新型钙镁铝合金阴极对红光OLED性能的影响研究

采用不同比例的Ca/Mg/Al合金和纯Ca/Al合金阴极分别制备结构为ITO/Mo O_3(30nm)/NPB(40nm)/TCTA(10nm)/CBP:R-4B(30nm)/TPBI(10nm)/Alq3(30nm)/Ca:Mg(X%):Al(100nm)和ITO/Mo O3(30nm)/NPB(40nm)/TCTA(10nm)/CBP:R-4B(30nm)/TPBI(10nm)/Alq3(30nm)/Ca:Al(100nm)的红光有机电致发光二极管(OLED)器件及其对应的电子型器件,研究了阴极材料对器件的影响。结果发现,Ca/Mg/Al合金阴极可以提高阴极发射电子能力。当Mg掺杂质量比为20%时,器件具有最优性能,在电压为13 V时,发光亮度为10250 cd/m2,电流密度为57.099 m A/cm2,最大电流效率为18.8426 cd/A,效率较高且滚降比较平缓。原因为载流子注入比较平衡,形成了较多的激子。     

基于红光染料掺杂的有机电压调制发光器件

制备了一种电压调制有机发光二极管(OLED),结构为ITO/CuPc(10nm)/NPB(70nm)/MADN(30nm)/MADN:DCM(2%(质量分数),10nm)/BCP 7nm/ALQ(30nm)/LiF(0.5nm)/Al(100nm).通过调节DCM的掺杂浓度和MADN:DCM厚度,发光颜色发生了随电压的连续变化.该器件的起亮电压在3V左右,当驱动电压为16V时最大亮度达到16652cd/m2,电流效率在8V时达到最大为5.78cd/A.     

空穴注入层MoO_3厚度对蓝绿色磷光OLED发光特性的影响

以mCP为磷光主体材料,BGIr1为蓝绿色磷光掺杂材料,MoO3为空穴注入材料,制备5种不同厚度的MoO3蓝绿色磷光有机电致发光器件(OLED),并研究不同厚度MoO3空穴注入层对蓝绿色磷光OLED发光特性的影响。所制器件结构为ITO/MoO3(x nm)/NPB(40nm)/mCP∶BGIr1(30nm,18%)/BCP(10nm)/Alq3(20nm)/LiF(1nm)/Al(100nm),其中18%为发光层中BGIr1的掺杂量(质量分数),x为空穴注入层MoO3的厚度。研究结果表明,本实验制备器件空穴注入层MoO3的最佳厚度为20nm。当电压为13V时,MoO3厚度为20nm器件获得最大亮度为8 617cd/cm2,当电流密度为20mA/cm2时,器件获得最大发光效率为5.7cd/A。器件在488和512nm处获得两个主发射峰,发光颜色稳定,CIE坐标为(0.19,0.21)。     

原子力显微镜与X射线光电子能谱对ITO表面改性的研究

采用氧气等离子体(OP)处理对氧化铟锡(ITO)薄膜进行表面改性,通过原子力显微镜(AFM)、X射线光电子能谱(XPS)和四探针等测试手段对薄膜样品进行表征,研究了OP处理对ITO表面性质的影响.实验结果表明OP处理有效去除了ITO表面的污染物,优化了ITO表面的化学组分,降低了ITO表面的粗糙度和方块电阻,改善了ITO的表面形态.与此同时,通过XPS监测研究了OP处理后ITO表面化学组分随老化时间的变化,结果显示经过优化的化学组分随老化时间增加而逐渐退化.另外,以OP处理后经过不同老化时间的ITO样品作为空穴注入电极,制备了有机电致发光器件(OELD),通过测试器件的电压-电流-亮度特性,进一步研究了ITO表面性质对于OELD光电性能的影响.     

一种新型磷光铜(I)配合物及其高效绿光有机电致发光器件

研制出了一种新型的Cu(Ⅰ)配合物[Cu(DPEphos)(PyPPN)]BF4 (CuL1L2),其中二DPEphos和PyPPN分别表示(2-二苯基膦基)苯基醚和吡啶并[1′,2′∶2,3] 吡嗪[5,6-f] 1,10-菲罗啉,并制备了结构为ITO(20)/2-TNATA (20nm)/NPB(40nm)/CBP∶8% CuL1L2(30nm)/BCP(20nm)/Alq3(20nm)/ LiF(1nm)/ Al(100nm)的掺杂式有机发光二极管(OLED).掺杂式器件在530nm处有较强的金属配合物三重态的绿光电致磷光 (ELECTROPHOSPHORESCENCE,EPL)发射,最大亮度为2388cd/m2,在电流为0.1mA时,器件的最大电流效率达到11.4cd/A,据我们所知,该OLED器件的EL性能是目前报道Cu(Ⅰ)磷光配合物的EPL器件中最高的.     

