喷墨打印PVP绝缘层柔性薄膜晶体管研究

柔性电子设备的快速发展对薄膜晶体管(TFT)提出了低功耗、耐弯折和可低温制备的要求.其中,栅极绝缘层是核心材料之一.溶液法制备有机栅极绝缘层具有低成本、柔韧性强的优点,适合大面积加工.本文采用喷墨打印法实现了聚乙烯吡咯烷酮(PVP)墨水的印刷成膜,采用XPS分析了不同退火温度处理的印刷PVP薄膜成分差异,并测试了PVP...     

4-(4-乙烯基苯基)苯甲酸-(-4乙烯基)苯酯的合成

以联苯为原料,经傅克酰化、溴代、格氏和氧化反应,制备了4-(4-乙酰基苯基)苯甲酸;以苯甲醚为原料经傅克酰化,醚解制备了4-乙酰基苯酚;两者再经酯化、还原、脱水反应,合成了一种新型的双官能团聚合物材料单体4-(4-乙烯基)苯基苯甲酸-(4-乙烯基)苯酯,基于联苯的总收率为7%～10%,其结构经1 H NMR和FT-IR确认,并用偏光显微镜和差示扫描量热仪对其液晶性进行了研究。     

喷墨打印像素化蓝光OLED器件

喷墨打印作为一种工序简单、低成本、无掩模、非接触、承印基板和墨水材料选择广的数字化制备工艺,广泛应用于多种领域.利用喷墨打印技术,以PEDOT∶PSS为空穴注入层,PF-SO为发光层,并蒸镀Ba和Al电极,实现像素化蓝光OLED器件的制备.通过精确调控打印喷头驱动参数调整墨滴喷射特性,并调控墨水张力、粘度等参数,获得平...     

有机薄膜晶体管直流电流-电压模型的研究

通过对有机薄膜晶体管(OTFT)电流-电压特性的研究,建立了一种用于电路模拟的仿真程序(SPICE)的OTFT直流电流-电压模型,所用的参数都可从实验特性曲线中提取。对一种基于并五苯(Pentacene)的底栅顶接触(TC)结构的OTFT的实验曲线进行参数提取,并利用所得的参数与建立的模型进行仿真,得到的输出特性和转移特性曲线与实验结果无论在线性区还是在饱和区都具有较强的一致性,验证了本文所建模型及参数的准确性。建立的模型能够准确描述OTFT的直流特性,可用于有机电路的SPICE仿真。     

基于喷墨打印的In2 O3/IGZO TFT的电学性能

利用喷墨打印技术制备了非晶铟镓锌氧化物(IGZO)薄膜、铟氧化物(In_2O_3)薄膜和性能明显改善的双层In_2O_3/IGZO异质结沟道薄膜,研究了薄膜的物理与电学特性。结果表明,喷墨打印制备的金属氧化物薄膜具有较高的光学透过率与较低的表面粗糙度;嵌入的In_2O_3层薄膜能减小IGZO与In_2O_3间的界面缺陷,明显提高In_2O_3/IGZO薄膜晶体管(TFT)的性能及其偏压稳定性。随着IGZO中In含量的增加,载流子浓度升高,器件的迁移率增大,但In_2O_3与IGZO间能级势垒会逐渐降低,最后导致难以控制关态电流和阈值电压,因此,适当调整In的比例有利于获得较高器件性能的In_2O_3/IGZO异质结沟道TFT。     

一步法合成4-(反式-4''''-正戊基环己基)环己酮

以较少量(质量分数4%)的国产商品化钯/炭为催化剂,在温度160℃,压力0.60～O.70 MPa条件下,由4-(反式-4'-正戊基环己基)苯酚加氢合成了4-(反式-4'-正戊基环己基)环己酮,酚的转化率为97.1%,酮的选择性为85.5%,加以高锰酸钾氧化进行后处理,少量原料酚可直接氧化去除,醇则氧化为目标酮,总收率85.2%.该反应体系催化剂用量较少,且安全与环保.     

聚(3,4-乙撑二氧噻吩)的二次掺杂改性研究

利用乙二醇(EG)对聚(3,4-乙撑二氧噻吩)(PEDOT)进行二次掺杂改性,考察了二次掺杂PEDOT薄膜的电学性能、表面形貌和分子组成,并且对PEDOT的二次掺杂改性机理进行了探讨.研究发现,未进行二次掺杂时,PEDOT导电颗粒因被绝缘的聚苯磺酸(PSS)包埋而不能彼此接触,电荷在PEDOT薄膜中的传导由隧道效应占主导,薄膜的电导率较低.二次掺杂后,PEDOT与PSS发生相分离,同时PSS的相对含量降低,PEDOT导电颗粒问形成导电通道,薄膜的电导率较高.     

