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Made available in DSpace on 2022-04-29T08:46:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Few works on solution-processed zinc oxide vertical transistors and electrolyte-gated transistors have shown the merits of both architectures. Here, we present an electrolyte-gated vertical field-effect transistor (EGVFET) based on a spray-deposited zinc oxide/silver nanowire (ZnO/AgNW) Schottky contact. The output curve shows that the device operates at a sub-1 V bias. Also, the electrolyte does not affect the diode cell, and the cyclic voltammetry of the capacitor cell does not indicate a faradic process between AgNW and the top-gate electrode. From the transfer curve, we extracted an ION/IOFF ratio of 104, an on-current density of 65.3 mA/cm2 and a normalized transconductance of 113.4 S/cm2. Our contribution places the ZnO-EGVFET structure on the front line to develop printed transistors without a high-resolution pattern. São Paulo State University – UNESP, Faculty of Science and Technology (FCT), Physics Department, Presidente Prudente, SP, Brazil. (e-mail: leonardo.nogueira@unesp.br) São Paulo State University – UNESP, Faculty of Science and Technology (FCT), Physics Department, Presidente Prudente, SP, Brazil. Universidade Federal do Paraná – UFPR, Physics Department, Curitiba, PR, Brazil. Universidade Tecnológica Federal Do Paraná – UTFPR, Physics Department, Curitiba, PR, Brazil.

Made available in DSpace on 2021-06-25T11:10:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Here we present the study of supercapacitors based on molybdenum disulfide and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (MoS2/PEDOT:PSS) composite electrodes deposited by spray-coating. To produce the MoS2/PEDOT:PSS composite ink, dispersions of hydrothermally synthesized MoS2 and PEDOT:PSS were mixed in different weight proportions. Electrodes containing only PEDOT:PSS and MoS2 were also fabricated for comparison. The composite films were deposited by transferring the as-prepared inks to an airbrush coupled to a modified 3D printer base with in-line displacement. The films were characterized in terms of the scanning electron microscope (SEM), Raman spectroscopy, and sheet resistance. The electrochemical properties of supercapacitors were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharges (GCD) techniques, impedance spectroscopy (IS), and their correlated parameters. The maximum specific capacitance of the MoS2-based supercapacitor was estimated to be 145.9 F g−1 at 1 mV s−1, while the 3:1 MoS2/PEDOT:PSS weight ratio supercapacitor exhibited a specific capacitance of 131.1 F g−1. Despite the slightly lower CSP, the 3:1 device provided a better overall performance, with a remarkably higher energy density of 11.2 Wh kg−1 and a maximum power density of 1020 W kg−1. It also displayed better long-term cycle stability, retaining 92% of its initial capacitance after 1000 CV cycles (against 54% of MoS2 devices). In summary, we demonstrated the study and production of a high-performance supercapacitor with spray-deposited MoS2/PEDOT:PSS composite electrodes, in which the production can be easily scalable for mass production and practical applications. School of Technology and Sciences São Paulo State University (UNESP) School of Technology and Sciences São Paulo State University (UNESP) FAPESP: 2018/02604-4

Made available in DSpace on 2021-06-25T11:06:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 $\beta $ -Ga2O3 is one of the promising semiconductor materials that has been widely used in power electronics and ultraviolet (UV) detectors due to its wide bandgap and high sensitivity to UV light. Specifically, for the UV detection application, it has been reported that the photocurrent was in the scale of microamps ( $\mu \text{A}$ ), which normally requires sophisticated signal processing units. In this work, a novel approach based upon coupling of two Schottky diodes is reported, leads to a substantial increase in photocurrent (186 times) when benchmarked against a conventional planar UV photodiode. The detectivity and responsivity of the new device have also been significantly increased; the rectification ratio of this device was measured to be $1.7\times 10^{7}$ with ultralow dark current, when measured in the reverse bias. The results confirm that the approach of coupling two Schottky diodes has enormous potential for improving the optical performance of deep UV sensors. Departamento de Fisica UNESP - Sao Paulo State University Multidisciplinary Nanotechnology Centre College of Engineering Swansea University School of Electronic Engineering Bangor University Departamento de Fisica UNESP - Sao Paulo State University

Made available in DSpace on 2020-12-12T02:46:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-15 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. School of Electronics Bangor University School of Technology and Sciences São Paulo State University (Unesp) Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) Rio Claro Faculty of Science and Engineering University of Chester School of Technology and Sciences São Paulo State University (Unesp) Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) Rio Claro

