Development of electrochromic thin-film transistors on flexible substrate

This work documents the fabrication and characterization of electrochromic thin-film transistors (ECTFTs) based on tungsten oxide (WO3). The ECTFTs exhibit double functionality (optical and electrical modulation) and were deposited on Corning glass and polyethylene naphthalate (PEN) by radio-frequency (RF) magnetron sputtering in an argon-oxygen atmospherewith no intentional substrate heating. The resulting amorphous WO3film connects source and drain in a planar configuration with three different architectures(conventional, interdigital and back-electrode) and isgated by a drop-casted lithium-based polymer electrolyte (LiClO4:PC). EC films were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM)andopto-electrochemical measurements, the electrolyte by electrochemicalimpedance spectroscopy (EIS) and the ECTFTs by static and dynamic electrical characterization. Thinner EC films (75 nm) evidenced lower optical density (ΔOD) and color efficiency (CE) of 0,26 and 21,85 cm2C-1, respectively, but faster EC reaction kinetics, with bleaching and coloration times (tband tc) of 1,8 and 3,8 seconds, respectively. In terms of electrical properties the best performing ECTFT architecture (interdigital) showed an ION/IOFFof 2,81x105and a transconductance of 2,24 mS. The back-electrode architecturehowever showed better ionic movement control in the channel(adjustable VON)with enhanced colorations, making ita better candidate for a two-in-one (pixel + transistor) solution for display applications

