Electrical Properties of Polymer Light-Emitting Devices

In this chapter, we present a brief introduction to semiconducting properties of conjugated polymers and the motivation to apply this class of materials in electronic/optoelectronic devices such as polymer light-emitting diodes (PLEDs). We describe, in detail, the operating mechanisms of PLEDs, with particular focus on the effects of charge injection and transport and their dependence on the external electric field and temperature. The mechanisms of current injection from the electrodes into the organic semiconductor are initially treated using traditional models for thermionic emission and tunnelling injection. More recent models considering the influence of metal/semiconductor interface recombination and of energetic and spatial disorder in the injection currents are also introduced and discussed. In addition, models considering space-charge-limited currents and trap-filling-limited currents are employed to describe the charge transport characteristics in the bulk. Furthermore, we present a brief discussion on ideas concerning the effects of the disorder on the charge-carrier transport behaviour

Box-ball systems and RSK recording tableaux

A box-ball system (BBS) is a discrete dynamical system consisting of n balls in an infinite strip of boxes. During each BBS move, the balls take turns jumping to the first empty box, beginning with the smallest-numbered ball. The one-line notation of a permutation can be used to define a BBS state. This paper proves that the Robinson-Schensted (RS) recording tableau of a permutation completely determines the dynamics of the box-ball system containing the permutation. Every box-ball system eventually reaches steady state, decomposing into solitons. We prove that the rightmost soliton is equal to the first row of the RS insertion tableau and it is formed after at most one BBS move. This fact helps us compute the number of BBS moves required to form the rest of the solitons. First, we prove that if a permutation has an L-shaped soliton decomposition then it reaches steady state after at most one BBS move. Permutations with L-shaped soliton decompositions include noncrossing involutions and column reading words. Second, we make partial progress on the conjecture that every permutation on n objects reaches steady state after at most n-3 BBS moves. Furthermore, we study the permutations whose soliton decompositions are standard; we conjecture that they are closed under consecutive pattern containment and that the RS recording tableaux belonging to such permutations are counted by the Motzkin numbers.Comment: 24 pages, 2 figure

Metodologia de ensino da educação física: repensando a ação do professor

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de ProduçãoO presente estudo buscou refletir sobre a questão da metodologia de ensino da Educação Física nas séries iniciais, considerando-se que a brincadeira infantil se configura como um elemento significativo na transmissão da cultura corporal para esse nível de ensino. Como instrumento para coleta dos dados, no trabalho de campo, foi utilizado um modelo de questionário estruturado. Quanto à amostra, considerou-se um grupo de sete docentes desta disciplina, que ministram aulas na rede privada nos município de Campo Largo, Colombo e Curitiba, no estado do Paraná. No instrumento de coleta de dados registrou-se a opinião dos profissionais sobre: a concepção e a importância desta área do conhecimento para as séries iniciais, o papel do professor nas séries iniciais e o papel das práticas corporais nesta fase da escolarizaçã

Electrical Characterization of Thin-Film Transistors Based on Solution-Processed Metal Oxides

This chapter provides a brief introduction to thin-film transistors (TFTs) based on transparent semiconducting metal oxides (SMOs) with a focus on solution-processed devices. The electrical properties of TFTs comprising different active layer compositions (zinc oxide, aluminum-doped zinc oxide and indium-zinc oxide) produced by spin-coating and spray-pyrolysis deposition are presented and compared. The electrical performance of TFTs is evaluated from parameters as the saturation mobility (μsat), the TFT threshold voltage (Vth) and the on/off current (Ion/Ioff) ratio to demonstrate the dependence on the composition of the device-active layer and on ambient characterization conditions (exposure to UV radiation and to air)

Optimization of the Anodization Processing for Aluminum Oxide Gate Dielectrics in ZnO Thin Film Transistors by Multivariate Analysis

The present study reports a two-level multivariate analysis to optimize the production of anodized aluminum oxide (Al₂O₃) dielectric films for zinc oxide thin-film transistors (TFTs). Fourteen performance parameters were measured and analysis of variance (ANOVA) of the combined responses has been applied to identify how the Al₂O₃ dielectric fabrication process influences the electrical properties of the TFTs. Using this approach, the levels for the manufacturing factors to achieve optimal overall device performance have been identified and ranked. The cross-checked analysis of the TFT performance parameters demonstrated that the appropriate control of the anodization process can have a higher impact on TFT performance than the use of traditional methods of surface treatment of the dielectric layer. Flexible electronics applications are expected to grow substantially over the next 10 years. Given the complexity and challenges of new flexible electronics components, this “multivariate” approach could be adopted more widely by the industry to improve the reliability and performance of such devices

UV phototransistors based upon spray coated and sputter deposited ZnO TFTs

A comparison of Zinc Oxide (ZnO) phototransistors prepared by spray and sputter coating process is presented. The work shows that spray coated layers provide significant advantages in sensor response over ZnO phototransistors made by physical vapour deposition and we show that spray deposited ZnO phototransistors can exhibit state-of-the-art performances for UV photodetectors. Topographic images of the samples surface shows that there is increase in surface roughness in spray coated samples indicating increasing grain sizes, which is considered the source of the greater sensor responsivity. X-ray photoelectron spectroscopy (XPS) is also used to understand the root cause of the greater UV responsivity. It was observed that sprayed ZnO TFTs are more sensitive to UV radiation due to higher adsorption of oxygen level. Responsivity and external quantum efficiency (EQE) of the sprayed and sputtered ZnO TFTs are also evaluated

Evolução da Produção Científica em Contabilidade no Brasil: Uma análise da IES no período de 2010 a 2018: Evolution of Scientific Production in Accounting in Brazil: An analysis of the IES in the period from 2010 to 2018

Este artigo analisa e pontua o perfil de publicação das dissertações de mestrado de uma IES no período de 2010 a 2018. Para a elaboração fez-se o uso de uma metodologia descritiva, quantitativa, bibliográfica e documental, além de ser caracterizado como estudo bibliométrico. Do total de 206 dissertações publicadas e defendidas, 118 foram identificadas como de contabilidade. A análise indicou que o gênero predominante nas publicações é o masculino, os orientadores com maior número de orientações são Dr Ivam R. Peleias, Dr Marcos R. S. Pertes e Dr Claudio Parisi. A pesquisa apresentou 19 categorias de assunto, predominando Contabilidade Gerencial, Societária e Educação e Ensino. Na metodologia evidenciou-se um maior número de pesquisas com abordagem qualitativa. Identificou-se ainda 46 categorizações e combinações dos procedimentos metodológicos

Revista digital

Orientador: Jeroniza Nunes MarchaukoskiMonografia (graduação) - Universidade Federal do Paraná, Escola Técnica, Curso de Tecnologia em InformáticaInclui bibliografi