Made available in DSpace on 2022-05-01T13:41:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-01 Printed electronics is a reputable research area that aims at simple alternatives of manufacturing low-cost, eco-friendly, and biodegradable electronic devices. Among these devices, electrolyte-gated transistors (EGTs) stand out due to their simple manufacturing process and architecture. Here we report the study of printed EGTs with in-plane gate transistor (IPGT) architecture based on zinc oxide nanoparticles. The drain, source, and gate electrodes with two different W/L channel ratios were fabricated using a screen-printed carbon-based ink. We also produced a conventional top-gate transistor as a standard device, using the same structure of the IPGT described above with the addition of an indium tin oxide strip positioned over the electrolyte as the top-gate electrode. The IPGT with W/L = 5 presented a high mobility of 7.95 0.55 cm2 V-1 s-1, while the W/L = 2.5 device exhibited a mobility of 3.03 0.52 cm2 V-1 s-1. We found that the measured field-effect mobility of the device can be affected by the high contact resistance from the carbon electrodes. This effect could be observed when the device's geometric parameters were changed. Furthermore, we also found that the IPGT with W/L = 5 exhibited higher values for mobility and transconductance than the top-gate transistor, showing that the IPGTs architecture is a good approach for cheap and printed transistors with performance comparable to standard top-gate EGTs. School of Technology and Sciences Department of Physics S o Paulo State University - UNESP, SP Faculty of Science and Technology (FCT) CENIMAT/I3N Department of Materials Science Universidade NOVA de Lisboa CEMOP-UNINOVA School of Technology and Sciences Department of Physics S o Paulo State University - UNESP, SP

Made available in DSpace on 2022-04-29T08:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Theprinted electronics presents the outstanding proposal to produce low-cost, solution-processable, vacuum-free and flexible devices. In this context, many researchers have been made efforts to obtain printed memories that works with low voltage bias, high on/off ratio and storage stability. Here, we report a novel low-cost printed version of a memristor based on spray coated films of indigo and colloidal graphite. This memory showed high performance for printed memristors, being the most remarkable aspect of this device its high on/off ratio of 1.6 × 106 at -1.15 V, and 3.1 × 104 for voltages as low as +0.1 V. The pulse-test mode read at +0.1 V revealed very stable endurance characteristics even after 100 readings and retention time over 104 s, as desired by the printed electronics niches. The Physics Department Faculty of Science and Technology (FCT) São Paulo State University - UNESP, São Paulo The Physics Department Faculty of Science and Technology (FCT) São Paulo State University - UNESP, São Paulo FAPESP: 2019/03934-0 FAPESP: 2020/12282-4

Made available in DSpace on 2020-12-12T01:42:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Successful manufacture of a simple, low cost sprayed Schottky diode compatible with printed electronics using reduced graphene oxide (rGO) as a semi-transparent top electrode and zinc oxide (ZnO) as active layer has been reported in this paper. The rGO was synthesized using modified Hummers’ method and deposited by spray coating. The transmittance analyses of rGO films shows 62.3% transparency for ultraviolet (UV) light and by the Van der Pauw method shows sheet resistance of 19 kΩ/□. The rGO electrode provides an alternative to expensive metallic electrodes such as Au, Pt, Pd and Ag which are not ecofriendly. Furthermore, rGO performs Schottky contact with sprayed zinc oxide film resulting in a diode with the sequence of deposited layers Al/ZnO/rGO and low turn-on voltage that has current–voltage characteristics whose rectifying behavior is affected by the incidence of UV light resulting in a possibility to use that diode as photodetector for this kind of radiation. Departamento de Física Faculdade de Ciências e Tecnologia UNESP Departamento de Física Universidade Federal de Juiz de Fora Departamento de Física Faculdade de Ciências e Tecnologia UNESP