Cellulose Nanocrystal Chiral Structures for Electronics and Photonics

This dissertation reports on the integration of cellulose nanocrystals (CNCs) as photonic films into optoelectronic devices, where the films’ inherent left-handed mesoporous chiral nematic structure acts as a circular polarized light (CPL) filter in the visible light range. The outcome demonstrates for the first time micro- scopic semiconducting devices based on cellulose, capable of producing specific electronic outputs when irradiated with either left- or right- handed CPL (LCPL and RCPL, respectively). For this proof-of-concept two distinct optoelectronic devices are targeted: a thin-film field-effect transistor and a thin-film photodiode, spanning the whole visible electromagnetic spectrum. The devices are jointly developed each one with a specific type of CNC, presenting photonic bandgaps that are tuned for the active layer of the devices. On the one hand, lab-produced (home-made CNCs – HM-CNCs) are synthesized through sulfuric acid hydrol- ysis, yielding HM-CNC films with a photonic bandgap in the blue/UV region. On the other hand, industrially produced Na neutralized spray-dried CNCs by CelluForce (C-CNCs) are studied on behalf of their redispersion in water to yield C-CNC films with a photonic bandgap in the green/red region. The work is essentially divided into three main parts: • Study of liquid crystalline and photonic properties of HM-CNCs and C- CNCs in aqueous suspensions (Chapter 3) • Implementation of HM-CNCs into field-effect transistors (Chapter 5) • Implementation of C-CNCs into thin-film photodiodes (Chapter 6) The main objective of Chapter 5 deals with the implementation of HM-CNCs films, optimized through the first Objective in Chapter 3, into field-effect tran- sistors based on amorphous indium-gallium-zinc-oxide (a-IGZO) as the semicon- ductor. In the resulting devices the HM-CNC films take simultaneously the role of the devices’ dielectric as a solid-state electrolyte and as a photonic filter for CPL. Consequently, this study encompasses two sub-objectives, connected firstly to the study of the electrochemical properties of these films and their success- ful integration into field-effect transistors without compromising self-assembly behavior. And secondly, successful proof of CPL sensing capabilities of these devices. The final study shows the incorporation of C-CNC films, into amorphous silicon-based thin-film photodiodes, achieving a light sensor capable of discrimi- nating between RCPL and LCPL. The spectral response of the fabricated photo- diodes is maximum for specific wavelengths in the green/red region. Irradiating the devices in these wavelengths they produce photocurrents that are over 50% distinct between RCPL and LCPL. Fast transient responses (on the order of ms) of CPL are shown with possible logic operations, as well as humidity sensing. Films produced through the methods described in Chapter 3 show promis- ing properties for their application in sensing, co-templating, enantioselectivity, photonic pigments or anti-counterfeiting. The insights presented in Section 5.1 contribute to applications in solid-state ionics of mesoporous structures or the combination of optically active electrolytes capable of providing unique func- tionalities in ion-gated transistors and circuitry. Finally, the types of devices pro- duced in Section 5.2 and Chapter 6 may find applications in photonics, emission, conversion, or sensing with CPL but also imaging, spintronics, optoelectronic counterfeiting or information processing with logic states that depend solely on the handedness of the incident light.Esta dissertação é dedicada ao estudo de nanocristais de celulose (cellulose nanocrystals - CNCs) e à sua integração como filmes fotónicos em dispositivos optoelectrónicos, explorando a sua estrutura nemática quiral com orientação de rotação para esquerda como um filtro de luz polarizada circularmente (circu- lar polarized light - CPL) no comprimento de onda visível. Os resultados deste trabalho demonstram dispositivos microscópicos à base de celulose, capazes de responder com sinais elétricos específicos quando irradiados por CPL à esquerda (LCPL) ou CPL à direita (RCPL). Para esta prova-de-conceito são destacados dois dispositivos optoelectrónicos distintos: transístores e fotodíodos. Os dispositivos desenvolvidos incorporam diferentes tipos de CNCs com um hiato fotónico espe- cífico correspondente à região de absorção das camadas ativas dos dispositivos. De um lado são sintetizados CNCs em laboratório (home-made CNCs – HM-CNCs) que resultarão filmes fotónicos com um hiato no Azul/UV. De outro lado, CNCs comerciais da CelluForce (C-CNCs), em forma de pó. A redispersão desse tipo de CNCs em água é investigada, e resulta em filmes fotónicos com um hiato na região do verde/vermelho. Essencialmente, o trabalho está divido em três partes principais: • Estudo das propriedades líquidas cristalinas e fotónicas de suspensões aquo- sas de HM-CNCs e C-CNCs (Capítulo 3) • Implementação de HM-CNCs em transístores (Capítulo 5) • Implementação de C-CNCs em fotodíodos (Capítulo 6) Capítulo 5 estuda a implementação de filmes de HM-CNCs, otimizados no objetivo do Capítulo 3, em transístores de efeito de campo onde o semicondutor é o óxido de índio-gálio-zinco amorfo (a-IGZO). Nos dispositivos finais, o filme de HM-CNCs assume uma dupla funcionalidade: funciona como o dielétrico do transístor (na forma de um eletrólito de estado sólido), e atua como um filtro seletivo de CPL. Logo, esta parte está divida em dois sub-objetivos: a primeira estuda as propriedades eletroquímicas dos filmes de HM-CNCs, e a sua integração em transístores de efeito de campo sem perda das propriedades de self-assembly, enquanto a segunda parte é dedicada à prova de conceito da deteção seletiva de CPL. O estudo final demonstra a incorporação de filmes de C-CNCs em fotodíodos baseados em silício amorfo, que resulta em sensores de luz capazes de diferenciar entre os dois estados de CPL. A resposta espetral dos fotodíodos é máxima para comprimentos de onda específicos na região do verde e do vermelho. Ao irradiar os dispositivos finais nesses comprimentos de onda com CPL, estes apresentam uma diferença de 50% nas foto-correntes medidas para cada um dos dois estados de CPL. Os dispositivos finais mostram tempos de resposta rápidos (na ordem dos ms), o que os habilita a serem implementados em circuitos para operações lógicas baseadas em estados de polarização e também como sensores de humidade. Filmes produzidos no Capítulo 3, mostram propriedades promissoras para a sua aplicação em sensores, pigmentos fotónicos, e na área de anti-falsificação e segurança. Os resultados da Secção 5.1 contribuem para aplicações em iónica de estado sólido de estruturas mesoporosas, ou a combinação de eletrólitos ótica- mente ativos. Por fim, os dispositivos fabricados na Secção 5.2 e Capítulo 6, podem ser aplicados em áreas de fotónica, emissão, conversão ou sensores de CPL, mas também imagiologia, spintrónica, anti-falsificação por dispositivos optoelectró- nicos, ou processamento de informação com estados lógicos que dependem da polarização da radiação incidente

Institute of Archaeology & Horn Archaeological Museum Newsletter Volume 26.1

Annual at the Alamo, Paul J. Ray, Jr. Zadok Lecture, Matthew Grey Abila Lecture, Paul J. Ray, Jr. Al-Maktába: The Bookstore Random Surveyhttps://digitalcommons.andrews.edu/iaham-news/1021/thumbnail.jp

