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排序方式: 共有620条查询结果,搜索用时 62 毫秒
71.
Maximilian Moser Tania Cecilia Hidalgo Jokubas Surgailis Johannes Gladisch Sarbani Ghosh Rajendar Sheelamanthula Quentin Thiburce Alexander Giovannitti Alberto Salleo Nicola Gasparini Andrew Wadsworth Igor Zozoulenko Magnus Berggren Eleni Stavrinidou Sahika Inal Iain McCulloch 《Advanced materials (Deerfield Beach, Fla.)》2020,32(37):2002748
A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [μC*] and current retentions up to 98% over 700 electrochemical switching cycles are developed. 相似文献
72.
Alexandra F. Paterson Hendrik Faber Achilleas Savva Georgios Nikiforidis Murali Gedda Tania C. Hidalgo Xingxing Chen Iain McCulloch Thomas D. Anthopoulos Sahika Inal 《Advanced materials (Deerfield Beach, Fla.)》2019,31(37)
Contact resistance is renowned for its unfavorable impact on transistor performance. Despite its notoriety, the nature of contact resistance in organic electrochemical transistors (OECTs) remains unclear. Here, by investigating the role of contact resistance in n‐type OECTs, the first demonstration of source/drain‐electrode surface modification for achieving state‐of‐the‐art n‐type OECTs is reported. Specifically, thiol‐based self‐assembled monolayers (SAMs), 4‐methylbenzenethiol (MBT) and pentafluorobenzenethiol (PFBT), are used to investigate contact resistance in n‐type accumulation‐mode OECTs made from the hydrophilic copolymer P‐90, where the deliberate functionalization of the gold source/drain electrodes decreases and increases the energetic mismatch at the electrode/semiconductor interface, respectively. Although MBT treatment is found to increase the transconductance three‐fold, contact resistance is not found to be the dominant factor governing OECT performance. Additional morphology and surface energy investigations show that increased performance comes from SAM‐enhanced source/drain electrode surface energy, which improves wetting, semiconductor/metal interface quality, and semiconductor morphology at the electrode and channel. Overall, contact resistance in n‐type OECTs is investigated, whilst identifying source/drain electrode treatment as a useful device engineering strategy for achieving state of the art n‐type OECTs. 相似文献
73.
By applying the Linguistic Category Model (LCM) in crisis communication, this study explores the potential of verb tracking on social media to examine how linguistic categories can elucidate the intentional and/or unintentional communication of crisis attribution frames. Through a content analysis, linguistic categories used in both media posts reporting three clusters of crisis and public comments on Facebook were examined. Results indicated that linguistic abstraction in both media post and public comments describing the crisis varied based on crisis cluster, suggesting that the level of linguistic abstraction reflected perceived attribution of responsibility through stability, locus and controllability. Language used to describe preventable crisis tend to be more abstract than those used to describe accidental and victim crisis. Findings of this study empirically tested the integration of LCM in crisis communication and implied potential application of LCM in building automated environmental scanning and crisis prediction systems. 相似文献
74.
Mingfei Xiao Aditya Sadhanala Mojtaba Abdi-Jalebi Tudor H. Thomas Xinglong Ren Tao Zhang Hu Chen Remington L. Carey Qijing Wang Satyaprasad P. Senanayak Cameron Jellett Ada Onwubiko Maximilian Moser Hailiang Liao Wan Yue Iain McCulloch Mark Nikolka Henning Sirringhaus 《Advanced functional materials》2021,31(7):2007359
The measurement of the mechanical properties of conjugated polymers can reveal highly relevant information linking optoelectronic properties to underlying microstructures and the knowledge of the glass transition temperature (Tg) is paramount for informing the choice of processing conditions and for interpreting the thermal stability of devices. In this work, we use dynamical mechanical analysis to determine the Tg of a range of state-of-the-art conjugated polymers with different degrees of crystallinity that are widely studied for applications in organic field-effect transistors. We compare our measured values for Tg to the theoretical value predicted by a recent work based on the concept of effective mobility ζ. The comparison shows that for conjugated polymers with a modest length of the monomer units, the Tg values agree well with theoretically predictions. However, for the near-amorphous, indacenodithiophene–benzothiadiazole family of polymers with more extended backbone units, values for Tg appear to be significantly higher, predicted by theory. However, values for Tg are correlated with the sub-bandgap optical absorption suggesting the possible role of the interchain short contacts within materials’ amorphous domains. 相似文献
75.
Iuliana P. Maria Bryan D. Paulsen Achilleas Savva David Ohayon Ruiheng Wu Rawad Hallani Aniruddha Basu Weiyuan Du Thomas D. Anthopoulos Sahika Inal Jonathan Rivnay Iain McCulloch Alexander Giovannitti 《Advanced functional materials》2021,31(14):2008718
Conjugated polymers with mixed ionic and electronic transport are essential for developing the complexity and function of electrochemical devices. Current n-type materials have a narrow scope and low performance compared with their p-type counterparts, requiring new molecular design strategies. This work presents two naphthalene diimide-bithiophene (NDI-T2) copolymers functionalized with hybrid alkyl-glycol side chains, where the naphthalene diimide unit is segregated from the ethylene glycol (EG) units within the side chain by an alkyl spacer. Introduction of hydrophobic propyl and hexyl spacers is investigated as a strategy to minimize detrimental swelling close to the conjugated backbone and balance the mixed conduction properties of n-type materials in aqueous electrolytes. It is found that both polymers functionalized with alkyl spacers outperform their analogue bearing EG-only side chains in organic electrochemical transistors (OECTs). The presence of the alkyl spacers also leads to remarkable stability in OECTs, with no decrease in the ON current after 2 h of operation. Through this versatile side chain modification, this work provides a greater understanding of the structure-property relationships required for n-type OECT materials operating in aqueous media. 相似文献
76.
