Printable cross-linked polymer blend dielectrics. Design strategies, synthesis, microstructures, and electrical properties, with organic field-effect transistors as testbeds

We report here the synthesis and dielectric properties of optimized, cross-linked polymer blend (CPB) dielectrics for application in organic field-effect transistors (OFETs). Novel silane cross-linking reagents enable the synthesis of CPB films having excellent quality and tunable thickness (from 10 to approximately 500 nm), fabricated both by spin-coating and gravure-printing. Silane reagents of the formula X 3Si-R-SiX 3 (R = -C 6H 12- and X = Cl, OAc, NMe 2, OMe, or R = -C 2H 4-O-C 2H 4- and X = OAc) exhibit tunable reactivity with hydroxyl-containing substrates. Dielectric films fabricated by blending X 3Si-R-SiX 3 with poly(4-vinyl)phenol (PVP) require very low-curing temperatures ( approximately 110 degrees C) and adhere tenaciously to a variety of FET gate contact materials such as n (+)-Si, ITO, and Al. The CPB dielectrics exhibit excellent insulating properties (leakage current densities of 10 (-7) approximately 10 (-8) A cm (-2) at 2.0 MV/cm) and tunable capacitance values (from 5 to approximately 350 nF cm (-2)). CPB film quality is correlated with the PVP-cross-linking reagent reactivity. OFETs are fabricated with both p- and n-type organic semiconductors using the CPB dielectrics function at low operating voltages. The morphology and microstructure of representative semiconductor films grown on the CPB dielectrics is also investigated and is correlated with OFET device performance.     

Microcontact-printed self-assembled monolayers as ultrathin gate dielectrics in organic thin-film transistors and complementary circuits

We have developed a manufacturing process for organic thin-film transistors and organic complementary circuits in which a microcontact-printed phosphonic acid self-assembled monolayer is employed first as an etch resist to pattern aluminum gate electrodes by wet etching and then as the gate dielectric of the same device. To our knowledge, this is the first report of a printing process for electronic devices that combines the concepts of direct and indirect printing in the same printing step and for the same material by employing a transferred pattern both as an etch resist (indirect printing) and as a functional material as part of the final device (direct printing). Owing to the small thickness and the high quality of the monolayer gate dielectric, the transistors and circuits operate at a low voltage of 3 V.     

基于含硫芳杂稠环化合物的可溶性共轭齐聚物的合成、表征及其在有机薄膜晶体管中的应用

设计并合成了4个基于含硫芳杂稠环化合物的可溶性共轭齐聚物,即以3-十一烷基苯并[d,d’]噻吩并[3,2-b;4,5-b ’]并二噻吩(BTTT)为末端芳香单元,噻吩(T)、二噻吩(bT)、N-十二烷基-二噻吩并[3,2-b]吡咯(TP)或2,5-双(3-十二烷基噻吩)[3,2-b]并二噻吩 (qT)为中间芳香单元的...     

Thermally curable organic/inorganic hybrid polymers as gate dielectrics for organic thin‐film transistors

New low‐temperature curable organic/inorganic hybrid polymers were designed and synthesized as gate dielectrics for organic thin‐film transistors (OTFTs). Allyl alcohols were introduced to polyhedral oligomeric silsesquioxane (POSS) via hydrosilyation to produce an alcohol‐functionalized POSS derivative (POSS‐OH). POSS‐OH was then reacted with hexamethoxymethylmelamine at carrying molar ratios at 80 °C in the presence of a catalytic amount of p‐toluenesulfonic acid to give highly cross‐linked network polymers (POSS‐MM). The prepared thin films were smooth and hard after the thermal cross‐linking reaction and had very low leakage currents (<10^?8 A/cm²) with no significant absorption over the visible spectral range. Pentacene‐based OTFTs using the synthesized insulators as gate dielectric layers had higher hole mobilities (up to 0.36 cm²/Vs) than a device using thermally cross‐linked poly(vinyl phenol) and melamine as the gate dielectric layer (0.18 cm²/Vs). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3260–3268     

Nano-floating gate memory based on ZnO thin-film transistors and Al nanoparticles

In this study, nonvolatile nano-floating gate memory devices were fabricated based on ZnO films and Al nanoparticles and their electrical properties were investigated. Al nanoparticles were embedded in between SiO₂ tunneling and control oxide layers deposited on ZnO channels, and these nanoparticles acted as floating gate nodes in the devices. Their electron mobility, on/off ratio, and threshold voltage shift were estimated to be 9.42 cm²/V s, about 10⁶, and 4.2 V, respectively. Their programming/erasing, endurance and retention were also characterized. Especially, the low-temperature processes applied in this work indicate that integrated electronic devices can be fabricated on temperature-sensitive substrates.     