Understanding public attitudes towards organ donation: a media analysis

1. Following public consultations and the passing of the Human Transplantation (Wales) Bill in July 2013, a ‘deemed consent’ system for organ donation will be brought into effect in Wales on 1st December 2015 following a targeted communications campaign by the Welsh Government. This research report was commissioned by the Welsh Government in response to the findings of the Public Attitudes to Organ Donation: Baseline Survey 2012 (PAODBS; Welsh Government, 2012) which identified differences between regions in relation to both knowledge of the proposed changes in legislation and attitudes towards the new legislation, in order to inform targeted communications about the legislative change. These differences were not accounted for by socio-economic or demographic differences between these regions. 2. A retrospective content analysis of Welsh media coverage of organ donation legislation covering the period from October 2011 to April 2013 inclusive was carried out on sources from television, newspapers and social media in Wales. In addition to analysing message valence (positive or negative), source credibility and argument strength, an analysis of key themes identified within the sources was also conducted. 3. Analysis of television coverage in English and Welsh languages broadcasting across Wales on national television showed more positive than negative valence, with the pattern of reporting remaining broadly similar across English only, English and Welsh, and Welsh only sources. This suggests that regional differences in knowledge of, and attitudes towards, organ donation legislation are not due to differences in the way in which television stations in Wales convey information relating to organ donation legislation. 4. Themes relating to political and statistical health issues were the most dominant themes identified in television sources. Whilst both themes featured extensively in positive and negative items, political themes featured in more negative stories whilst statistical health themes were found in more positive stories. The television coverage analysed for this report shows a prevalence of factually objective stories relating to the organ donation legislation rather than religious, moral or emotionally laden themes. 5. Newspaper analysis provided mixed comparisons with the PAODBS. A balance of positive and negative items were identified in the Western Mail (accounting for just under half of items analysed) and in regional newspapers in North Wales. In contrast, a greater proportion of positive reporting was identified in the Swansea Bay and Mid & West Wales regional newspapers, and a greater proportion of negative reporting in the Cardiff & South-East Wales region. Positive themes reflected emotional, statistical and political information whilst negative themes reflected political, moral and religious themes. 6. The higher than average number of published letters from readers in the Western Mail and in newspapers within the Cardiff & South-East Wales region accounted for a high proportion of negative items in these data. Readers’ letters primarily reflect moral themes and, to a lesser extent, political and religious themes. 7. Overall, the coverage of organ donation legislation in Welsh media on television and in newspapers has been broadly balanced, with some regional exceptions. However, these in themselves do not explain the attitudes displayed by respondents to the PAODBS (2012). In conclusion, regional differences in knowledge of, and attitudes towards, organ donation legislation do not appear to reflect differences in the presentation of information relating to organ donation legislation across different types of media in Wales

Thalidomide upper limb embryopathy - : pathogenesis, past and present management and future considerations

Open Access via the Sage AgreementPeer reviewedPublisher PD

MP20, the second most abundant lens membrane protein and member of the tetraspanin superfamily, joins the list of ligands of galectin-3

BACKGROUND: Although MP20 is the second most highly expressed membrane protein in the lens its function remains an enigma. Putative functions for MP20 have recently been inferred from its assignment to the tetraspanin superfamily of integral membrane proteins. Members of this family have been shown to be involved in cellular proliferation, differentiation, migration, and adhesion. In this study, we show that MP20 associates with galectin-3, a known adhesion modulator. RESULTS: MP20 and galectin-3 co-localized in selected areas of the lens fiber cell plasma membrane. Individually, these proteins purified with apparent molecular masses of 60 kDa and 22 kDa, respectively. A 104 kDa complex was formed in vitro upon mixing the purified proteins. A 102 kDa complex of MP20 and galectin-3 could also be isolated from detergent-solubilized native fiber cell membranes. Binding between MP20 and galectin-3 was disrupted by lactose suggesting the lectin site was involved in the interaction. CONCLUSIONS: MP20 adds to a growing list of ligands of galectin-3 and appears to be the first representative of the tetraspanin superfamily identified to possess this specificity