掺杂聚乙烯咔唑的有机二极管的伏安特性

本文提出了一种掺杂具有空穴导电特性的聚合物来改变有机二极管伏安特性的新方法。在导电玻璃上利用甩胶法分别制得两粗有机薄膜层：聚烷基噻吩和掺杂不同量聚乙烯咔唑的聚烷基噻吩。将铝沉积在这些有机薄膜上作为有二极管的负极。     

聚乙烯基咔唑掺杂低Tg体系的光折变研究

光折变效应在高密信息存取介质、相位共轭器、全息图像加工、神经网络及协同记忆的模拟、畸变图像复原等方面具有广泛的应用前景。近年来，人们对光折变新现象、新材料的研究日益深入。1991首次报道了聚合物光折变性质，由于聚合物光折变材料具有高光学非线性，低介电常数，低成本易加工等优点引起人们的极大重视。特别是1994年，H波耦合系数高达220cm‘，四波混频衍射效率高达100％的掺杂型聚合物光折变材料的报道，使得聚合物先折变的研究进入了应用的前期研究阶段。我们以电荷输运聚合物聚乙烯基咏叹（PVK）为主体掺杂生色团2，5一二甲…     

聚乙烯基咔唑对稀土络合物发光特性的影响

本文报导了稀土红色荧光络合物－Eu(TTA)m复合体系与聚乙烯基咔唑（PVK）共混体系的光致发光和电致发光性质。通过对吸收光谱和发射光谱的测量,可知在光致发光中存在PVK向Eu(TTA).复合体系的能量传递,但在较大的掺杂浓度下仍存在来自PVK的发光.在电场激发条件下,此共混体系的电致发光仅有稀土络合物的特征发光而很难看到PVK的特征发光.并且这种电致发光器件的稳定性明显改善,另外在器件结构中加入电子传输层可明显提高器件的发光效率.     

基于聚乙烯咔唑的非挥发型阻变存储特性分析

采用聚乙烯咔唑作为活性层构建了ITO/PVK/Al的三明治结构阻变存储元件,并对其阻变特性进行了测量。结果表明其具有明显的非挥发型双稳态阻变特性, 具有WORM存储特性。该元件具有良好的数据保持能力和耐久能力,开关态电流比可达103,且具有较低的阈值转换电压。分别对低阻态和高阻态的载流子传输机制进行了拟合, 低阻态为欧姆传导机制,高阻态为空间电荷限制电流发射机制。根据载流子传输机制, 对阻变特性进行了解释。     

聚合物光折变材料聚乙烯咔唑的陷阱态研究

利用热激电流(TSC)技术测量了聚合物光折变材料聚乙烯咔唑(PVK)的退极化电流曲线,获得了热激弛豫过程的活化能。发现聚乙烯咔唑材料的热激退极化电流曲线共有两个峰,低温峰位于338 K,对应的活化能约0.6 eV,高温峰位于417 K,对应的活化能范围在0.53~1.00 eV,在0.77 eV处呈现最大值,陷阱密度极大值为5.7×1013cm-3。同时证明了低温峰是源于偶极子退取向弛豫,高温峰则来自于陷阱中空穴的热释放。     

聚乙烯咔唑／铟锡氧化物的界面分析

用原子力显微镜(AFM)和X射线光电子能谱(XPS)研究了真空蒸镀聚乙烯咔唑(PVK)薄膜的表面形貌和PVK／铟锡氧化物(ITO)界面电子状态。结果表明，PVK分子虽然体积较大，但分布较均匀。XPS数据显示，在界面处PVK分子骨架和SnO2分子结构几乎没有发生变化，但PVK分子的侧基和In2O2分子结构发生了变化，因为界面处存在大量的，不能用制备过程的空气污染来解释的C-O键；在界面处，In2O3分子部分分解，所产生O原子替代PVK侧基上的H原子而形成C—O键；所产生的In原子则扩散至PVK内部。     

有机电致发光二极管中国专利申请现状分析

随着显示技术的发展,体积小、重量轻、功耗低的显示器件有机电致显示成为显示技术的发展重点,介绍了有机电致发光二极管OLED的发展历程,并以有机电致发光二极管在国内外专利申请的数据为分析样本,从有机电致发光二极管专利申请的时间、国家、技术概况等角度进行研究,分析了有机电致发光二极管的技术发展现状以及将来的发展趋势.     

