A fluorenone based low band gap solution processable copolymer for air stable and high mobility organic field effect transistors

A fluorenone based alternating copolymer (PFN-DPPF) with a furan based fused aromatic moiety has been designed and synthesized. PFN-DPPF exhibits a small band gap with a lower HOMO value. Testing this polymer semiconductor as the active layer in organic thin-film transistors results in hole mobilities as high as 0.15 cm2 V-1 s-1 in air.

High mobility organic thin film transistor and efficient photovoltaic devices using versatile donor-acceptor polymer semiconductor by molecular design

In this work, we report a novel donor-acceptor based solution processable low band gap polymer semiconductor, PDPP-TNT, synthesized via Suzuki coupling using condensed diketopyrrolopyrrole (DPP) as an acceptor moiety with a fused naphthalene donor building block in the polymer backbone. This polymer exhibits p-channel charge transport characteristics when used as the active semiconductor in organic thin-film transistor (OTFT) devices. The hole mobilities of 0.65 cm2 V-1 s-1 and 0.98 cm2 V -1 s-1 are achieved respectively in bottom gate and dual gate OTFT devices with on/off ratios in the range of 105 to 10 7. Additionally, due to its appropriate HOMO (5.29 eV) energy level and optimum optical band gap (1.50 eV), PDPP-TNT is a promising candidate for organic photovoltaic (OPV) applications. When this polymer semiconductor is used as a donor and PC71BM as an acceptor in OPV devices, high power conversion efficiencies (PCE) of 4.7% are obtained. Such high mobility values in OTFTs and high PCE in OPV make PDPP-TNT a very promising polymer semiconductor for a wide range of applications in organic electronics.

A low-bandgap diketopyrrolopyrrole-benzothiadiazole-based copolymer for high-mobility ambipolar organic thin-film transistors

A new, solution-processable, low-bandgap, diketopyrrolopyrrole- benzothiadiazole-based, donor-acceptor polymer semiconductor (PDPP-TBT) is reported. This polymer exhibits ambipolar charge transport when used as a single component active semiconductor in OTFTs with balanced hole and electron mobilities of 0.35 cm2 V-1s-1 and 0.40 cm 2 V-1s-1, respectively. This polymer has the potential for ambipolar transistor-based complementary circuits in printed electronics.

High-mobility organic thin film transistors based on benzothiadiazole- sandwiched dihexylquaterthiophenes

We report here the synthesis, characterization, and organic thin-film transistor (OTFT) mobilities of 4,7-bis(5-(5-hexylthiophen-2-yl)thiophen-2-yl) benzo[1,2,5]thiadiazole (DH-BTZ-4T). DH-BTZ-4T was prepared in one high-yield step from commercially available materials using Suzuki chemistry and purified by column chromatography. OTFTs with hole mobilities of 0.17 cm2/(Vs) and on/off current ratios of 1 × 105 were prepared from DH-BTZ-4T active layers deposited by vacuum deposition. As DH-BTZ-4T is soluble in common solvents, solution processed devices were also prepared by spin coating yielding preliminary mobilities of 6.0 × 10-3 cm 2/(Vs). The promising mobilities and low band gap (1.90 eV) coupled with solution processability and ambient stability makes this material an excellent candidate for application in organic electronics.

Furan substituted diketopyrrolopyrrole and thienylenevinylene based low band gap copolymer for high mobility organic thin film transistors

A novel solution processable donor-acceptor (D-A) based low band gap polymer semiconductor poly{3,6-difuran-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4- c]pyrrole-1,4-dione-alt-thienylenevinylene} (PDPPF-TVT), was designed and synthesized by a Pd-catalyzed Stille coupling route. An electron deficient furan based diketopyrrolopyrrole (DPP) block and electron rich thienylenevinylene (TVT) donor moiety were attached alternately in the polymer backbone. The polymer exhibited good solubility, film forming ability and thermal stability. The polymer exhibits wide absorption bands from 400 nm to 950 nm (UV-vis-NIR region) with absorption maximum centered at 782 nm in thin film. The optical band gap (Eoptg) calculated from the polymer film absorption onset is around 1.37 eV. The π-energy band level (ionization potential) calculated by photoelectron spectroscopy in air (PESA) for PDPPF-TVT is around 5.22 eV. AFM and TEM analyses of the polymer reveal nodular terrace morphology with optimized crystallinity after 200 °C thermal annealing. This polymer exhibits p-channel charge transport characteristics when used as the active semiconductor in organic thin-film transistor (OTFT) devices. The highest hole mobility of 0.13 cm 2 V -1 s -1 is achieved in bottom gate and top-contact OTFT devices with on/off ratios in the range of 10 6-10 7. This work reveals that the replacement of thiophene by furan in DPP copolymers exhibits such a high mobility, which makes DPP furan a promising block for making a wide range of promising polymer semiconductors for broad applications in organic electronics.