Design and properties of functional hybrid organic-inorganic membranes for fuel cells

This critical review presents a discussion on the major advances in the field of organic-inorganic hybrid membranes for fuel cells application. The hybrid organic-inorganic approach, when the organic part is not conductive, reproduces to some extent the behavior of Nafion where discrete hydrophilic and hydrophilic domains are homogeneously distributed. A large variety of proton conducting or non conducting polymers can be combined with various functionalized, inorganic mesostructured particles or an inorganic network in order to achieve high proton conductivity, and good mechanical and chemical properties. The tuning of the interface between these two components and the control over chemical and processing conditions are the key parameters in fabricating these hybrid organic-inorganic membranes with a high degree of reproducibility. This dynamic coupling between chemistry and processing requires the extensive use and development of complementary ex situ measurements with in situ characterization techniques, following in real time the molecular precursor solutions to the formation of the final hybrid organic-inorganic membranes. These membranes combine the intrinsic physical and chemical properties of both the inorganic and organic components. The development of the sol-gel chemistry allows a fine tuning of the inorganic network, which exhibits acid-based functionalized pores (-SO(3)H, -PO(3)H(2), -COOH), tunable pore size and connectivity, high surface area and accessibility. As such, these hybrid membranes containing inorganic materials are a promising family for controlling conductivity, mechanical and chemical properties (349 references).     

超分子化合物(C10N2H9)3[PMo12O40]·3H2O合成与表征

利用水热方法合成了超分子化合物(C10N2H9)3[PMo12O40]·3H2O,通过元素分析、ICP和X射线单晶衍射确定了其晶体结构,并通过IR和XRD进行了结构表征,采用热重分析和循环伏安曲线研究了晶体的热稳定性和氧化还原性．该化合物是由联吡啶、水以及[PMo12O40]3-阴离子组成,它们之间存在较强的氢键作用,自组装成超分子结构化合物．     

Synthesis, structure, and dynamic properties of hybrid organic-inorganic rotaxanes

The synthesis and characterization of a series of hybrid organic-inorganic [2]rotaxanes is described. The ring components are heterometallic octa- ([Cr(7)MF(8)(O(2)C(t)Bu)(16)]; M = Co, Ni, Fe, Mn, Cu, Zn, and Cd) nuclear cages in which the metal centers are bridged by fluoride and pivalate ((t)BuCO(2)(-)) anions; the thread components feature dialkylammonium units that template the formation of the heterometallic rings about the axle to form the interlocked structures in up to 92% yield in conventional macrocyclization or one-pot 'stoppering-plus-macrocyclization' strategies. The presence in the reaction mixture of additives (secondary or tertiary amines or quaternary ammonium salts), and the nature of the stoppering groups (3,5-(t)Bu(2)C(6)H(3)CO(2)- or (t)BuCONH-), can have a significant effect on the rotaxane yield. The X-ray crystal structures of 11 different [2]rotaxanes, a pseudorotaxane, and a two-station molecular shuttle show two distinct types of intercomponent hydrogen bond motifs between the ammonium groups of the organic thread and the fluoride groups of the inorganic ring. The different hydrogen bonding motifs account for the very different rates of dynamics observed for the heterometallic ring on the thread (shuttling slow; rotation fast).     

Molecular design of hybrid organic-inorganic materials with electronic properties

The synthesis of two classes of hybrid organic-inorganic nanocomposites with electronic properties is reported. One is made of PDMS units cross linked with vanadium oxo-species where the vanadium coordination depends on the hydrolysis pH. Tetrahedral coordination is retained at neutral pH, while acidic conditions promote the segregation of five coordinated vanadium oxo-species. The reduction process depends also on the vanadium coordination. The second system is made of siloxane T units and polypyrrole oligomers, grafted and interpenetrated at a nano size level.     

