Search results for " mobility"
showing 10 items of 577 documents
Space Charge and Carrier Trapping Effects on the Transient Photocurrents of Organic Materials Using the Time-of-Flight Technique
2007
We apply the time-of-flight (TOF) technique to study space charge and carrier trapping effects in the organic materials N,N'-diphenyl-N,N'-bis(3- methylphenyl)-1,1-biphenyl-4,4'-diamine (TPD) and tris(8-hydroxyquinolato) aluminum (Alq3). This is carried out by changing the applied electric field, the laser pulse intensity, and the repetition rate together with environmental conditions in air or in vacuum. We report for the first time, to the best of our knowledge, a clearly nondispersive electron transport in TPD due to the absence of deep traps. Conversely, Alq3 exhibits a dispersive electron transport. However, this can be partially recovered by leaving the sample in high vacuum for sever…
SURFACE EFFECTS ON THE GROWTH OF SOLUTION PROCESSED PENTACENE THIN FILMS
2008
13,6-N-Sulfinylacetamidopentacene (SAP) has been transferred on solid substrates both by water-rich environment and organic solvents without altering his chemical structure. Thermal conversion of SAP to pentacene leads to crystals showing similar features of vacuum-sublimated pentacene both in the bulk and thin-film phases. The thin-film phase is strongly affected by the substrate surface properties. Low energy Si-CH3 rich surfaces allow for the formation of compact micrometric crystals following a Volmer-Weber like growth with orientation suitable for field-effect carrier mobility. Screw dislocations along with straight edges are found on these systems as an indication of a loose interlaye…
Differently substituted benzonitriles for non-doped OLEDs
2020
DG acknowledges to the ERDF PostDoc grant No. 1.1.1.2/VIAA/1/16/177 . This research was funded by the European Regional Development Fund according to the supported activity ‘Research Projects Implemented by World-class Researcher Groups’ under Measure No. 01.2.2-LMT-K-718 .
Discotic Liquid Crystals - A New Class of Fast Photoconductors
1993
We showed for the first time that discotic liquid crystals are well suited for a new class of fast photoconducting materials. Due to their spontaneous orientation and their dynamical fluctuations in the mesophase, they show exceptionally high mobilities of 1·10−3 cm2/Vs, about two to three orders of magnitude higher than those obtained for conventional amorphous polymers. Further on, the Gaussian transport (for holes in the mesophase) is remarkable, which is characterized by the existence of a conduction band and the absence of trapping states. In contrast, the charge carrier transport in amorphous photoconductors is generally trap-dominated which limits technical properties, leading to low…
High-pressure electrical transport measurements on p-type GaSe and InSe
2006
We performed high-pressure Hall effect and resistivity measurements in p-type GaSe and InSe up to 12 GPa. The pressure behaviour of the transport parameters shows dramatic differences between both materials. In GaSe, the hole concentration and mobility increase moderately and continuously. In InSe, the hole mobility raises rapidly and the hole concentration increases abruptly near 0.8 GPa. The observed results are attributed to the different pressure evolution of the valence-band structure in each material. In InSe a carrier-type inversion is also detected near 4.5 GPa.
Overexpression of the truncated form of high mobility group a proteins (HMGA2) in human myometrial cells induces leiomyoma-like tissue formation
2014
The pathogenesis of uterine leiomyomas, the most common benign tumor in women, is still unknown. This lack of basic knowledge limits the development of novel non-invasive therapies. Our group has previously demonstrated that leiomyoma side population (SP) cells are present in tumor lesions and act like putative tumor-initiating stemcells in human leiomyoma. Moreover, accumulated evidence demonstrates that these benign tumors of mesenchymal origin are characterized by rearrangements of the High Mobility Group A proteins (HMGA). In this work, we tested the hypothesis that leiomyoma development may be due to overexpression of HMGA2 (encoding high mobility group AT-hook2) in myometrial stem cel…
Graphical models for estimating network determinants of multi-destination trips in Sicily
2017
Abstract This paper proposes a two-step approach for analysing the main determinants of multi-destination trip behaviour. It is based on a combination of graphical models and of a multinomial logistic regression model; the aim is to analyse direct and indirect effects of a wide set of tourist- and trip-related characteristics on multi-destination trip behaviour. Empirical data have been derived from a frontier survey of approximately 4000 incoming tourists in Sicily (Italy) at the end of their trip. Results suggest that multi-destination trips depend directly on the length of stay, the number of previous visits and motivation for the trip, and only indirectly on the interview month, travel …
T helper 17 lineage differentiation is programmed by orphan nuclear receptors ROR alpha and ROR gamma.
2007
T cell functional differentiation is mediated by lineage-specific transcription factors. T helper 17 (Th17) has been recently identified as a distinct Th lineage mediating tissue inflammation. Retinoic acid receptor-related orphan receptor gamma (ROR gamma) was shown to regulate Th17 differentiation; ROR gamma deficiency, however, did not completely abolish Th17 cytokine expression. Here, we report Th17 cells highly expressed another related nuclear receptor, ROR alpha, induced by transforming growth factor-beta and interleukin-6 (IL-6), which is dependent on signal transducer and activator of transcription 3. Overexpression of ROR alpha promoted Th17 differentiation, possibly through the c…
Energy Saving in Public Transport Using Renewable Energy
2017
Hydrogen produced by renewable sources represents an interesting way to reduce the energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study for the production, storage and distribution of hydrogen in the western Sicilian context, using three different renewable sources: wind, biomass and sea wave. The objective of this study is the evaluation of the hydrogen demand, needed to replace all diesel supplied buses with electrical buses equipped with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the renewable en…
Hydrogen Production from Sea Wave for Alternative Energy Vehicles for Public Transport in Trapani (Italy)
2016
The coupling of renewable energy and hydrogen technologies represents in the mid-term a very interesting way to match the tasks of increasing the reliable exploitation of wind and sea wave energy and introducing clean technologies in the transportation sector. This paper presents two different feasibility studies: the first proposes two plants based on wind and sea wave resource for the production, storage and distribution of hydrogen for public transportation facilities in the West Sicily; the second applies the same approach to Pantelleria (a smaller island), including also some indications about solar resource. In both cases, all buses will be equipped with fuel-cells. A first economic a…