Relation between charge carrier mobility and lifetime in organic photovoltaics

The relationship between charge carrier lifetime and mobility in a bulk heterojunction based organic solar cell, utilizing diketopyrrolopyrole- naphthalene co-polymer and PC71BM in the photoactive blend layer, is investigated using the photoinduced charge extraction by linearly increasing voltage technique. Light intensity, delay time, and temperature dependent experiments are used to quantify the charge carrier mobility and density as well as the temperature dependence of both. From the saturation of photoinduced current at high laser intensities, it is shown that Langevin-type bimolecular recombination is present in the studied system. The charge carrier lifetime, especially in Langevin systems, is discussed to be an ambiguous and unreliable parameter to determine the performance of organic solar cells, because of the dependence of charge carrier lifetime on charge carrier density, mobility, and type of recombination. It is revealed that the relation between charge mobility (μ) and lifetime (τ) is inversely proportional, where the μτ product is independent of temperature. The results indicate that in photovoltaic systems with Langevin type bimolecular recombination, the strategies to increase the charge lifetime might not be beneficial because of an accompanying reduction in charge carrier mobility. Instead, the focus on non-Langevin mechanisms of recombination is crucial, because this allows an increase in the charge extraction rate by improving the carrier lifetime, density, and mobility simultaneously. © 2013 AIP Publishing LLC.

Correlates of perceiving human resource management as a 'problem' in smaller firms

In this paper we investigate factors likely to correlate with human resource management (HRM) being perceived as a problem in smaller firms. The owner-manager and firm characteristics identified recognise that managerial ‘problems’ can result from a firm’s phase of growth, as well as the way in which an owner-manager’s capacity and characteristics affect their interpretation of such. From a survey of 1200 smaller firms in south east Melbourne (Australia), we use logistic regression on data from 428 respondents to assess organisational and individual factors correlating with perceiving HRM, broadly defined, to be a problem. The highest odds of this occurring were associated with being a larger manufacturing firm which was in a phase of growth other than diversification and which had a long-tenured manager who based the firm’s competitive success on factors other than the quality of staff. Knowing these correlates means assistance to help solve the perceived ‘problem’ with HRM can be more effectively targeted.

Introduction : At the Intersection of Entrepreneurship and Human Resource Management

In recent years there has been a growing literature on human resource management (HRM) and smaller firms which has also encompassed firms that are growing and entrepreneurial. For example we have seen a special edition of Entrepreneurship Theory and Practice (Katz et al., 2000), two of Human Resource Management Review (Baron, 2003; Barrett and Mayson, 2006) and one of Human Resource Management (Huselid, 2003; Tansky and Heneman, 2003), with another of Human Resource Management (to be edited by Ribeiro, Roig and Tansky) scheduled for publication in 2010. In addition, symposia on the topic have been undertaken at the Academy of Management in 2005 (organized by Mayson) and in 2004 (organized by Hayton). Papers dealing with issues of HRM for new, small, growing and/or entrepreneurial firms have been presented at a range of different conferences, whether they are management oriented such as the Academy of Management (AoM) and its regional variants (for example, the British Academy of Management (BAM) or the Australian and New Zealand Academy of Management (ANZAM)), entrepreneurially focused ones like the Babson College Entrepreneurship Research conference or ones focused specifically on smaller firms such as the conferences of the Institute for Small Business and Entrepreneurship (ISBE) in the UK or the International Council for Small Business (ICSB) and its regional affiliates. With all these papers and all this discussion is there anything left to say? Well yes, we think there is and we are...