Made available in DSpace on 2021-06-25T10:33:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Instituto Nacional de Ciência e Tecnologia em Eletrônica Orgânica Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The UV photocurrent response of thin films of wide bandgap semiconductors such as zinc oxide (ZnO) can be applied to a great number of electronic devices aiming applications in environmental sensing or UV-detection. Electronic devices like thin-film transistors or Schottky diodes commonly present multiple parameters of electrical characteristic, which can be beneficially exploited to provide more information than sensors based on purely resistive or capacitive response. We manufactured Schottky diodes using spray-coated ZnO and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as an easy, simple and low-cost method for producing multiparametric UV-photodetectors. The diode parameters presented rectification ratios (RR) as high as 104 and ideality factors as low as 1.3, and their characteristic curves were analyzed by Cheung's method to determine the effect of UV irradiation on the ideality factor, series resistance and Schottky barrier height. The study of the photocurrent response from spray-coated ZnO films as a function of geometric parameters and UV intensity demonstrated a transition from bimolecular to monomolecular recombination process at higher irradiance values, as a result of the adsorption/desorption dynamics of molecular oxygen at the semiconductor/air interface. São Paulo State University – UNESP Faculty of Science and Technology (FCT) Physics Department São Paulo State University – UNESP Institute of Geosciences and Exact Sciences (IGCE) Physics Department São Paulo State University – UNESP Faculty of Science and Technology (FCT) Physics Department São Paulo State University – UNESP Institute of Geosciences and Exact Sciences (IGCE) Physics Department FAPESP: 2018/04169-3 FAPESP: 2019/01671-2 FAPESP: 2019/08019-9

Made available in DSpace on 2022-05-01T09:47:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Here we report the production and characterization of a low-cost supercapacitor with electrodes based on colloidal graphite. We characterized the as-prepared device in terms of cyclic voltammetry (CV), Galvanostatic charge/discharge (GCD), and impedance spectroscopy. The supercapacitor exhibited good electrochemical performance with a high capacitance of 22 F g-1for a discharge current of 2 mA. Long-term cyclability tests show that the device can keep about 85% of its capacitance after 500 cycles, even without encapsulation. We found power and energy densities of 110 W kg-1and 3 Wh kg-1, respectively. All the experimental results indicate that the colloidal graphite Aquadag® is a promising material for application in supercapacitors. Universidade Estadual Paulista (UNESP) Faculdade de Tecnologia e Ciências, SP Universidade Estadual Paulista (UNESP) Faculdade de Tecnologia e Ciências, SP

β-Ga 2 O 3 is a promising semiconductor for electronic devices. In the present work we have demonstrated a novel method for manufacturing a β-Ga 2 O 3 Schottky diode, in which the same electrode material is used for both contacts. The device is tested it for its applicability in deep UV sensing. Devices were manufactured directly onto β-Ga 2 O 3 (010) wafer material. From the perspective of diode performance, a high rectification ratio of 1.5x107 and high forward current of 17.58 mA/cm2 at −5 V bias was obtained. A responsivity of 12.5 mA/W was recorded when irradiated with light possessing a wavelength of 254 nm. Importantly, detailed analysis is conducted in order to evaluate the performance of the Schottky diode using Cheung’s and Norde’s methods allowing for accurate calculation of the Schottky barrier height in this device.

Made available in DSpace on 2020-12-12T02:43:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Universidade Estadual Paulista Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Aluminum-oxide (Al2O3) is a low cost, easily processable and high dielectric constant insulating material that is particularly appropriate for use as the dielectric layer of thin-film transistors (TFTs). Growth of aluminum-oxide layers from anodization of metallic aluminum films is greatly advantageous when compared to sophisticated processes such as atomic layer deposition (ALD) or deposition methods that demand relatively high temperatures (above 300 °C) such as aqueous combustion or spray-pyrolysis. However, the electrical properties of the transistors are highly dependent on the presence of defects and localized states at the semiconductor/dielectric interface, which are strongly affected by the manufacturing parameters of the anodized dielectric layer. To determine how several fabrication parameters influence the device performance without performing all possible combination of factors, we used a reduced factorial analysis based on a Plackett-Burman design of experiments (DOE). The choice of this DOE permits the use of only 12 experimental runs of combinations of factors (instead of all 256 possibilities) to obtain the optimized device performance. The ranking of the factors by the effect on device responses such as the TFT mobility is possible by applying analysis of variance (ANOVA) to the obtained results. School of Technology and Sciences São Paulo State University-UNESP Scholl of Electronic Engineering Bangor University Institute of Geosciences and Exact Sciences São Paulo State University-UNESP School of Technology and Sciences São Paulo State University-UNESP Institute of Geosciences and Exact Sciences São Paulo State University-UNESP FAPESP: 14/13904-8 FAPESP: 16/03484-7 FAPESP: 19/01671-2 FAPESP: 19/05620-3 FAPESP: 19/08019-9

Este artigo discute a articulação entre o fazer literário e a condição biográfica do sujeito autoral proposta por Conceição Evaristo no seu conceito da Escrevivência. Buscamos evidenciar a escre(vivência) da Chimamanda Ngozi Adichie, mulher negra nigeriana que inscreve no corpus literário contemporâneo uma forma contundente de auto-representação individual e coletiva, presente no registro ficcional de questões raciais e de gênero apresentados no romance “Americanah” (2013). Analisamos essa possibilidade de reflexão sobre o papel da mulher negra enquanto escritora, verificando as operações estéticas a partir das quais elas articulam as intervenções da vida sobre a palavra escrita e vice-versa.

