Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active thin-film organic devices are in the market place, most notably the displays of several mobile electronic appliances. Yet the future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.

The path to ubiquitous and low-cost organic electronic appliances on plastic

-phenylenevinylene)s L4. Fluorene-Based Conjugated Polymers L4.1. Fluorene-Based Copolymers ContainingElectron-Rich MoietiesM4.2. Fluorene-Based Copolymers ContainingElectron-Deﬁcient MoietiesN4.3. Fluorene-Based Copolymers ContainingPhosphorescent ComplexesQ5. Carbazole-Based Conjugated Polymers R5.1. Poly(2,7-carbazole)-Based Polymers R5.2. Indolo[3,2-

https://ir.nctu.edu.tw:443/bitstream/11536/6508/1/000271856900020.pdf

Synthesis of Conjugated Polymers for Organic Solar Cell Applications

2.2. Materials 929 2.3. Factors Influencing Charge Mobility 931 2.3.1. Molecular Packing 931 2.3.2. Disorder 932 2.3.3. Temperature 933 2.3.4. Electric Field 934 2.3.5. Impurities 934 2.3.6. Pressure 934 2.3.7. Charge-Carrier Density 934 2.3.8. Size/molecular Weight 935 3. The Charge-Transport Parameters 935 3.1. Electronic Coupling 936 3.1.1. The Energy-Splitting-in-Dimer Method 936 3.1.2. The Orthogonality Issue 937 3.1.3. Impact of the Site Energy 937 3.1.4. Electronic Coupling in Oligoacene Derivatives 938

Charge transport in organic semiconductors.

Direct printing of functional electronic materials may provide a new route to low-cost fabrication of integrated circuits. However, to be useful it must allow continuous manufacturing of all circuit components by successive solution deposition and printing steps in the same environment. We demonstrate direct inkjet printing of complete transistor circuits, including via-hole interconnections based on solution-processed polymer conductors, insulators, and self-organizing semiconductors. We show that the use of substrate surface energy patterning to direct the flow of water-based conducting polymer inkjet droplets enables high-resolution definition of practical channel lengths of 5 micrometers. High mobilities of 0.02 square centimeters per volt second and on-off current switching ratios of 10 5 were achieved.

/pdf/high-resolution-inkjet-printing-of-all-polymer-transistor-5gs8q70grx.pdf

High-Resolution Inkjet Printing of All-Polymer Transistor Circuits

An organic field effect transistor featuring the chiral molecule helicene acts as a photodetector that is able to distinguish between left- and right-handed circularly polarized light.

Circularly polarized light detection by a chiral organic semiconductor transistor

Current–voltage, impedance, and transient conductance measurements have been carried out on indium-tin-oxide/poly(phenylene vinylene)/Al light emitting diodes. In these devices injection and transport is expected to be dominated by positive carriers. Fowler–Nordheim tunneling theory cannot account for the temperature dependence, the thickness dependence, or the current magnitude of the current–voltage characteristics. Space-charge limited current theory with an exponential distribution of traps is however in extremely good agreement with all of the recorded current–voltage results in the higher applied bias regime (approximately 0.7⩽V/d⩽1.6×106 V cm−1). This gives a trap density Ht of 5(±2)×1017 cm−3 and the product of μNHOMO of between 1014 and 5×1012 cm−1 V−1 s−1. Assuming NHOMO is 1020 cm−3 gives an effective positive carrier mobility between 10−6 and 5×10−8 cm2 V−1 s−1. The characteristic energy Et of the exponential trap distribution is 0.15 eV at higher temperatures (190⩽T⩽290 K), but this decreases...

Space-charge limited conduction with traps in poly(phenylene vinylene) light emitting diodes

The origin of electrophosphorescence from a doped polymer light emitting diode (LED) has been investigated. A luminescent polymer host, poly(9,9-dioctylfluorene) (PFO), was doped with a red phosphorescent dye, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (PtOEP). The maximum external quantum efficiency of 3.5% was obtained at a concentration of 4% PtOEP by weight. Energy transfer mechanisms between PFO and PtOEP were studied by absorption, photoluminescence, and photoinduced absorption spectroscopy. Even though electroluminescence spectra were dominated by PtOEP at a concentration of only 0.2 wt% PtOEP, Forster transfer of singlet excitons was weak and there was no evidence for Dexter transfer of triplet excitons. We conclude that the dominant emission mechanism in doped LED{close_quote}s is charge trapping followed by recombination on PtOEP molecules.

/pdf/origin-of-electrophosphorescence-from-a-doped-polymer-light-4tiutgpbgz.pdf

Origin of electrophosphorescence from a doped polymer light emitting diode

Here, we report results of both traditional current mode and current integration mode time-of-flight (TOF) measurements on the electroluminescent polyfluorene copolymer poly(9,9-dioctylfluorene-co-benzothiadiazole) (BT). Current mode TOF shows a strong but dispersive electron transport signal. The mobility derived from the current integration mode transit time (tQ) increases with decreasing film thickness as expected for dispersive transport. The fastest carriers in the photogenerated carrier packet are estimated to have mobilities of order 10−3 cm2/V s at applied fields of 0.5 MV/cm. Holes are heavily trapped close to the interface at which they are photogenerated. The TOF signals decay with repeated measurement and tQ remains constant with applied field. The transport properties of BT are thus in complete contrast to those of other polyfluorenes which show high-mobility nondispersive hole transport but weak and highly dispersive electron transport.

Dispersive electron transport in an electroluminescent polyfluorene copolymer measured by the current integration time-of-flight method

Detailed studies of hole mobility in the electroluminescent conjugated polymer poly($9,{9}^{\ensuremath{'}}$-dioctylfluorene) by the time-of-flight technique are reported. The hole mobility is studied in a number of samples over a wide range of temperatures and electric field strengths. Significant sample-to-sample variations are observed in both hole mobility and the character of hole transport in as-spun films of different thicknesses. Hole mobility is found to improve irreversibly as a result of thermal annealing at elevated temperatures. Analysis of the experimental results is carried out within the Gaussian disorder model (GDM), the polaronic correlated disorder model (PCDM), and the geometry fluctuation model based on torsional interactions (known here as the Los Alamos model). The PCDM is found to be more successful than the GDM in explaining the experimental data. Moreover, the Los Alamos model succeeds in explaining the data when modified to include polaron hopping. Analysis with both PCDM and Los Alamos models leads to the conclusion that the improvement in hole mobility upon annealing is consistent with reduced energetic disorder and reduced polaron binding energy, both of which may result from crystallization of the material. Spectroscopic ellipsometry is used to confirm that crystallization occurs upon annealing.

Alasdair J. Campbell

Papers

Circularly polarized light detection by a chiral organic semiconductor transistor

Space-charge limited conduction with traps in poly(phenylene vinylene) light emitting diodes

Origin of electrophosphorescence from a doped polymer light emitting diode

Dispersive electron transport in an electroluminescent polyfluorene copolymer measured by the current integration time-of-flight method

Temperature and field dependence of hole mobility in poly(9,9-dioctylfluorene)