OLED用ITO导电玻璃的研究进展

氧化铟锡(ITO)膜的电阻率及表面粗糙度将影响有机电致发光器件(OLED)的发光效率及其使用寿命.通过选择适当的工艺条件以及表面处理可以改善ITO膜的表面粗糙度、可见光透过率、电导率和功函数,以提高OLED的稳定性、发光效率和使用寿命.对薄膜的光学和电学性能进行了分析,提出了改进工艺的方向.     

主客体掺杂和空穴阻挡对蓝色磷光OLED发光性能的影响研究

以铱配合物蓝色磷光材料Firpic作为掺杂剂,制备了基于CBP为主体的蓝色有机电致发光器件,其结构为ITO/CuPc/FIrpic:CBP(x%)/BCP/Alq3/LiF/Al,其中x%为发光层主客体掺杂浓度.分别研究了主客体掺杂浓度和空穴阻挡层BCP的厚度对器件发光性能的影响,当掺杂浓度为8%时,主客体间的能量传转移最充分,器件的启亮电压为5V,器件在20V时的亮度为7122.25cd/m2.器件电致发光(EL)光谱出现明显的红移现象,为Alq3部分参与了发光,影响了发光的色纯度,改变BCP的厚度,可以调节载流子复合区域和器件发光的色度坐标,达到改善器件发光性能的目的.     

射频等离子体改性工艺与氧化铟锡薄膜性能研究

采用正交实验方法研究了氧气等离子体表面改性中各工艺因素对ITO薄膜表面性质的影响,获得了IID表面改性的最佳工艺条件,并且通过XPS,AFM,透射光谱的分析以及薄膜表面接触角和方块电阻的测量,表征了优化工艺条件下氧气等离子体处理前后ITO薄膜的表面性质.结果表明,氧气等离子体处理降低了ITO表面的粗糙度和方块电阻,改善了ITO表面的化学组分和浸润性能.另外,以表面处理前后的ITO基片作为空穴注入电极,采用真空热蒸镀技术制备了有机薄膜电致发光(OTFEL)器件,并对器件的电流.电压.亮度特性以及电流效率进行了测试和分析,实验结果显示,氧气等离子体处理降低了启亮电压和驱动电压,提高了发光亮度和电流效率,有效地改善了OTFEL器件的光电性能.     

Al2O3/DLC复合膜摩擦磨损性能的研究

为了提高铝合金零部件的摩擦磨损性能,采用微弧氧化和磁过滤阴极真空弧技术,在其表面制备了Al2O3/DLC复合膜.用X射线衍射分析(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、原子力显微镜(AFM)以及摩擦试验对复合膜的化学成分、结构、表面形貌及其对铝合金摩擦磨损性能的影响进行了研究.结果表明,在铝合金表面形成了120 μm厚的多孔Al2O3陶瓷膜,与基体结合紧密.外层0.1.μm厚的DLC不改变膜的表面形貌,但是降低摩擦因素,并且进一步提高膜的耐磨性.Al2O3/DLC复合膜为铝合金作为耐磨工件使用提供了很好的承载支持,并且使铝合金表面摩擦磨损性能大大提高.     

Al2O3缓冲层对以ZnO∶Al为阳极的有机电致发光器件性能的影响

采用直流磁控溅射法制备ZnO∶Al(AZO)透明导电薄膜,薄膜电阻率为5.3×10-4Ω.cm,可见光区平均透过率大于85%。采用施加缓冲层的方法,在AZO和NPB之间加入一层Al2O3绝缘薄膜,提高了AZO阳极有机电致发光器件的性能,分析了Al2O3缓冲层的作用机理。结果表明施加1.5 nm缓冲层后器件的电流效率是单纯AZO阳极器件的3.4倍,同时也高于传统ITO器件。     

Low Temperature DC Sputtering Deposition on Indium-Tin Oxide Film and Its Application to Inverted Top-emitting Organic Light-emitting Diodes

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.     

Organic light-emitting diodes having carbon nanotube anodes

Single-walled carbon nanotube (SWNT) films on flexible PET (polyethyleneterephthalate) substrates are used as transparent, flexible anodes for organic light-emitting diodes (OLEDs). For polymer-based OLEDs having the structure: SWNT/PEDOT-PSS:MeOH/TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)) + TPD-Si(2) (4,4'-bis[(p-trichlorosilylpropylphenyl)phenylamino]biphenyl) /BT (poly(9,9-dioctylfluorene-co-benzothiadiazole))/CsF/Al, a maximum light output of 3500 cd/m(2) and a current efficiency of 1.6 cd/A have been achieved. The device operational lifetime is comparable to that of devices with Sn-doped In(2)O(3) (ITO)/PET anodes. The advantages of this novel type of anode over conventional ITO are discussed.     