Made available in DSpace on 2018-12-11T17:36:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Abstract: We report a process for performing the middle electrode for a vertical field effect transistor (VOFET) by the evaporation of a tin (Sn) layer. Bare aluminum oxide (Al2O3), obtained by anodization, and Al2O3 covered with a polymethylmethacrylate (PMMA) layer were used as the gate dielectric. We measured the electrical resistance of Sn while the evaporation was carried out to find the best condition to prepare the middle electrode, that is, good lateral conduction associated with openings that give permeability to the electric field in a vertical direction. This process showed that 55 nm Sn thick is suitable for use in a VOFET, being easier to achieve optimal thickness when the Sn is evaporated onto PMMA than onto bare Al2O3. The addition of a PMMA layer on the Al2O3 surface modifies the morphology of the Sn layer, resulting in a lowering of the threshold voltage. The values of threshold voltage and electric field, VTH = − 8 V and ETH = 354.5 MV/m respectively, were calculated using an Al2O3 film 20 nm thick covered with a 14 nm PMMA layer as gate dielectric, while for bare Al2O3 these values were VTH = − 10 V and ETH = 500 MV/m. Graphical Abstract: [Figure not available: see fulltext.]. School of Technology and Applied Sciences São Paulo State University (UNESP) School of Technology and Applied Sciences São Paulo State University (UNESP) FAPESP: 2013/26973-5 FAPESP: 2014/13015-9

This study investigated whether women with patellofemoral pain (PFP) present kinematic alterations in proximal, local, and distal factors simultaneously, and determined the association between the number of kinematic alterations, pain level, and functional status. A three-dimensional motion analysis system was used to analyze the peak hip adduction, peak knee flexion, and peak rearfoot eversion, addressing the proximal, local, and distal factors, respectively, in fifty women. Functional status and pain level were assessed using the anterior knee pain scale (AKPS) and a visual analogic scale. Receiver operating characteristic curves were calculated to identify participants with and without kinematic alterations and the number of them was obtained for each participant. Associations between the number of kinematic alterations, pain level, and AKPS score were determined by the Pearson correlation. Results showed that 52% of women with PFP presented at least two kinematic alterations of which 24% were local/proximal, 16% local/distal, and 12% proximal/distal. Three kinematic alterations were found in 48% of the women with PFP. A strong positive correlation was found between the number of kinematic alterations and pain (r=0.78; p

Made available in DSpace on 2022-04-29T08:32:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Instituto Nacional de Ciência e Tecnologia em Eletrônica Orgânica Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) is a promisor p-type solution-processable molecular semiconductor whose electrical properties are highly dependent on its morphology. Unfortunately, there is a great difficulty in controlling the TIPS-pentacene crystallization because it is extremely affected by many factors, as the deposition method, the solvent type, and others. Here, we studied thin-films of TIPS-pentacene blending with poly(3-hexylthiophene-2,5-diyl) (P3HT:TP blend) in different ratios, aiming to improve TIPS-pentacene morphology. The surface of each film was very dependent on the deposition method and the blend morphology exhibited a high variation with the ratio. The different crystallinities achieved lead to dramatic changes in the charge carrier transport properties throughout the film. The impedance spectroscopy indicated that the small addition of P3HT in the TIPS-pentacene greatly improves its conductivity, however, the TIPS-pentacene forms crystallite agglomerates that did not percolate, prevailing the P3HT conductivities. São Paulo State University – UNESP Faculty of Science and Technology (FCT) Physics Department São Paulo State University – UNESP Faculty of Science and Technology (FCT) Physics Department CAPES: 001 FAPESP: 2020/12282-4