化学合成聚(3-甲基噻吩)及其在超电容器中的应用

以FeCl3为氧化剂,用化学氧化法制得了聚(3-甲基噻吩)粉末,此法操作简单且产量高。由此得到的活性物质与乙炔黑、偏氟乙烯-六氟丙烯共聚物(P(VDF-HFP))混合制成复合电极。按复合电极中的活性物质含量计算时,其单电极比容量可达260 F/g 。     

Cr∶Mg_2SiO_4晶体中络离子(CrO_4)~(4-)的自旋极化MS-X_α计算

本文采用自旋极化MS-X_α方法计算了Cr:Mg_2SiO_4晶体中络离子(CrO_4)~(4-)的电子结构,给出了T_d群和C_(3v)群下的单电子能量本征值、本征函数和自旋极化分裂值。用过渡态理论计算了部分光学跃迁和电荷转移跃迁的能量。采用Case-Karplus电荷分配法计算得到自旋-轨道耦合常数ζ_(?)。讨论了配位体的距离对单电子轨道和基态组态的影响,也讨论了对称性变化的影响。     

可溶性聚(2,5-二己氧基)对苯乙炔三阶非线性光学特性

报道了利用脱氯化氢反应制备可溶性聚(2,5二己氧基)对苯乙炔(PDHOPV),这种聚对苯乙炔(PPV)衍生物在波长450～550nm范围内具有强的光学吸收,最大吸收峰位于499nm处。采用简并四波混频(DFWM)技术对PDHOPV薄膜的非线性光学特性进行研究。结果表明:PDHOPV具有大的三阶非线性光学特性;激发波长为532nm的共振三阶非线性系数和1.064μm的非共振三阶非线性系数分别为9.6×10-10esu和2.1×10-11esu;电子共振增强有利于提高三阶非线性光学系数。     

喷墨印刷制备有机薄膜晶体管及其电路的研究进展

有机薄膜晶体管在大面积柔性显示、柔性电子存储等方面具有广阔的潜在应用前景。喷墨印刷技术由于具有工艺简单、成本低廉、微图形数字化、与柔性衬底兼容等优点而成为一种有效的制造有机电子器件工艺方法。文章综述了近年来基于喷墨印刷技术制备有机薄膜晶体管的研究进展,探讨了在制造过程中存在的问题。     

Influence of Dielectric Surface Chemistry on the Microstructure and Carrier Mobility of an n‐Type Organic Semiconductor

This paper examines the microstructure evolution of 3,4,9,10‐perylene‐tetracarboxylic bis‐benzimidazole (PTCBI) thin films resulting from conditions imposed during film deposition. Modification of the silicon dioxide interface with a hydrophobic monolayer (octadecyltrichlorosilane (OTS‐18)) alters the PTCBI growth habit by changing the unit cell contact plane. PTCBI films deposited on oxide surface have an orientation of (011), while films atop OTS‐treated oxide surface have a preferred orientation of (001). The quality of the self assembled monolayer does not appear to influence the PTCBI growth preference significantly yet it enhances the carrier mobility, suggesting that charge traps are adequately passivated due to uniform monolayer coverage. High‐quality monolayers result in n‐type carrier mobility values of 0.05 cm²V^–1s^–1 Increasing the substrate temperature during PTCBI film deposition correlates with an increase in mobility that is most significant for films deposited on OTS‐treated surface.     

Underlying Mechanism of Inkjet Printing of Uniform Organic Semiconductor Films Through Antisolvent Crystallization

An underlying mechanism is reported for the formation of highly uniform crystalline organic semiconductor films by the double‐shot inkjet printing (IJP) technique utilizing antisolvent crystallization. It is demonstrated that the ability to form uniform films with this technique can be attributed to the unique nature of the initial contact dynamics between the chemically different microdroplets before occurrence of solute crystallization. Experiments are conducted systematically where a single microdroplet is over‐deposited by the IJP technique on a chemically different sessile droplet, for ten kinds of pure and miscible solvent combinations. The subsequent behavior is observed by high speed camera. The initial contact dynamics can be classified into three dramatically different cases that are respectively referred to as wetting, dewetting, and sinking. These phenomena are unique to microdroplets and the conditions for the occurrence of each type of phenomenon can be consistently explained by the fact that the initial contact dynamics are driven by the difference of surface tension of the liquids. Among the three kinds of dynamics, the wetting phenomenon creates a thin solution layer on the antisolvent droplet surface and can be used thus to manufacture uniform semiconductor films, where the coffee ring effect can be eliminated.     