Trimethylsilane-containing donor-acceptor-donor type material for red fluorescent organic light-emitting diodes

In this paper, we described a donor-acceptor-donor type red fluorescence material, which have the bulky trimethylsilane groups in the donor moieties. To explore the electroluminescence properties of these materials, multilayered OLEDs were fabricated with a device structure of ITO/2-TNATA (60 nm)/NPB (40 nm)/Red 1 (2%):rubrene (50%):Alq3 (30 nm)/Alq3 (60 nm)/Liq (3 nm)/Al (100 nm). A device using Red 1 as the dopant material showed a maximum luminance of 5138 cd/m2 at 12.0 V, maximum luminous efficiencies of 1.62 cd/A, and maximum power efficiencies of 1.04 lm/W. The Commission Internationale de L'Eclairage coordinates of this device was (0.67, 0.33) at 7.0 V, which indicated stable color chromaticity at various voltages.     

Fabrication and characterization of organic light-emitting diodes using zinc complexes as hole-blocking layer

2-(2-Hydroxyphenyl)benzoxazole (HPB) was employed as organic ligand and the corresponding zinc complexes (Zn(HPB)2 and Zn(HPB)q) were synthesized. And their EL properties were characterized. The structures of zinc complexes were determined with FT-NMR, FT-IR, UV-Vis, and XPS. The thermal stability showed up to about 300 degrees C under nitrogen flow, which was measured by TGA. The photoluminescence (PL) of zinc complexes were measured from the DMF solution. The PL emitted in blue and yellow region, respectively. The EL devices were fabricated by the vacuum deposition. Two kinds of OLEDs devices were fabricated; ITO/NPB (40 nm)/Zn complexes (60 nm)/LiF/Al and ITO/NPB (40 nm)/Alq3 (60 nm)/Zn complexes (5 nm)/LiF/Al. Both of the EL properties as the emitting and the hole-blocking layer were investigated. The EL emission of Zn(HPB)q exhibited green light centered at 532 nm. The device showed a turn-on voltage at 5 V and a luminance of 6073 cd/m2 at 10 V. Meanwhile, the maximum EL the emission of the Zn(HPB)2 device was found to be at 447 nm. And the device showed a luminance of 2813 cd/m2 at 10 V. The ITO/NPB (40 nm)/Alq3 (60 nm)/Zn(HPB)2 (5 nm)/LiF/Al device showed increased luminance of L=17000 cd/m2 compared to L=12000 cd/m2 for similar device fabricated without the hole-blocking layer. And the turn-on voltage was significantly affected by the existence of the hole-blocking layer.     

Fabrication and characterization of white polymer light emitting diodes using PFO:MDMO-PPV

White polymer light emitting diodes (WPLEDs) with a glass/ITO/PEDOT:PSS/PFO:MDMO-PPV/ TPBI/LIF/Al structure were fabricated in order to investigate the optimum doping concentration of the emission materials. PEDOT:PSS was introduced as the hole transport material. The PFO and MDMO-PPV were used as the light emitting host and the guest materials, respectively. The PFO:MDMO-PPV mixed solution was spin-coated onto the PEDOT:PSS/ITO substrate. TPBI, LiF and Al were deposited by thermal evaporation as the hole blocking, electron injection, and cathode materials, respectively. As a result, the current density and luminance of the WPLED with the 20.0 wt% MDMO-PPV concentration in the PFO host material were found to be about 365 mA/cm2 and 4315 cd/m2, respectively. The maximum external quantum efficiency (EQE) of the same sample was found to be 11.26%, which may be ascribed to the efficient energy transfer from the PFO host to the MDMO-PPV guest material.     

溶胶／凝胶法制备纳米TiO2／Al2O3

采用溶胶-凝胶法制备纳米TiO2／Al2O3，考察了陈化温度及络舍比对TiO2／Al2O3比表面积及孔结构参数的影响。结果表明，TiO2／Al2O3平均粒径〈70nm，比表面积超过210m^2／g，平均孔径0．8-1．4nm。适当降低陈化温度及加络合剂有利于TiO2／Al2O3粒子的分散。Al2O3的存在提高了TiO2／Al2O3的热稳定性。     

Green electroluminescent device with a terbium β-diketonate complex as emissive center

In this study, a terbium complex, Tb(acac)₃bath (acac: acetylacetone, bath: 4,7-diphenyl-1,10-phenanthroline), was synthesized and its luminescent properties were investigated compared with the reported terbium complex, Tb(acac)₃phen (phen: phenanthroline). When it was used as an emitting material in organic electroluminescent (EL) device, the triple-layer-type device with a structure of glass substrate/ITO (indium-tin oxide)/TPD (N,N^′-diphenyl-N,N^′-bis(3-methylphenyl)-1,1^′-biphenyl-4,4^′-diamine)/Tb(acac)₃bath/Alq₃ (tris (8-hydroxyquinolinato) aluminum)/Al (aluminum) exhibited bright characteristic emission of terbium ion upon applying DC voltage. An apparent difference was observed between the photoluminescence spectrum and the EL spectrum. The EL device exhibited some characteristics of diode and the maximum luminance of 77 cd/m² was obtained at 17 V.     