Made available in DSpace on 2022-04-29T08:36:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Paper electronics has emerged as an ecofriendly, light, low-cost, and recyclable material for the fabrication of flexible and printed transistors. In this study, we present fully printed organic electrochemical transistors using an active layer of PEDOT:PSS, carbon electrodes, cellulose-based electrolyte, and three different papers as substrates: bond, vegetal, and Lumi Silk, relating the electrical properties to the different morphologies of the paper surfaces. Each paper presents different regularity, diffusion capabilities, and roughness, with significant influence on the transistor performance. The more organized and smooth the surface, the better the electrical characteristics, the best of these being the Lumi Silk, with higher I on/I off ratio of 46, on-current of 8.3 10-5 A, V on of 1.3 V, and power gain of 43.5 dB associated with ultra-low hysteresis of 0.1 V, high transconductance of -57.3 μS, and suitablity for flexible electronics and sensors applications. S o Paulo State University - UNESP Faculty of Science and Technology (FCT) Physics Department, SP Universidade NOVA de Lisboa and CEMOP-UNINOVA Faculty of Science and Technology (FCT) CENIMAT/I3N Department of Materials Science S o Paulo State University - UNESP Faculty of Science and Technology (FCT) Physics Department, SP

Orientador: Christiano Key Tambascia Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas Resumo: Nesta dissertação, acompanho o processo de consolidação da antropologia no Brasil a partir da obra e dos intercâmbios acadêmicos de um pesquisador central para a institucionalização da mesma: Emilio Willems. Sendo o primeiro professor a ocupar a cadeira de antropologia na USP e tendo ocupado posições de destaque nas Ciências Sociais do país, Willems teve um percurso ímpar no desenvolvimento da disciplina. Partindo de sua formação na Alemanha, seu papel institucional na antropologia brasileira na década de 1940, e sua trajetória acadêmica nos EUA, procuro mostrar a trajetória do professor nos três países e sua concepção de ensino e pesquisa nos estudos no e sobre o Brasil Abstract: In this dissertation, I go through the process of the consolidation of anthropology in Brazil. This was made based on the work and academic exchanges of a central researcher for its institutionalization: Emilio Willems. Being the first professor to occupy the chair of anthropology at USP and having held prominent positions in the country's Social Sciences, Willems had a unique path in the development of the discipline. Starting from his education in Germany, his institutional role in Brazilian anthropology in the 1940s, and his academic trajectory in the USA, I discuss the trajectory of the professor in the three countries and his conception of teaching and research in studies in and about Brazil Mestrado Antropologia Social Mestre em Antropologia Social CAPES 001

Made available in DSpace on 2019-10-06T17:13:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-30 Zinc acetate dihydrate solution was deposited onto glass and a thin layer of aluminum (10 nm), by spray pyrolysis at 450 °C, growing zinc oxide (ZnO) thin films. The ZnO formation occurs differently on aluminum due to the diffusion process forming AZO at the Al/ZnO interface. The films deposited onto the aluminum showed transmittance above 95%, associated with sheet resistance less than 40 Ω/sq. The high transmittance value with low sheet resistance is crucial for a good transparent electrode. Raman spectroscopy showed a higher degree of doping for films with thin layers of ZnO, and that the diffusion process is high at the Al/ZnO interface. The performance of the transparent electrode was evaluated through the characterization of the Schottky diode (Al:ZnO/ZnO/Au). The factor of ideality (n), resistance in series (Rs), and height of the barrier (ϕB) presented values of 3.79, 1022.6 Ω, and 0.97 eV, respectively. These results demonstrate the simple production of a transparent electrode by the in situ diffusion process using the spray pyrolysis technique. School of Technology and Applied Sciences São Paulo State University (UNESP) School of Technology and Applied Sciences São Paulo State University (UNESP)

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 perf...

Made available in DSpace on 2018-12-11T17:02:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-01 Poly(3-hexylthiophene):6,13-bis(triisopropylsilylethynyl)-pentacene (P3HT:TP) blends with a ratio of 1:1 (wt/wt) were deposited via spin coating on anodized oxide (Al2O3). A phase separation of the compounds was observed, resulting in the formation of crystalline aggregates of TP molecules that segregate vertically on the surface. The form of segregation depends on the oxide surface treatment used. Spectroscopy analysis shows a higher molecular order of P3HT in the blend than for neat film and that TP molecules are also distributed in the polymeric matrix. Regarding the OFET characteristics, charge carrier mobilities of 1.2 × 10- 3 cm2 V- 1 s- 1 and 2.0 × 10- 3 cm2 V- 1 s- 1 were obtained from devices for untreated and (hexamethyldisilazane) HMDS-treated Al2O3 gate dielectric, respectively. These results confirm that P3HT:TP blends have good potential as an active layer in organic field effect transistors (OFETs). Faculdade de Ciências e Tecnologia UNESP - Univ Estadual Paulista Departamento de Física Faculdade de Ciências e Tecnologia UNESP - Univ Estadual Paulista Departamento de Física

