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Semiconducting Layer (semiconducting + layer)

Distribution by Scientific Domains
Polymers and Materials Science80%

Selected Abstracts

Molecular Ordering of High-Performance Soluble Molecular Semiconductors and Re-evaluation of Their Field-Effect Transistor Characteristics,

ADVANCED MATERIALS, Issue 18 2008
Takafumi Izawa
Intermolecular hydrophobic interactions between long alkyl chains (fastener effect) can enhance the intermolecular overlap of the semiconducting layer of 2,7-dialkyl[1]benzothieno[3,2- b][1]benzothiophenes (Cn -BTBTs; n,=,8, 10, 12), which contributes to improvements of the electric characteristics of their organic field-effect transistors. The molecular ordering of Cn -BTBTs in the thin-film state is elucidated by means of in-plane and out-of-plane X-ray diffraction of spin-coated thin films, and single crystal X-ray analysis. [source]

Field-effect transistors based on PPV derivatives as a semiconducting layer

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009
Woo-Hyung Lee
Abstract A series of modified thiophene groups containing PPV-based semiconducting materials, poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(2,2,bithienylenevinylene)] (PPBT), poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(5,5-thiostilylenevinylene)] (PPTVT), have been synthesized through a Horner coupling reaction. From the FTIR and 1H NMR spectroscopy, the configuration of the vinylene groups in the polymers was all trans (E) geometry. The weight-average molecular weights (Mw) of PPBT and PPTVT were found to be 11,700 and 11,800, with polydispersity indices of 2.51 and 2.53, respectively. PPBT and PPTVT thin films exhibit UV,visible absorption maxima at 538 and 558 nm, respectively, and the strong absorption shoulder peaks at 578 and 602 nm, respectively. Solution processed field-effect transistors (FET) fabricated using all the polymers showed p -type OTFT characteristics. The field-effect mobility of the PPTVT was obtained up to 2.3 × 10,3 cm2 V,1 s,1, an on/off ratio of 1.0 × 105 with ambient air stability. Studies of the atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis of the polymer thin films revealed that all the polymers were amorphous structure. The greater planarity and rigidity of PPTVT compared to PPBT results in elongation of conjugation length and better ,,, stacking of polymer chains in amorphous region, which leads to improved FET performance. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 111,120, 2009 [source]

Ternary single-source precursors for polycrystalline thin-film solar cells

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2002
Kulbinder K. Banger
The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution for fabricating solar arrays with high specific power (W kg,1). The use of a polycrystalline chalcopyrite absorber layer for thin-film solar cells is considered as the next generation in photovoltaic devices. At NASA GRC we have focused on the development of new single-source precursors (SSPs) and their utility to deposit the chalcopyrite semiconducting layer (CIS) onto flexible substrates for solar-cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering are described. Thin-film fabrication studies demonstrate that the SSPs can be used in a spray chemical vapor deposition process for depositing CIS at reduced temperatures, and result in electrical properties that are suitable for photovoltaic devices. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Ultrathin Films of Single-Walled Carbon Nanotubes for Electronics and Sensors: A Review of Fundamental and Applied Aspects

ADVANCED MATERIALS, Issue 1 2009
Qing Cao
Abstract Ultrathin films of single-walled carbon nanotubes (SWNTs) represent an attractive, emerging class of material, with properties that can approach the exceptional electrical, mechanical, and optical characteristics of individual SWNTs, in a format that, unlike isolated tubes, is readily suitable for scalable integration into devices. These features suggest the potential for realistic applications as conducting or semiconducting layers in diverse types of electronic, optoelectronic and sensor systems. This article reviews recent advances in assembly techniques for forming such films, modeling and experimental work that reveals their collective properties, and engineering aspects of implementation in sensors and in electronic devices and circuits with various levels of complexity. A concluding discussion provides some perspectives on possibilities for future work in fundamental and applied aspects. [source]

Highly Bendable, Transparent Thin-Film Transistors That Use Carbon-Nanotube-Based Conductors and Semiconductors with Elastomeric Dielectrics,

ADVANCED MATERIALS, Issue 3 2006
Q. Cao
Transparent flexible thin-film transistors (see Figure) have been made using single-walled carbon nanotube networks of high and moderate coverages as the conducting and semiconducting layers. Electrical (e.g., good performance on plastic), optical (e.g. transparency to visible wavelengths), and mechanical (e.g. extreme flexibility) characteristics that would be difficult, or impossible, to achieve with conventional materials are reported. [source]