UV-Ozone reactor with modified high pressure mercury vapor lamp for surface treatment of transparent conductive oxides used in electroluminescent polymeric devices

An UV-Ozone reactor was developed with an ignition tube extracted into HID mercury lamp used to irradiation on zinc oxide (ZnO) and fluorinated tin oxide (FTO) films for PLEDs devices. Different exposures times were used. In contact angle measurements revealed better results for ZnO and FTO by 15 and 5 min, respectively. In Diffuse Reflectance Infra-red Fourier Transformed (DRIFT) spectroscopy allowed the observation of water, hydrocarbon and carbon dioxide adsorbed on the untreated TCO surfaces. After the UV-Ozone treatment the contaminants were significantly reduced or eliminated and the PLEDs devices decreased threshold voltages in comparison with respectively untreated TCOs

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Este trabalho teve como objetivo o desenvolvimento de um conjunto de processos para a fabricação de células solares de silício para utilização espacial, do tipo convencional. As células solares de silício monocristalino desenvolvidas neste trabalho possuem junção rasa, obtida por difusão de fósforo em substrato tipo-p (com resistividade de 1 ou 10 Ohm.cm), grades de contato de Ti/Pd/Ag e camada antirefletora de dióxido de titânio. Em células de 4cm2 foram obtidas eficiências de conversão de até 13,6% com fator de preenchimento de 0,77 em substratos de 1 Ohm.cm e 13% e 0,76 em substratos de 10 Ohm.cm. Células construídas com substratos de 10 Ohm.cm apresentaram melhor tolerância à danos de radiação que as de 1 Ohm.cm. São analisadas as influências da camada antirefletora, resistividade de substrato, geometria e técnicas de deposição da grade de contatos no desempenho elétrico das célulasThe objective of this work was the study and the development of techniques for the fabrication of silicon solar cells, of conventional type, for space applications. The single-crystal silicon solar cells were fabricated on p-type substrates of 1 and 10 Ohm.cm resistivities by thermal diffusion of phosphorus from liquid source. The anti-reflective coatings were made from titanium dioxide obtained by reactive sputtering of a titanium target. A triple titanium-palladium-silver layer was utilized to prepare the contacts. Conversion efficiencies of up to 13.6% and fill factors of 0.77 were obtained in cells fabricated on 1 Ohm.cm substrates and efficiencies of 13% and fill factor of 0.76 were obtained in cells fabricated in 10 Ohm.cm substrates. Better radiation damage tolerance was observed in cells with 10 Ohm.cm substrates when compared with 1 Ohm.cm substrate cells. The inf1uences of the anti-reflective coatings, substrate resistivities, and contact grid geometry and grid deposition techniques on cell performance are analyze

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Este trabalho teve como objetivo o desenvolvimento de um conjunto de processos para a fabricação de células solares de silício para utilização espacial, do tipo convencional. As células solares de silício monocristalino desenvolvidas neste trabalho possuem junção rasa, obtida por difusão de fósforo em substrato tipo-p (com resistividade de 1 ou 10 Ohm.cm), grades de contato de Ti/Pd/Ag e camada antirefletora de dióxido de titânio. Em células de 4cm2 foram obtidas eficiências de conversão de até 13,6% com fator de preenchimento de 0,77 em substratos de 1 Ohm.cm e 13% e 0,76 em substratos de 10 Ohm.cm. Células construídas com substratos de 10 Ohm.cm apresentaram melhor tolerância à danos de radiação que as de 1 Ohm.cm. São analisadas as influências da camada antirefletora, resistividade de substrato, geometria e técnicas de deposição da grade de contatos no desempenho elétrico das célulasThe objective of this work was the study and the development of techniques for the fabrication of silicon solar cells, of conventional type, for space applications. The single-crystal silicon solar cells were fabricated on p-type substrates of 1 and 10 Ohm.cm resistivities by thermal diffusion of phosphorus from liquid source. The anti-reflective coatings were made from titanium dioxide obtained by reactive sputtering of a titanium target. A triple titanium-palladium-silver layer was utilized to prepare the contacts. Conversion efficiencies of up to 13.6% and fill factors of 0.77 were obtained in cells fabricated on 1 Ohm.cm substrates and efficiencies of 13% and fill factor of 0.76 were obtained in cells fabricated in 10 Ohm.cm substrates. Better radiation damage tolerance was observed in cells with 10 Ohm.cm substrates when compared with 1 Ohm.cm substrate cells. The inf1uences of the anti-reflective coatings, substrate resistivities, and contact grid geometry and grid deposition techniques on cell performance are analyze

A Comparative Study on the Optimization of a Ternary P3HT:PCBM:Pentacene Active Layer in Bulk Heterojunction Organic Solar Cells