Made available in DSpace on 2019-10-06T16:54:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Here we describe a screen-printed supercapacitor produced onto filter paper using poly (3, 4-ethylene dioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS)/multiwall carbon nanotube (MWCNT) composite as active materials. We use a gel-like electrolyte based on poly (vinyl alcohol) and phosphoric acid (PVA/H3PO4), serving as both an ionic conductor and as an electrode separator. The electrodes are physically characterized through micro-Raman scattering analyses, sheet resistance measurements as a function of the printed number of layers and through scanning electron microscopy. The supercapacitor performance is investigated through impedance spectroscopy, equivalent circuit fitting, cyclic voltammetry (CV), long-term cycle stability and galvanostatic charge/discharge. The electrodes exhibit a low sheet resistance, reaching 17 Ω sq−1, being suitable for use as both electrode and the current collector. The supercapacitor shows good capability behavior over impedance spectroscopy and CV measurements, and 72% of capacitance retention after 1000 cycles. We find a maximum specific capacitance of 20,3 F g−1 for a charge/discharge current of 1 mA, and equivalent series resistance of 60 Ω leading to energy and power densities of 3,1 Wh kg−1 and 420 W kg−1, respectively. In conclusion, we describe here a flexible supercapacitor without metal collectors produced by a simple printing method. São Paulo State University (UNESP) School of Technology and Applied Sciences São Paulo State University (UNESP) School of Technology and Applied Sciences FAPESP: 2015/18091-8 FAPESP: 2018/02604-4

Zinc oxide (ZnO) thin film transistors are well suited to UV sensing application because they absorb predominantly in the UV region due to the wide bandgap (Eg = 3.37 eV) and possess a large exciton binding energy (60 meV) with high radiation hardness. When operated as a transistor, many device performance parameters alter such as threshold Voltage, on-off current and channel mobility. As a result, it is to distinguish between changes in electrical performance induced by UV light and environmental effects that add noise to the sensor performance. In this work, the UV response of zinc oxide thin film transistors (ZnO TFTs) is examined using Taguchi Design of Experiment (DOE) method. By using this multivariate analysis approach, it is possible to reduce the number of calibration tests required for the sensor to accurately assess UV irradiation It is observed that different input conditions (UV power, exposure time, temperature, bias conditions) affect different TFT performance parameters more or less significantly. From the perspective of UV sensing, ON current in the saturation region appears to be the best performance parameter in a ZnO TFT for examining differences in UV exposure.

Made available in DSpace on 2018-12-11T17:35:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 The production of low cost sensors to monitor environment in some industrial sectors is a current need. In aviculture centers, for example, the concentration of ammonia gas is related to humidity, and it is necessary to control it to avoid contamination. With this need in mind, this paper presents the preparation and characterization of a low cost humidity sensor based on poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) and polyaniline fully printed onto paper by a commercial HP printer. Using electrochemical impedance spectroscopy, an equivalent circuit containing resistive and capacitive parameters was proposed. The resistive parameter R1 is related to values of ambient humidity. The R1 values showed a sensitive response of 200% when relative humidity changes 80%, taking 10 min to reach saturation point. Moreover, the device showed good stability when humidity remained constant. These results indicate that the proposed device is suitable for applying as a humidity sensor that costs less than 1 Euro cent. School of Technology and Sciences São Paulo State University (UNESP) School of Technology and Sciences São Paulo State University (UNESP)

Made available in DSpace on 2018-12-11T17:16:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The use of paper as a platform to manufacture organic electronic devices, electronic paper, has expanding potential for many applications because of several properties offered. In this work, we show a study of PEDOT:PSS printed by inkjet on bond paper, vegetal paper and sheets of PET. The relation between the surface density of the deposited material, morphology and resistivity was investigated for samples printed with a commercial Hewlett-Packard(HP)® printer and Microsoft Word® software. The amount of material deposited, i.e. surface density, was controlled using the print number in the same position and changing the gray scale used in the image formation. Changing the surface density of printed PEDOT:PSS, it is possible to produce a continuous film permeating the papers fibers. Sheet resistances obtained, when 7.0 mg cm−2 of PEDOT:PSS were deposited on the surfaces, were: (a) 413.2 kΩ/Sq for bond paper, (b) 5.6 kΩ/Sq for vegetable paper and (c) 2.3 kΩ/Sq for PET. The exponential dependence of sheet resistance with the surface density of printed material allows us to evaluate the strong influence of substrate roughness on PEDOT:PSS conductivity and to predict, for each one, conditions to minimize it. São Paulo State University (UNESP) School of Technology and Applied Sciences Campus Presidente Prudente São Paulo State University (UNESP) School of Technology and Applied Sciences Campus Presidente Prudente