Human resource management and entrepreneurship : building theory at the intersection

In 2008 we brought together much work at the intersection of entrepreneurship and human resource management (HRM) (Barrett & Mayson, 2008), after calls for more research (Baron, 2003; Katz, Aldrich, Welbourne & Williams, 2000; Tansky & Heneman, 2003). More has been collated since (Soriano, Dobon & Tansky, 2010; Tansky, Soriano & Dobon, 2010). We think it is now time again to regroup, pull conversational threads together and have a critical look at recent research at the intersection of HRM and Entrepreneurship. As editors of International Handbook of Entrepreneurship and HRM (Barrett & Mayson, 2008) we were privileged to collect 23 wonderfully diverse chapters from scholars around the globe addressing a range of issues at the intersection of the two pertinent disciplines or fields: HRM and entrepreneurship. This edition represented a coalescing of ideas that had been swirling about for some time. In three sections, the first dealt with theory and research methods, the second with the nature of HRM in small and entrepreneurial firms and the third with the functional aspects of HRM. At the time we were aware that the handbook did not cover the entire field and many topics were left unexplored. For example, the topic of regulation was generally absent while issues such as career advancement, performance management, organisational change and gender, diversity and ethnicity were also missing. In essence, the majority of those contributions sought to develop an understanding of the context in which particular aspects of HRM can be played out.

Non-invasive techniques for imaging in-vivo human corneal sub basal nerve mapping and migration rate in diabetic neuropathy

Purpose Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic technique, which has been shown to diagnose and stratify the severity of diabetic neuropathy. Current morphometric techniques assess individual static images of the subbasal nerve plexus; this work explores the potential for non-invasive assessment of the wide-field morphology and dynamic changes of this plexus in vivo. Methods In this pilot study, laser scanning CCM was used to acquire maps (using a dynamic fixation target and semi-automated tiling software) of the central corneal sub-basal nerve plexus in 4 diabetic patients with and 6 without neuropathy and in 2 control subjects. Nerve migration was measured in an additional 7 diabetic patients with neuropathy, 4 without neuropathy and in 2 control subjects by repeating a modified version of the mapping procedure within 2-8 weeks, thus facilitating re-identification of distinctive nerve landmarks in the 2 montages. The rate of nerve movement was determined from these data and normalised to a weekly rate (µm/week), using customised software. Results Wide-field corneal nerve fibre length correlated significantly with the Neuropathy Disability Score (r = -0.58, p < 0.05), vibration perception (r = -0.66, p < 0.05) and peroneal conduction velocity (r = 0.67, p < 0.05). Central corneal nerve fibre length did not correlate with any of these measures of neuropathy (p > 0.05 for all). The rate of corneal nerve migration was 14.3 ± 1.1 µm/week in diabetic patients with neuropathy, 19.7 ± 13.3µm/week in diabetic patients without neuropathy, and 24.4 ± 9.8µm/week in control subjects; however, these differences were not significantly different (p = 0.543). Conclusions Our data demonstrate that it is possible to capture wide-field images of the corneal nerve plexus, and to quantify the rate of corneal nerve migration by repeating this procedure over a number of weeks. Further studies on larger sample sizes are required to determine the utility of this approach for the diagnosis and monitoring of diabetic neuropathy.

Mobility in the child (and carer) friendly city : SEQ vs. Stockholm

The rationale for providing state subsidised public transport has changed over time from a social obligation to provide transport options for those without access to private transport to an environmental and economic imperative to minimize congestion and greenhouse gas emissions. In many jurisdictions this shift has seen a greater focus on the provision of peak hour commuter services and a shift in the demographic profile of the riding public and a significant increase in the number of commuter passengers relative to others. The scheduling of commuter services is not geared to meet the needs of children and their generally female carers who often need to engage in trip chaining and travel outside peak commuting periods and on weekends. In addition to service scheduling difficulties, transport infrastructure, both on-board and supporting infrastructure such as bus stops, train stations and connecting footpaths often do not support children and their carers to use public transport services. Combined with a negative attitude by passengers and service providers, such as bus drivers, which may see children, babies and young people as out of place and unwelcome on commuter services, these issues conspire to hinder the use of public transport by children and their carers. Overlaying feminist geography analysis and insights and child-friendly cities objectives, this paper proposes some basic criteria for the provision of public transport services and supporting infrastructure which meets the needs of children, babies and their carers and juxtaposes the achievement of these in South East Queensland, Australia and Stockholm, Sweden.