Synthesis and light-emitting properties of poly[9-(4′-tert-butyl-phenylenemethene)-fluoroene-co-9,9-dioctylfluorene]

A novel copolymer, poly[9-(4′-tert-butyl-phenylenemethene)-fluoroene-co-9,9-dioctylfluorene], has been synthesized through the Yamamoto coupling method. The copolymer has good solubility and thermal stability with a glass transition temperature at 85 °C. The PL spectrum of the copolymer shows a maximum emission peak at 530 nm. A polymer light-emitting diode (PLED) with the configuration ITO/PEDOT/copolymer/Ca/Al has been fabricated. The device emits green light with an emission peak at 540 nm. A maximum brightness of 603 cd/m² was achieved at a drive voltage of 24.3 V.     

Laser-induced forward transfer of polymer light-emitting diode pixels with increased charge injection

Laser-induced forward transfer (LIFT) has been used to print 0.6 mm × 0.5 mm polymer light-emitting diode (PLED) pixels with poly[2-methoxy, 5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as the light-emitting polymer. The donor substrate used in the LIFT process is covered by a sacrificial triazene polymer (TP) release layer on top of which the aluminium cathode and functional MEH-PPV layers are deposited. To enhance electron injection into the MEH-PPV layer, a thin poly(ethylene oxide) (PEO) layer on the Al cathode or a blend of MEH-PPV and PEO was used. These donor substrates have been transferred onto both plain indium tin oxide (ITO) and bilayer ITO/PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) blend) receiver substrates to create the PLED pixels. For comparison, devices were fabricated in a conventional manner on ITO substrates coated with a PEDOT:PSS hole-transporting layer. Compared to multilayer devices without PEO, devices with ITO/PEDOT:PSS/MEH-PPV:PEO blend/Al architecture show a 100 fold increase of luminous efficiency (LE) reaching a maximum of 0.45 cd/A for the blend at a brightness of 400 cd/m(2). A similar increase is obtained for the polymer light-emitting diode (PLED) pixels deposited by the LIFT process, although the maximum luminous efficiency only reaches 0.05 cd/A for MEH-PPV:PEO blend, which we have attributed to the fact that LIFT transfer was carried out in an ambient atmosphere. For all devices, we confirm a strong increase in device performance and stability when using a PEDOT:PSS film on the ITO anode. For PLEDs produced by LIFT, we show that a 25 nm thick PEDOT:PSS layer on the ITO receiver substrate considerably reduces the laser fluence required for pixel transfer from 250 mJ/cm(2) without the layer to only 80 mJ/cm(2) with the layer.     

Synthesis of new fluorene-based copolymers containing an anthracene derivative and their applications in polymeric light-emitting diodes

We report the synthesis of copolymers containing fluorene and highly soluble anthracene derivatives, of general formula, poly{9,9'-bis-(4-octoloxy-phenyl)-fluorene-2,7-diyl-co-9,10-bis-(decy-1-ynyl)-anthracene-2,6-diyl}s (PFAnts). The PFAnts were synthesized via Suzuki coupling and the feed ratios of the anthracene derivative (Ant) were 1, 5, 10, 30, and 50 mol % of the total amount of monomer. PFAnts showed well-defined high molecular weights and were more soluble in conventional organic solvents. The photoluminescence spectra of PFAnts shifted to longer wavelengths with increases in Ant proportion and the PFAnts emitted various colors varying from greenish-blue to orange. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels trended toward enhanced hole and electron recombination balance as the Ant proportion increased, due to the better electron-accepting ability of the anthracene moiety compared to the fluorene moiety. Polymeric light-emitting diodes with the configurations ITO/PEDOT:PSS(40 nm)/polymer(60 nm)/Ca(10 nm)/Al(100 nm) (Device A) and ITO/PEDOT:PSS(40 nm)/polymer(60 nm)/Balq(40 nm)/LiF(1 nm)/Al(100 nm) (Device B) were fabricated using the polymers as emissive layers. Especially, Device B with PFAnt01 exhibited the highest measured maximum brightness of 1760 cd/m2 at 14 V, a maximum current efficiency of 1.66 cd/A, and a maximum external quantum efficiency of 0.70%.