Este artigo apresenta os resultados de uma pesquisa realizada com alunos do ensino médio referente aos temas: polímeros, plásticos e reciclagem. A intervenção buscou fornecer elementos para conscientização e reflexão sobre problemas ambientais, além de despertar nos alunos um pensamento crítico. Dentre as etapas da pesquisa estão o levantamento dos conhecimentos prévios, obtidos por meio de um questionário, além de ações de informação e conscientização implementadas através de um seminário ministrado sobre o tema. A inferência dos resultados apresenta-se como uma alternativa de ensino interessante para educação escolar, uma vez as propostas de ações sugeridas pelos alunos, revelam uma dimensão social que extrapola os “muros” escolares.

Background Excessive rearfoot eversion is thought to be a risk factor for patellofemoral pain development, due to the kinesiological relationship with ascendant adaptations. Individuals with patellofemoral pain are often diagnosed through static clinical tests, in scientific studies and clinical practice. However, the adaptations seem to appear in dynamic conditions. Performing static vs. dynamic evaluations of widely used measures would add to the knowledge in this area. Thus, the aim of this study was to determine the reliability and differentiation capability of three rearfoot eversion measures: rearfoot range of motion, static clinical test and static measurement using a three-dimensional system. Method A total of 29 individuals with patellofemoral pain and 25 control individuals (18–30 years) participated in this study. Each subject underwent three-dimensional motion analysis during stair climbing and static clinical tests. Intraclass correlation coefficient and standard error measurements were performed to verify the reliability of the variables and receiver operating characteristic curves to show the diagnostic accuracy of each variable. In addition, analyses of variance were performed to identify differences between groups. Findings Rearfoot range of motion demonstrated higher diagnostic accuracy (an area under the curve score of 0.72) than static measures and was able to differentiate the groups. Only the static clinical test presented poor and moderate reliability. Other variables presented high to very high values. Interpretation Rearfoot range of motion was the variable that presented the best results in terms of reliability and differentiation capability. Static variables do not seem to be related to patellofemoral pain and have low accuracy values.

Made available in DSpace on 2015-10-22T07:18:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-01. Added 1 bitstream(s) on 2015-10-22T09:46:00Z : No. of bitstreams: 1 WOS000347696500011.pdf: 661717 bytes, checksum: 8be94e4a0664ccdb5e47a823a7e099ca (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) INEO (Brazil) The effects of humidity on the electrical properties of thermal inkjet-printed copper tetrasulfonated phthalocyanine (CuTsPc) films onto paper substrates are reported. DC electrical measurements revealed that sample resistance decreases from 10(12) Omega in moderate vacuum to approximately 10(7) Omega at highly water-saturated atmosphere. This behavior is attributed to the creation of water pathways on the cellulose fibers that allow ionic species such as impurities, protons (H+), and dissociated Na+ ions from the CuTsPc molecules, to flow. The contribution of the CuTsPc molecules and their dissociated Na+ ions on the sample resistance was elucidated analyzing the electrical response of bare and printed paper substrates. An increase of relative humidity levels (RH) from 10 % to 40-45 % revealed an increase of current of four orders of magnitude for printed samples, whereas less than one order of magnitude was registered for bare paper substrates. Electrical measurements as a function of temperature have shown that moisture can inhibit the semiconducting properties of CuTsPc. Thermal gravimetric studies revealed that approximately 11 % of mass accounting to the presence of water is released above 70 A degrees C, the same temperature in which the sample recovers its dry-state semiconducting behavior. The semiconducting properties of CuTsPc can also be observed upon white light illumination, whereas the charge carrier extraction is governed by the RH level. These results point out the important role of humidity on the electrical properties of paper-based organic, electronic, and optoelectronic devices. Universidade Estadual Paulista (UNESP), Faculdade de Ciências e Tecnologia, BR-19060900 Presidente Prudente, SP, Brasil Instituto Federal de Educação, Ciência e Tecnologia de Santa Catarina (IFSC), BR-89245000 Araquari, SC, Brasil Universidade Estadual Paulista (UNESP), Faculdade de Ciências e Tecnologia, BR-19060900 Presidente Prudente, SP, Brasil