Siew Ting Melissa Tan Alexander Giovannitti Armantas Melianas Maximilian Moser Benjamin L. Cotts Devan Singh Iain McCulloch Alberto Salleo 《Advanced functional materials》2021,31(19):2010868
Organic electrochemical transistors (OECTs) have exhibited promising performance as transducers and amplifiers of low potentials due to their exceptional transconductance, enabled by the volumetric charging of organic mixed ionic/electronic conductors (OMIECs) employed as the channel material. OECT performance in aqueous electrolytes as well as the OMIECs’ redox activity has spurred a myriad of studies employing OECTs as chemical transducers. However, the OECT's large (potentiometrically derived) transconductance is not fully leveraged in common approaches that directly conduct chemical reactions amperometrically within the OECT electrolyte with direct charge transfer between the analyte and the OMIEC, which results in sub-unity transduction of gate to drain current. Hence, amperometric OECTs do not truly display current gains in the traditional sense, falling short of the expected transistor performance. This study demonstrates an alternative device architecture that separates chemical transduction and amplification processes on two different electrochemical cells. This approach fully utilizes the OECT's large transconductance to achieve current gains of 103 and current modulations of four orders of magnitude. This transduction mechanism represents a general approach enabling high-gain chemical OECT transducers. 相似文献
77.
J. W. Wong V. Verigin A. C. Oehlschlager J. H. Borden H. D. Pierce Jr. A. M. Pierce L. Chong 《Journal of chemical ecology》1983,9(4):451-474
Two synergistic macrolide aggregation pheromones were isolated from Porapak Q-trapped volatiles obtained from the frass ofCryptolestes ferrugineus (Stephens). These compounds were identified as (E,E)-4,8-dimethyl-4,8-decadien-10-olide (I) and (3Z,11S)-3-dodecen-11-olide (II) and given the trivial names ferrulactone I and II, respectively. Analysis of captured volatiles from separated male and female adults disclosed that the pheromones are male-produced. Additional macrolides were identified in frass volatiles, but were devoid of any pheromonal activity. The structures of I and II were confirmed by comparison with synthetic materials. 相似文献
78.
P. D. C. Wimalaratne K. N. Slessor J. H. Borden L. J. Chong T. Abate 《Journal of chemical ecology》1996,22(1):49-59
Foliage from the pepper tree,Schinus molle L., is traditionally used in Ethiopia to repel house flies,Musca domestica L. The volatile extracts of pepper tree leaves were shown to have repellent and feeding-deterrent activity against house flies in a two-choice laboratory bioassay. High-performance liquid chromatographic fractionation of steam-distilled volatiles from leaves, monitored by laboratory bioassays, demonstrated that bioactivity is associated with two compounds,cis-menth-2-en-1-ol andtrans-piperitol. The absolute configuration of the latter was established as (1S,6S)-piperitol by comparison of acetyl lactate derivatives. Racemic compounds were synthesized from piperitone, and bioassays with house flies indicatedtrans-piperitol to be the most active house fly repellent. 相似文献
79.
R. S. Vernon J. H. Borden H. D. Pierce Jr. A. C. Oehlschlager 《Journal of chemical ecology》1977,3(4):359-368
An oviposition bioassay for the onion maggot,Hylemya antiqua (Meigen), is described in which females, in response to volatile stimulants, oviposit through small apertures onto moistened filter paper. Onion volatiles that act as attractants and oviposition stimulants were captured in Porapak Q from air passed over chopped onions in glass chambers. Pentane extracts from odor-impregnated Porapak Q induced 30–50% of the oviposition that occurred in response to 15-g onion-slice stimuli. Extracts presented in pentane on waxed dental cotton wicks induced more constant oviposition over a 3-day period than extracts on unwaxed wicks. Extract of the Porapak Q-captured volatiles from bulbs of fresh, actively growing onions elicited a much stronger response than did stem and leaf extracts from the same onions. The bioassay techniques and chemical procedures developed in this study could be used in chemical isolation programs for host attractants or oviposition stimulants forH. antiqua or similar species.Diptera:Anthomyiidae.Research supported by National Research Council of Canada, Grant Nos. A3881 and A3706. 相似文献
80.
Iain Jackson 《The Journal of Architecture》2016,21(3):375-417
This paper seeks to examine and contextualise the architecture and infrastructure projects developed by the British during the occupation of Iraq in the First World War and the Mandate period that immediately followed. Relying heavily on military-political events for its structure and underlying narrative, the paper demonstrates how architecture, planning and ‘development’ were integral to the act of creating the new state and were very much part of the colonisers’ vision to create a nation in their own image. Works were deployed to imbue a sense of collective belonging and national identity through the creation of new town plans, as well as through institutions such as museums and universities. A certain dissonance emerges between the infrastructure and prestige projects, with the latter presenting an imagined and fabricated notion of Iraqi history, blended with a grandiose colonial style imported from India, and designed predominantly by James M. Wilson. The infrastructure projects began with sanitation improvements, road and rail installation, and expansion of the Basra docklands to attract international shipping and for the export of oil. Further building projects undertaken by the Public Works Department included a large number of administrative buildings called serais. Built at strategic locations, they were deployed as multi-functional centres for justice, taxation and land registration as well as places where local devolved empowerment was instigated. Iraqi architecture from this period has been largely overlooked in the emerging global histories of architecture, yet it offers an important view of the quandaries that faced late British colonial architecture in its attempts to respond to, and reflect changing and hostile political conditions. 相似文献