Solution-processed organic field-effect transistors and unipolar inverters using self-assembled interface dipoles on gate dielectrics

Self-assembled monolayers (SAMs) of polarized and nonpolarized organosilane molecules on gate insulators induced tunable threshold voltage shifting and current modulation in organic field-effect transistors (OFETs) made from solution-deposited 5,5'-bis(4-hexylphenyl)-2,2'-bithiophene (6PTTP6), defining depletion-mode and enhancement-mode operation. p-Channel inverters were made from pairs of OFETs with an enhancement-mode driver and a depletion-mode load to implement full-swing and high-gain organic logic circuits. The experimental results indicate that the shift of the transfer characteristics is governed by the built-in electric field of the SAM. The effect of surface functional groups affixed to the dielectric substrate on the grain appearance and film mobility is also determined.     

Hexamethylenetetramine directed synthesis and properties of a new family of alpha-nickel hydroxide organic-inorganic hybrid materials with high chemical stability

A new family of organic-inorganic hybrid material of alpha-nickel hydroxide formulated as Ni(OH)2-x(An-)x/n-(C6H12N4)y.zH2O (A=Cl-, CH3COO-, SO4(2-), NO3-; x=0.05-0.18, y=0.09-0.11, z=0.36-0.43) with high stability and adjustable interlayer spacing ranging from 7.21 to 15.12 A has been successfully prepared by a simple hydrothermal method. The effects of various anions and hexamethylenetetramine (HMT) on the d values of alpha-nickel hydroxide have been systematically investigated. This family of hybrid materials is of such high stability that they can stand more than 40 days in 6 M KOH. The product with a formula Ni(OH)1.95(C6H12N4)0.11(Cl-)0.05(H2O)0.36 has a high surface area of about 299.26 m2/g and an average pore diameter of about 45.1 A. The coercivity (Hc) value is ca. 2000 Oe for the sample with a d spacing of 13.14 A. Moreover, the prepared alpha-Ni(OH)2 in our experiment is of high stability in strong alkali solution. Such high stability could be derived from strong chelating interactions between the Ni ions and HMT molecules with the interlayers. This high chemical stability could make this material more suitable for the applications.     

一种钴-取代型有机-无机杂化三维超分子多酸:合成、结构与表征

在水热条件下,成功合成了一例过渡金属钴修饰的有机-无机杂化Dawson型三维超分子多金属磷钨酸簇合物[Co(dap)_3]_2[H_2P_2W_(18)O_(62)]·11H_2O (1)(dap=1,2-丙二胺),采用X射线单晶衍射、元素分析、红外光谱及热重分析对化合物进行了结构分析和基本表征.化合物1属于正交晶系,Pnma空间群,单胞参数为a=2.688 92(7) nm,b=2.176 67(6) nm,c=1.480 93(5) nm,α=β=γ=90°.从超分子化学的角度来看,化合物1中的饱和Dawson型簇阴离子和金属-有机复合物之间通过广泛的氢键作用,进而形成有趣的4,8-连接的三维超分子网络结构.     

Controllable synthesis of organic-inorganic hybrid MoOx/polyaniline nanowires and nanotubes

A novel chemical oxidative polymerization approach has been proposed for the controllable preparation of organic-inorganic hybrid MoO(x)/polyaniline (PANI) nanocomposites based on the nanowire precursor of Mo(3)O(10)(C(6)H(8)N)(2)·2H(2)O with sub-nanometer periodic structures. The nanotubes, nanowires, and rambutan-like nanoparticles of MoO(x)/PANI were successfully obtained through simply modulating the pH values to 2.5-3.5, ≈2.0 and ≈1.0, respectively. Through systematic physicochemical characterization, such as scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and so forth, the composition and structure of MoO(x)/PANI hybrid nanocomposites are well confirmed. It is found that the nanowire morphology of the precursor is the key to achieve the one-dimensional (1D) structures of final products. A new polymerization-dissolution mechanism is proposed to explain the formation of such products with different morphologies, in which the match between polymerization and dissolution processes of the precursor plays the important role. This approach will find a new way to controllably prepare various organic-inorganic hybrid 1D nanomaterials especially for polymer-hybrid nanostructures.     

Hexathiapentacene: structure, molecular packing, and thin-film transistors

In this communication we report the electrical characteristics of hexathiapentacene (HTP) and emphasize the unusual chemical structure and molecular packing. We report field-effect mobilities as high as 0.04 cm2 V-1 s-1 and current on/off ratios of >105. With crystallographic evidence of unusually long S-S bonds compared to normal S-S bonds, we have suggested a unique resonance structure similar to trithiapentalene, which well explains the bonding characteristics of HTP. This work appears to be the first to determine its molecular structure/packing mode and to study its application in organic transistors.     