Made available in DSpace on 2015-11-03T15:29:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-01. Added 1 bitstream(s) on 2015-11-04T10:16:12Z : No. of bitstreams: 1 S1516-14392014000600014.pdf: 3036693 bytes, checksum: 9c10b6735a0dbb7c9618b86666398c6d (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) INEO (Brazil) Thermal inkjet-printing of copper tetrasulfonated phthalocyanine (CuTsPc) films containing polyvinyl alcohol (PVA) plasticizer were used to fabricate flexible metal-insulator-semiconductor (MIS) capacitors using anodic aluminum oxide (Al2O3) as the insulating layer. The Al2O3 layer and printed CuTsPc+PVA films were characterized individually and in a MIS structure by electrical impedance spectroscopy. Capacitance-frequency and capacitance-voltage measurements revealed distinct contributions from CuTsPc and PVA on the device electrical response. From these measurements the semiconductor charge carrier mobility, mu, of 1.22x10(-4) cm(2) V-1 s(-1) and the doping density, N A, of 3.1x10(16) cm(-3) were calculated. It was observed a low-frequency electrical response, which was attributed to diffusional processes within the printed film arising from Na+ ions dissociated from the CuTsPc molecule. A simple equivalent circuit model was proposed to take this effect into account. Finally, the results shown here demonstrate the possibility to produce flexible organic electronic devices exploiting the semiconducting properties of water-soluble CuTsPc molecules using low-cost commercial printers. Sao Paulo State Univ UNESP, Fac Sci &Technol, Dept Phys Chem &Biol, Presidente Prudente, SP, Brazil Fed Inst Educ Sci &Technol Santa Catarina IFC, Araquari, SC, Brazil Sao Paulo State Univ UNESP, Fac Sci &Technol, Dept Phys Chem &Biol, Presidente Prudente, SP, Brazil

To assess the diagnostic accuracy of the surface electromyography (sEMG) parameters associated with referred anterior knee pain in diagnosing patellofemoral pain syndrome (PFPS).Sensitivity and specificity analysis.Physical rehabilitation center and laboratory of biomechanics and motor control.Pain-free subjects (n=29) and participants with PFPS (n=22) selected by convenience.Not applicable.The diagnostic accuracy was calculated for sEMG parameters' reliability, precision, and ability to differentiate participants with and without PFPS. The selected sEMG parameter associated with anterior knee pain was considered as an index test and was compared with the reference standard for the diagnosis of PFPS. Intraclass correlation coefficient, SEM, independent t tests, sensitivity, specificity, negative and positive likelihood ratios, and negative and positive predictive values were used for the statistical analysis.The medium-frequency band (B2) parameter was reliable (intraclass correlation coefficient=.80-.90), precise (SEM=2.71-3.87 normalized unit), and able to differentiate participants with and without PFPS (P.05). The association of B2 with anterior knee pain showed positive diagnostic accuracy values (specificity, .87; sensitivity, .70; negative likelihood ratio, .33; positive likelihood ratio, 5.63; negative predictive value, .72; and positive predictive value, .86).The results provide evidence to support the use of EMG signals (B2-frequency band of 45-96 Hz) of the vastus lateralis and vastus medialis muscles with referred anterior knee pain in the diagnosis of PFPS.

Made available in DSpace on 2018-12-11T17:26:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This paper reports on the analysis of dispersion in the imaginary part of impedance often observed at low frequencies in a variety of systems. The experimental data were obtained with an electrolytic cell containing KCl aqueous solution in the frequency range from 0.1 mHz to 10 MHz, where the use of ultra-low frequencies helps clarify the analysis of the imaginary impedance dispersion. It is shown that the low frequency dispersion described in the literature is the tail of a relaxation peak located at f ≅ 20 mHz. This ultra-low frequency dispersion peak is analyzed with a Cole-Cole impedance element, being associated with the electric double layer at the metal-electrolyte interface. Quantitative information can be extracted for the double layer, including its thickness (∼1 nm) and electrical resistivity (∼50 GΩm). Instituto de Física de São Carlos USP Faculdade de Ciências e Tecnologia UNESP Faculdade de Ciências e Tecnologia UNESP