多种方法研究二极管的伏安特性曲线

介绍了多种用于测量二极管伏安特性的方法,我们利用四种方法分别测量同一个二极管的电流电压值,并得出实验数据。用实验数据画出对应各个方法测得的二极管的伏安特性曲线,最后通过对四种方法测得的伏安特性曲线图做出相应的分析给出测量最为精准的方法。     

有机电致发光二极管的透明阴极的研制

介绍了利用LaB6材料制作透明有机电致发光二极管(TransparentOrganicLightEmittingDiode，TOLED)的透明阴极的特性；研究了80～250nm膜厚的透明阴极的光谱特性——在可见光范围内的透过率，其透过率在40％～70％之间，并对LaB6材料制作的透明阴极与利用Mg：Ag合金和ITO制作的透明阴极的性能进行了比较。LaB6作阴极的TOLED更利于实现高分辨率的彩色显示。     

High performance top-gate field-effect transistors based on poly(3-alkylthiophenes) with different alkyl chain lengths

The device characteristics of top-gate field-effect transistors (FETs) based on typical polymer semiconductor regioregular poly(3-alkylthiophenes) (P3ATs) with different alkyl chain lengths are investigated. High field-effect mobilities of ∼10⁻² cm²/Vs are obtained irrespective of alkyl chain length even when polymer gate insulators with different dielectric constants (2.1–3.9) are used. This is attributed to the spontaneous formation of highly ordered edge-on lamellar structures at the surface of P3AT thin films that are the channel regions in top-gate FETs. In addition, top-gate P3AT FETs containing different gate insulators exhibit high operational stability, with low threshold voltage shifts of <0.5 V following prolonged gate bias stress, which is comparable to that of hydrogenated amorphous silicon thin film transistors.     

Interplay of cleaning and de-doping in oxygen plasma treated high work function indium tin oxide (ITO)

Indium tin oxide (ITO) is extensively used as a transparent electrode in photovoltaic cells and organic light emitting diodes. High surface work function (WF) of ITO is a crucial parameter for enhanced device performance. The ITO WF is usually around 4.3 eV without any surface treatment. With surface treatments ITO WF, as high as 5.4 eV has been reported. We designed a surface treatment method with which we achieved substantially high ITO surface work function of over 6.1 eV. We observed changes in valence electronic structure and core levels, apart from surface cleaning. We also investigated interface formation of copper phthalocyanine (CuPc) on the high WF ITO. In the proximity of the interface the highest occupied energy level of CuPc was observed to be almost pinned to the Fermi level. We fabricated three simple devices with no to high treatment. The device results were observed to be consistent with the findings of electronic energy level alignment.     

Optical performance of efficient blue/near UV nitropyridine-conjugated anthracene (NAMA) based light emitting diode

9-[(5-nitropyridin-2-aminoethyl) iminiomethyl]-anthracene (NAMA) was synthesized for the first time from the reaction between 9-antracene carboxaldehyde and 2-(2-aminoethylamino)-5-nitropyridine under mild reaction conditions. The structure of the nitropyridine-conjugated anthracene (NAMA) was characterized using ¹H-NMR, ¹³C-NMR and elemental analysis techniques. Furthermore, electroluminescent behavior of the NAMA was investigated by using a material based on polycyclic aromatic hydrocarbons (PAHs) in organic light-emitting diodes (OLEDs). It was observed that the NAMA exhibits blue/near UV emission at 410 nm with a high density signal. The optimized device structure, ITO/CuPc/α−NPD/NAMA/Alq₃/LiF/Al is characterized by blue/near UV electroluminescence (EL) and a high current density with 7735 cd m⁻² maximum brightness at approximately 10.4 V. The emitting color of the device showed the blue/near UV emission (x, y) = (0.14, 0.10) at 277.1 mA cm⁻² in CIE (Commission Internationale de l’Eclairage) chromaticity coordinates with a long operational lifetime (180 h).     

稀土（Er）与氧（O）共掺GaAs（Er,O）的红外吸收谱研究

用傅里叶变换红外吸收谱和透射谱（ＦＴＩＲ），在７７Ｋ和３００Ｋ温度下测量研究用双离子注入法配合优化热退火处理制成的ＧａＡｓＥｒ，Ｏ发光材料的光吸收特性及杂质缺陷行为，观测到该材料中存在３种吸收峰并作了指认，分析了这些吸收峰与材料的离子注入及退火的关系，给出杂质和缺陷对材料ＧａＡｓ（Ｅｒ，Ｏ）高效发光的可能影响     

锗酸盐玻璃中Er3+离子Stark分裂的分析

基于群链方法提出稀土离子在玻璃基质中的表观晶格场哈密顿的简单模型 .利用该模型较为系统地分析了在 13K温度下采用常规方法测量的 Er3+离子在锗酸盐玻璃中的吸收和发射谱 ,确定了从 Er3+离子 4I1 5 /2 到 2 H9/2 所有多重态的 Stark分裂值 .     

基于混合配体Znq(DBM)的单色和白色OLED

以8-羟基喹啉(q)和1,3-二苯基-1,3-丙二酮定向合成了有机小分子配合物Znq(DBM),将其作为发光层制备了单色有机电致发光器件(OLED)。在结构为ITO/m-MTDATA(5nm)/NPB(40nm)/Znq(DBM)(60nm)/LiF(0.5nm)/Al(100nm)的器件中,启亮电压为5V,最大亮度达到4 575cd/m2。同时又在器件中引入间隔层BCP,研究其不同厚度对OLED性能的影响。在结构为ITO/m-MTDATA(5nm)/NPB(40nm)/BCP(x nm)/Znq(DBM)(60nm)/LiF(0.5nm)/Al(100nm)的器件中,当BCP层厚为0nm时,发光颜色为黄绿色;当BCP层厚为1nm时,发光颜色为白色,色坐标为(0.29,0.33),最大亮度为2 231cd/m2;当BCP层厚为5nm时,发光颜色为蓝色。根据器件结构和性能,讨论了其内部机理。     