This work shows a comparative and processing optimization study of the recent ternary bulk heterojunction (BHJ) of P3HT: PCBM:pentacene (1:0.9:0.1 wt. ratio) against the well-known active layer of poly(3-hexylthiophene) (P3HT) blended to phenyl C61 butyric acid methyl ester (PCBM) (1:1 wt. ratio). Initially, monochlorobenzene (MCB) was compared and later replaced by dichlorobenzene (DCB) as active layer solvent. The following optimization step related to thermal annealing effects on solar cell power conversion efficiency (PCE) and fill-factor (FF). Ternary junction slow drying at room temperature without a postproduction thermal treatment proved to be the most suitable to improve BHJ morphology at nanoscale. Finally, ternary composite mass concentration ranged from 20 to 60 mg/ml in DCB to achieve an efficiency near 3% at 40 mg/ml. An observed improvement of at least 15% in photovoltaic efficiency and a practically constant open-circuit voltage (i.e., just 1.2% variation) compared to the already-established P3HT:PCBM blend corroborates the role of pentacene in the active layer to balance mobility from both charge carrier types

Aquaregia and Oxygen Plasma Treatments on Fluorinated Tin Oxide for Assembly of PLEDs Devices Using OC1C10-PPV as Emissive Polymer

In this work were carried out treatments with oxygen plasma and aquaregia on fluorinated tin oxide (FTO) films varying the treatment times. After treatments, the samples were analyzed by techniques measurements: sheet resistance, thickness, Hall effect, transmittance and superficial roughness. Devices using FTO/PEDOT:PSS/OC1C10-PPV/Al were assembled. In this experiment some variations were observed by sheet resistance and thickness and Hall effect measurements indicated most elevated carriers concentration and resistivity for aquaregia than that oxygen plasma. The roughness was elevated for the first minutes with treatment by aquaregia too. In the I-V curves the aquaregia devices presented the lowest threshold voltage for 30 minutes and devices treated by oxygen plasma presented a behavior most resistivity different of typical curves for PLEDs devices

Solvent-Resistant Polymeric Sensors for Adulteration Detection in Liquid Fuels

Polymeric sensors with improved resistance to organic solvents were produced via the layer-by-layer thin film deposition followed by chemical cross-linking. According to UV-vis spectroscopy, the mass loss of polyaniline/poly(vinyl alcohol) and polyaniline/novolac-type resin based films deposited onto glass slides was less than 20% when they were submitted to successive immersions (up to 3,000 immersion cycles) into commercially available ethanol and gasoline fuel samples. Polyallylamine hydrochloride/nickel tetrasulfonated phthalocyanine films presented similar stability. The electrical responses assessed by impedance spectroscopy of films deposited onto Au-interdigitated microelectrodes were relatively unaffected after continuous or cyclic immersions into both fuels. After these studies, an array including these polymeric sensors was employed to detect adulteration in ethanol and gasoline samples. After principal component analysis, it was possible to conclude that the proposed sensor array is capable to discriminate with remarkable reproducibility ethanol samples containing different amounts of water or else gasoline samples containing different amounts of ethanol. In both examples, more than 90% of data variance was retained in the first principal component. For each type of sample, ethanol and gasoline, it was found a linear correlation between one of the principal components and the sample's composition. These findings allow one to conclude that these films present great potential for the development of reliable and low-cost sensors for fuel analysis in liquid phase.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [Proc. 07/00636-1]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [Proc 485857/2007-3]EMBRAPA Agronano NetworkEMBRAPA Agronano Networ

Adapting the GACT-X Aligner to Accelerate Minimap2 in an FPGA Cloud Instance

In genomic analysis, long reads are an emerging type of data processed by assembly algorithms to recover the complete genome sample. They are, on average, one or two orders of magnitude longer than short reads from the previous generation, which provides important advantages in information quality. However, longer sequences bring new challenges to computer processing, undermining the performance of assembly algorithms developed for short reads. This issue is amplified by the exponential growth of genetic data generation and by the slowdown of transistor technology progress, illustrated by Moore’s Law. Minimap2 is the current state-of-the-art long-read assembler and takes dozens of CPU hours to assemble a human genome with clinical standard coverage. One of its bottlenecks, the alignment stage, has not been successfully accelerated on FPGAs in the literature. GACT-X is an alignment algorithm developed for FPGA implementation, suitable for any size input sequence. In this work, GACT-X was adapted to work as the aligner of Minimap2, and these are integrated and implemented in an FPGA cloud platform. The measurements for accuracy and speed-up are presented for three different datasets in different combinations of numbers of kernels and threads. The integrated solution’s performance limitations due to data transfer are also analyzed and discussed