Enantioselective synthesis induced by chiral organic-inorganic hybrid silsesquioxane in conjunction with asymmetric autocatalysis

5-Pyrimidyl alkanol with up to 96% ee was formed using chiral organic-inorganic hybrid silsesquioxane in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, in conjunction with asymmetric autocatalysis.     

One-step synthesis of organic-inorganic hybrid asymmetric dimer particles via miniemulsion polymerization and functionalization with silver

Organic-inorganic polystyrene (PSt)-silica (SiO2) hybrid asymmetric particles were prepared in one step by a miniemulsion polymerization technique. The organic and inorganic reagents were confined in miniemulsion microreactor droplets. After the formation of PSt and SiO2, internal phase separation inside the droplets was accelerated owing to the hydrophobicity of PSt and the hydrophilicity of SiO2. Therefore, PSt-SiO2 hybrid asymmetric particles could be synthesized in one step. Between each pair of asymmetric particles, silane couplers act as bridges connecting the PSt and SiO2 particles. The size of PSt particles in these asymmetric particles was easily tuned either by changing the weight ratio of St/TEOS or by varying the sonication power during the miniemulsion preparation. After functionalization of the as-prepared asymmetric dimers by surface decoration with Ag particles, enhanced surface-enhanced Raman scattering (SERS) properties were observed due to electromagnetic enhancement of the added Ag colloids.     

Floating-potential dielectrophoresis-controlled fabrication of single-carbon-nanotube transistors and their electrical properties

We present a floating-potential dielectrophoresis method used for the first time to achieve controlled alignment of an individual semiconducting or metallic single-walled carbon nanotube (SWCNT) between two electrical contacts with high repeatability. This result is significantly different from previous reports, in which bundles of SWCNTs were aligned between electrode arrays by a conventional dielectrophoresis process where the results were only collected from the control electrode regions. In this study, our alignment focus is not only on the regions of the control electrodes but also on those of the floating electrodes. Our results indicate that bundles of carbon nanotubes along with impurities were first moved into the region between two control electrodes while individual nanotubes without impurities were straightened and aligned between two floating electrodes. The measurements for the back-gated nanotube transistors made by this method displayed an on-off ratio and transconductance of 10(5) and 0.3 microS, respectively. These output and transport properties are comparable with those of nanotube transistors made by other methods. Most importantly, the findings in this study show an effective way to separate individual nanotubes from bundles and impurities and advance the processes for site-selective fabrication of single-SWCNT transistors and related electrical devices.     

Synthesis, characterization, and photochromic properties of hybrid organic-inorganic materials based on molybdate, DABCO, and piperazine

Prompted by our interest in new photochromic organic-inorganic hybrid materials, the reactivity of [Mo7O24]6- toward a structure-directing reagent diamine such as 1,4-diazabicyclo[2.2.2]octane (DABCO) and piperazine (pipz) has been investigated, and three new molybdenum(VI)-containing compounds, namely, (H2DABCO)3[Mo7O24].4H2O (1), (H2DABCO)[Mo3O10].H2O (2), and (H2DABCO)2(NH4)2[Mo8O27].4H2O (3), have been synthesized and characterized. New synthetic routes to achieve the known compounds (H2DABCO)2(H2pipz)[Mo8O27] (4), (H2pipz)3[Mo8O27] (5), and (H2DABCO)2[Mo8O26].4H2O (6) are also reported. All of these compounds contain different poly(oxomolybdate) clusters, i.e., discrete [Mo7O24]6- blocks in 1, infinite polymeric chains 1/infinity[Mo3O10]2- in 2, 1/infinity[Mo8O27]6- in 3-5, and 1/infinity[Mo8O26]4- in 6, associated in a tridimensional assembly by hydrogen bonds with H2DABCO2+ and/or H2pipz2+ cations. Interconversion pathways and chemical factors affecting the stabilization of the different species are highlighted and discussed. At the opposite of 6, compounds 1-5 show photochromic behavior under UV excitation. Namely, compounds 1-5 shift from white or pale yellow to pale pink, reddish brown, or purple under UV illumination depending on the chemical nature of the mineral framework, with the kinetics of the color change being dictated by the nature of the organic component and by the organic-inorganic interface.     

A one-pot method for controlled synthesis and selective etching of organic-inorganic hybrid perovskite crystals

Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH_3NH_3PbBr_3 single crystals with the lateral size of 100 μm and the thickness of 3–8 μm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique,CH_3NH_3PbBr_3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser,optical sensors, photodetectors and field effect transistors.