High mobility organic field-effect transistors based on defect-free regioregular poly(3-hexylthiophene-2,5-diyl)

We report on organic field-effect transistors (OFETs) prepared using defect free (100% regioregular) poly(3-hexylthiophene-2,5-diyl) (DF-P3HT) as semiconductor and cross-linked poly(vinyl alcohol) (cr-PVA) as gate insulator. High field-effect mobility (μ_FET) of 1.2 cm² V⁻¹ s⁻¹ is obtained and attributed to the absence of regioregularity defects. These transistors have transconductance of 0.35 μS and the DF-P3HT film shows larger crystallites (∼80 Å) than a highly regioregular (>98%) material (∼32 Å). Devices with increased μ_FET (2.8 cm² V⁻¹ s⁻¹) could be obtained at the expense of the On-Off current ratio, which was reduced by one order of magnitude, when poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) treatment was applied to the dielectric surface. Our results suggest that the interaction of charged sites at the dielectric surface with regioregularity defects of the P3HT is an important factor degrading μ_FET even at very low concentration of regioregularity defects.     

Big Third-order Nonlinear Optical Properties of Two Poly[ (3-alkylthiophene-2, 5-diyl ) - ( benzylidenequinomethane-2, 5-diyi ) ] Derivatives

Two novel poly[(3-alkylthiophene-2,5-diyl)- (benzylidenequinomethane-2,5-diyl)s] derivatives,poly[ (3-butylthiophene-2,5-diyl)- ( p-N, N-dimethylamino) benzylidenequinomethane-2, 5-diyl) ] (PBTDMABQ)and poly [( 3-octylthiophene2, 5-diyl ) -( p-N, N-dimethylamino ) benzylidenequinomethane-2, 5-diyl )](POTDMABQ), were synthesized. The band gaps of the two polymers are calculated as 1. 75 eV for PBTDMABQ and 1.69 eV for POTDMABQ, respectively. The homogenous films of the two polymers were prepared and their third-order nonlinear optical properties were studied by the backward degenerate four-wave mixing at 532 nm. By using the relative measurement technique, the third-order nonlinear optical susceptibilities of PBTDMABQ and POTDMABQ are calculated as 5. 62 × 10-9 and 1. 22 × 10-8 ESU,respectively. It is found that substituted alky groups have strong effects on the band gap and nonlinear opticalproperties of the two polymers. The relatively big third-order nonlinear optical susceptibilities and small band gap of POTDMABQ resulted mainly from the longer alkyl with strong electron-donating ability can enhance the delocation degree of conjugated π electronics.     

Green- and blue-emitting tris(8-hydroxyquinoline) aluminum(III) (Alq3) crystalline polymorphs: Preparation and application to organic light-emitting diodes

Tris(8-hydroxyquinoline) aluminum(III) (Alq₃) is known to have two isomeric states, namely meridional and facial isomers. Typical Alq₃ crystals composed of meridional and facial isomers are α- and δ-form crystals, respectively. First, we investigate the temperature change in the crystalline forms of α-Alq₃ and δ-Alq₃ in X-ray diffraction experiments in a vacuum. α-Alq₃ remains in α-form up to 300 °C, immediately before sublimation. In contrast, δ-Alq₃ is found to transform into γ-form at ∼180 °C, and remain in γ-form immediately before sublimation. Both γ-Alq₃ and δ-Alq₃ are composed of facial isomers and emit blue luminescence, which is different from the typical green emissions of α-Alq₃. Second, we fabricate organic light-emitting diodes (OLEDs) from different crystals as source powders; i.e., from (1) α-Alq₃, (2) δ-Alq₃, and (3) a mixture of α-, γ-, and δ-Alq₃. All the OLEDs exhibit green electroluminescence with almost the same maximum wavelength, suggesting that some facial isomers become meridional while Alq₃ is in the gas phase. In contrast, electroluminescence efficiency depends on the Alq₃ crystalline polymorph; the OLED fabricated from the mixture of α-, γ-, and δ-Alq₃ has up to 1.4 times the efficiency of the OLED fabricated from α-Alq₃ for the same device structure.     

Estimation of hole injection barrier at the poly-3(hexylthiophene)/metal interface using accumulated charge measurement

Hole injection barriers at the regioregular-poly-3(hexylthiophene) (RR-P3HT)/metal (Cu or Ag) interface were investigated using the accumulated charge measurement (ACM). Thermal annealing of RR-P3HT at 55 °C decreased the injection barrier. RR-P3HT thermally annealed in N₂ forms an ohmic contact with Ag and a Schottky contact with Cu. The obtained values of the injection barriers, ϕ_B were well expressed by the Mott-Schottky rule, i.e., ϕ_B = IE - W_m′, where IE is the ionization energy of RR-P3HT and W_m′ is the work function of the metal electrode in air. The effect of the large vacuum level shift, reported in UPS studies conducted under ultrahigh vacuum, was not observed.