Human CD141(+) (BDCA-3)(+) dendritic cells (DCs) represent a unique myeloid DC subset that cross-presents necrotic cell antigens

The characterization of human dendritic cell (DC) subsets is essential for the design of new vaccines. We report the first detailed functional analysis of the human CD141(+) DC subset. CD141(+) DCs are found in human lymph nodes, bone marrow, tonsil, and blood, and the latter proved to be the best source of highly purified cells for functional analysis. They are characterized by high expression of toll-like receptor 3, production of IL-12p70 and IFN-beta, and superior capacity to induce T helper 1 cell responses, when compared with the more commonly studied CD1c(+) DC subset. Polyinosine-polycytidylic acid (poly I:C)-activated CD141(+) DCs have a superior capacity to cross-present soluble protein antigen (Ag) to CD8(+) cytotoxic T lymphocytes than poly I:C-activated CD1c(+) DCs. Importantly, CD141(+) DCs, but not CD1c(+) DCs, were endowed with the capacity to cross-present viral Ag after their uptake of necrotic virus-infected cells. These findings establish the CD141(+) DC subset as an important functionally distinct human DC subtype with characteristics similar to those of the mouse CD8 alpha(+) DC subset. The data demonstrate a role for CD141(+) DCs in the induction of cytotoxic T lymphocyte responses and suggest that they may be the most relevant targets for vaccination against cancers, viruses, and other pathogens.

Profiling human resource management practices in innovative firms

It has been argued that different bundles or configurations of human resource practices can improve innovation performance, but there is little empirically-based research that provides details of the practices utilised by different types of innovative firms. This study aimed to identify how different types of firms vary their HR practices to build organisation-specific innovation capabilities. The paper presents findings from a qualitative study of 26 innovative Danish firms categorised as technology-based, knowledge-intensive, or hybrid in their industry orientation. The findings highlight that knowledge-intensive firms have notably different profiles of HRM practices to technology-based firms, suggesting that firms utilise different practices to build innovation capacity depending on the core capabilities required for success in their respective industries. This paper contributes by demonstrating how HR practices differ across types of firms rather than relying on a universal perspective or one best way to design and implement HR practices.

Assessment of Geogenic Contaminants in Water Co-Produced with Coal Seam Gas Extraction in Queensland, Australia : Implications for Human Health Risk

Organic compounds in Australian coal seam gas produced water (CSG water) are poorly understood despite their environmental contamination potential. In this study, the presence of some organic substances is identified from government-held CSG water-quality data from the Bowen and Surat Basins, Queensland. These records revealed the presence of polycyclic aromatic hydrocarbons (PAHs) in 27% of samples of CSG water from the Walloon Coal Measures at concentrations <1 µg/L, and it is likely these compounds leached from in situ coals. PAHs identified from wells include naphthalene, phenanthrene, chrysene and dibenz[a,h]anthracene. In addition, the likelihood of coal-derived organic compounds leaching to groundwater is assessed by undertaking toxicity leaching experiments using coal rank and water chemistry as variables. These tests suggest higher molecular weight PAHs (including benzo[a]pyrene) leach from higher rank coals, whereas lower molecular weight PAHs leach at greater concentrations from lower rank coal. Some of the identified organic compounds have carcinogenic or health risk potential, but they are unlikely to be acutely toxic at the observed concentrations which are almost negligible (largely due to the hydrophobicity of such compounds). Hence, this study will be useful to practitioners assessing CSG water related environmental and health risk.

The Journey of Becoming Involved in Urban Spaces by Children with Diverse Mobility

Participation is a word frequently espoused in the literature of childhood and urban studies. It has also been made sacrosanct through the Convention on the Rights of the Child and other rights-based policy and programming. Despite this importance, what it means and how it is experienced in the everyday lives of children with diverse abilities is not well understood. This chapter provides insight into the everyday experiences of participation by ten children 9-12 years of age, who have diverse personal mobility from various physical conditions that affect muscle and movement differently, including: Muscular Dystrophy, Cerebral Palsy, and Autoimmune Rheumatic Diseases. The children participants live in the outer suburbs and inner regions of south-east Queensland, Australia. The chapter discusses a new way of understanding and theorising participation as a journey of becoming involved. This knowledge emerged through the children’s body-space-time routines (body ballets) and their descriptions of inhabiting urban space. This chapter also establishes how body-space-context interplays shape the experiences of becoming and being involved in everyday life, as well as the preconceptions of body embed in space which divide and constrain children and families actualisation of full and genuine participation.