TiO2-poly(4-vinylphenol) nanocomposite dielectrics for organic thin film transistors

We report on the fabrication of organic thin film transistors (OTFTs), which operate at low voltages, by incorporating a nanocomposite gate insulator material consisting of titania (TiO₂) nanoparticles used as fillers and poly(4-vinyl phenol) (PVP) used as matrix. The surface of the nanoparticles was modified by the ligands, 4-hydroxybenzoic acid, to enhance their compatibility with the polymer. The structure of the ligand is similar to that of the repeat units in the polymer. Once the nanoparticles were homogeneously dispersed in the polymer matrix, they were immobilized by cross-linking PVP with poly(melamine-co-formaldehyde) methylated/butylated (cross-linker). Consequently, no significant aggregation of the nanoparticles, even at a concentration of 31 wt%, was found in the nanocomposites, as observed by transmission electron microscopy (TEM). As a result, the nanocomposite exhibited a low leakage current density (∼10⁻⁸ A/cm⁻²). With an increase in the concentration of TiO₂ nanoparticles added, the dielectric constant of the nanocomposites also increased proportionately as compared to that of pristine PVP. The performance of the OTFTs in terms of the charge carrier mobility, on/off ratio, threshold voltages, and hysteresis was evaluated. In addition, the relationship between the concentration of TiO₂ nanoparticles and the device performance is discussed in detail.     

Molecular subtractive surface-energy engineering of crosslinked Poly(4-vinylphenol) insulators for a solution-processed organic thin-film transistor

We propose a feasible method of manipulating the surface energy of crosslinked poly(4-vinylphenol) (c-PVP) thin films through the surface compositional modification assisted by an etchant. A physical picture of the surface-energy manipulation of c-PVP thin films based on the surface-selective molecular subtractive approach is clarified by investigating the chemical composition of the c-PVP film surfaces. We reveal that the molecular detachment by solvation on the surface leads to a reduction in the surface PVP density, thereby decreasing residual hydroxyl groups on the surface. In particular, it is found that the surface energy of a c-PVP thin film can be controlled by exploiting the thermal-treatment-time dependence of the soluble-PVP density. Organic thin-film transistors (TFTs) are fabricated via a solution process for demonstrating the applicability of our surface-energy-engineered c-PVP film as a gate insulator. The TFTs with the engineered c-PVP gate insulators exhibit improved electrical characteristics, compared to those with ordinary c-PVP gate insulators.     

A low voltage and small hysteresis C_(60) thin film transistor

Organic thin film transistors with C_(60) as an n-type semiconductor have been fabricated.A tantalum pentoxide(Ta_2O_5)/poly-methylmethacrylate(PMMA) double-layer structured gate dielectric was used.The Ta_2O_5 layer was prepared by using a simple solution-based and economical anodization technique.Our results demonstrate that double gate insulators can combine the advantage of Ta_2O_5 with high dielectric constant and polymer insulator for a better interface with the organic semiconductor.The performanc...     

有源层厚度对CuPc-OTFT器件性能的影响

研究了不同厚度有源层的顶电极CuPc-OTFT器件的电学特性。发现器件的性能与有源层厚度有依赖关系，其中，有源层厚度为20nm的器件性能最好。在有源层厚度大于20nm时，有源层厚度的增大不但分去一部分栅电压而且还增大了源、漏电极的接触电阻，从而不利于器件性能的提高。但当有源层厚度小于20nm以后器件的性能开始降低。我们认为当有源层厚度降低到一定程度时，有源层上表面的表面态会使有机材料的隙态浓度增加从而对沟道载流子迁移率产生不良影响以及使器件的阈值电压增大。     

Patterning Liquid Crystalline Organic Semiconductors via Inkjet Printing for High-Performance Transistor Arrays and Circuits

Liquid crystalline (LC) organic semiconductors having long-range-ordered LC phases hold great application potential in organic field-effect transistors (OFETs). However, to meet real device application requirements, it is a prerequisite to precisely pattern the LC film at desired positions. Here, a facile method that combines the technique of inkjet printing and melt processing to fabricate patterned LC film for achieving high-performance organic integrated circuits is demonstrated. Inkjet printing controls the deposition locations of the LC materials, while the melt processing implements phase transition of the LC materials to form high-quality LC films with large grain sizes. This approach enables to achieve patterned growth of high-quality 2,7-dioctyl[1]-benzothieno[3,2-b][1]benzothiophene (C₈-BTBT) LC films. The patterned C₈-BTBT LC film-based 7 × 7 OFET array has 100% die yield and shows high average mobility of 6.31 cm² V⁻¹ s⁻¹, along with maximum mobility up to 9.33 cm² V⁻¹ s⁻¹. As a result, the inverters based on the patterned LC films reach a high gain up to 23.75 as well as an ultrahigh noise margin over 81.3%. Given the good generality of the patterning process and the high quality of the resulting films, the proposed method paves the way for high-performance organic integrated devices.     

喷墨打印技术在PCB中的应用（上）

无论从PCB产品的简化生产工序、缩短生产周期和降低成本上,还是在节能减排、降耗增效的环境保护方面,数字喷墨打印技术在PCB领域应用中的优点是明显的。但是在PCB高端或高密度化的产品方面,喷墨打印技术在PCB中的应用还有关键的工艺技术有待突破,如喷射皮升级油墨小滴的喷头,喷印油墨（特别是提供金属“纳米”级的高端油墨）等。然而,随着喷墨打印技术的深入发展与进步,在PCB生产领域中,它会占有一定的份额、甚至会成为PCB生产的主流。