be significantly improved when N~(3-) ions were introduced into the host lattices. The intensity of Ba_(1.5)Ca_(0.5)SiO_(4-y)N_(2/3y):Eu~(2+) tphosphor was 3.4 times higher than the phosphor without N doping. The fabrication and characterization of pc-LEDs using Ba_(2-x)Ca_xSiO_(4-y)N_(2/3y):Eu~(2+) tphosphors-silica gel as the coating layer onto 375 nm-emitting In Ga N LED caps demonstrated the superior optical and current tolerant properties,making it a promising and competitive candidate for commercial utilization in white LED applications.     

Embedding Co3O4 nanoparticles into graphene nanoscrolls as anode for lithium ion batteries with superior capacity and outstanding cycling stability

Co_3O_4 is a promising high-performance anode for lithium ion batteries(LIBs), but suffers from unsatisfied cyclability originating duo to low electrical conductivity and large volume expansion during charge and discharge process. Herein, we successfully constructed the Co_3O_4 nanoparticles embedded into graphene nanoscrolls(GNSs) as advanced anode for high-performance LIBs with large capacity and exceptional cyclability. The onedimensional(1 D) Co_3O_4/GNSs were synthesized via liquid nitrogen cold quenching of large-size graphene oxide nanosheets and sodium citrate(SC) modified Co_3O_4 nanoparticles, followed by freeze drying and annealing at400 °C for 2 h in nitrogen atmosphere. Benefiting from the interconnected porous network constructed by 1 D Co_3O_4/GNSs for fast electron transfer and rapid ion diffusion, and wrinkled graphene shell for significantly alleviating the huge volume expansion of Co_3O_4 during lithiation and delithiation. The resultant Co_3O_4/GNSs exhibited ultrahigh reversible capacity of 1200 mAh g~(-1) at 0.1 C, outperforming most reported Co_3O_4 anodes.Moreover, they showed high rate capability of 600 m Ah g-1 at 5 C, and outstanding cycling stability with a high capacity retention of 90% after 500 cycles. Therefore, this developed strategy could be extended as an universal and scalable approach for intergrating various metal oxide materials into GNSs for energy storage and conversion applications.     

Three-dimensionally macroporous graphene-supported Fe3O4 composite as anode material for Li-ion batteries with long cycling life and ultrahigh rate capability

Fe3O4 is an attractive conversion reaction- based anode material with high theoretical capacity （928 mA h g^-1）. However, the poor cycling and rate per- formance hinder its applications in Li-ion batteries. In this work, we report an effective strategy to synthesize three- dimensionally macroporous graphene-supported Fe3O4 hybrid composite. Benefiting from advantage of the special structure, the hybrid composite exhibits excellent Li^＋ stor- age performance, delivering a high reversible capacity of 980 mA h g^-1at the current density of 4 A g^-1 even after 470 cycles and ultrahigh rate capability （293 mA h g^- 1 even at current density of 20 A g^-1）.     

白豹油田长3、长4+5低渗透储层定量分类评价研究

以白豹油田三叠系长3、长4 5为例,研究了低渗透储层定量分类问题.在对关键井研究与合理选择分类参数的基础上,采用Q型聚类分析和贝叶斯判别相结合,进行储层定量分类评价研究,建立判别函数,依据此判别函数对非取心井的目的层进行了定量分类评价.研究了储层在纵向和平面的分布规律,确定了有利储集区.结果表明,该定量分类评价可行,且具有较高的综合性和科学性.     

Assembly of gold nanoparticles with H10TTPR （3a, 4, 5, 8, 9, 9a, 10, 11-octa-hydro-2H,3H-1,6,7,12-tetrathia-perylene） as the rigid cross-linker

Gold nanoparticles were assembled with the rigid cross-linker, H10TTPR. The assembly process was studied with the UV-vis spectroscopy and TEM. By adjusting the amount of H10TTPR added to the gold nanoparticle solution,the aggregate form of gold nanoparticles could be controlled.