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The contamination on the surface of objects caused by: fungi, microbes, bacteria and viruses (and also coronavirus) can be solved using UV rays and/or ozone gas. For this reason, a UV-Ozone reactor apparatus with low cost was mounted to test two different types of HID (high intensity discharge) lamps: high pressure mercury vapor lamp (HPMVL) and metal halide lamp (MHL), both with nominal power of 400 watts and E-40 (base, screw) were studied as possible method of disinfection. Each lamp used the respective electromagnetic ballasts and both were manufactured by Osram Company. These lamps have two bulb types: the outer bulb which was removed and it is responsible for filtering the ultraviolet wavelengths and the internal bulb (where there is mercury, argon or metal halide confined at high pressure) that is the main source of ultraviolet rays. The complete apparatus was assembled using: aluminum reflector (used as a chamber), two microcomputer fans and a wooden base covered by an aluminum foil. A rubber strip was placed at the edge of the reflector for better adhesion on the aluminum foil (for better confinement ozone gas). The ozone concentration inside the reactor was measured with a monitor, the temperatures were measured near lamps with a thermocouple and a spectroradiometer with optical fiber was used to obtain the wavelengths. The results revealed to the elapsed time of 2 minutes a maximum peak of ozone concentration of 23 ppm for LVMAP, while the MHL presented 4.5 ppm only. The temperature obtained by HPMVL was lower with 31.5 ºC, while the MHL presented 48.0 ºC. The HPMVL presented higher amount of wavelengths at the ranges: UV-A, UV-B and UV-C, while the MHL presented only UV-A. For these reasons, it is suggested to be most promissory the use of HPMVL to combat the coronavirus and other pathogenic microorganisms.

This exploratory study was carried out with the objective to know the optical behavior of light-emitting diode (LED) lamps used and the temperature reached by electronic components that compose the driver (electronic circuit situated inside the body LED lamp) responsible to convert electrical alternating current from power line to direct current to operate the LED devices. Then, two different experiments were carried out with LED lamps. In the first experiment, 131 LED lamps used were chosen randomly and bought from household appliances store (bargain market product) presenting different nominal powers, 8, 10, 12 and 15 watts. All LED lamps were polarized at the power line at 127 V and revealed different optical behaviors, such as: not turn-on; flashing light (as strobe effect); flashing light (as strobe effect) with high intensity (more intense than normal); flashing light (as strobe effect) with low intensity (less intense than normal); fast turnon and turn-off only; and turn-on with low intensity of light (less intense than normal). The hypothesis for these behaviors can be attributed by three different behaviors: in lamps not turn-on, this failure can be attributed for dark spots that are created on the surface of LED device. In these lamps, all LED devices are electrically connected in serial. When a LED is inoperative, the electrical current is interrupted for all LED devices; damage to the electronic components caused by internal high temperature confined inside the lamp body during the operation causing electrical oscillations, as observed from different behaviors from flashing light, flashing light with high intensity, flashing light with low intensity and fast turn-on and turn-off only; swelling of the electrolytic capacitors causing low energy storage and varying the electrical current flow, the electrical current for other electronic components altered the normal optical behavior of the LED lamps. In the second experiment, the temperatures of electronic components located in driver were obtained out of body lamp revealing: from 33 (lowest temperature attributed to inductor) to 52.5ºC (highest temperature attributed to electrolytic capacitor). These temperature values represent the ideal or normal condition of operation for electronic components, but, when they are operating inside the lamp body, the found temperature values increased considerably. This characteristic can be better evidenced by strong color change (caused by accumulative temperature during the elapsed days used) on the printed circuit board used in the driver.

In this work, circular economy was investigated for commercial indium tin oxide (ITO) thin films deposited on glass substrates obtained from degraded organic light-emitting diodes (OLED). These devices were assembled and polarized at laboratory in a previous work. For each substrate, with geometry 2.5 × 2.5 cm, four OLEDs with active area of 3 × 3 mm were set up. These OLED devices were assembled with ITO as the electrode anode and successive depositions of other materials (layer-by-layer), to form the complete structure. To obtain the recovered ITO, all layers were removed from the samples containing the OLEDs previously mounted, remaining only the ITO thin films, that were cleaned with commercial product together with the received ITO/glass samples. Both samples were compared using some techniques, such as: colorimetry, electrical resistance, and Raman spectroscopy. A methodology with light-emitting diode (LED) device polarized emitting light crossing the ITO thin films was used, and the luminance with chromaticity coordinates was obtained, revealing the good transparency of the thin films. Electrical resistance of recovered ITO revealed five higher orders of magnitude in comparison to the one of received ITO. This fact can be tributed to a poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) layer, causing corrosion of the ITO thin films during the assembly of OLEDs or loss of the field lines created during the electrical measurements by probes of four-point probe. Raman spectroscopy did not show satisfactory results in the chemical composition analyses of the samples, but it indicated good cleaning process of the samples before the analyses.

In this study, optical and lifetime analyses of commercial light-emitting diode (LED) lamps were carried out with the objective to better understand these characteristics. Lamps of different manufacturers and powers were used: Ourolux of 9 watts, Kian of 9 watts, Black+Decker of 9 watts, FLC of 8 watts, Galaxy of 7 watts and Brilia of 7 watts. These LED lamps remained on by 24 hours/day for 4,291.16 hours. Illuminance measurements were analyzed once a week by each lamp inside the integrating sphere with a sensor of lux meter coupled. Results showed decrease of illuminance by elapsed time, due to the degradation. Results of the illuminance obtained between the initial moment of the experiment and the final one were calculated, revealing degradation of 19% to Ourolux, 20% to FLC, 26% to Black+Decker, 28% to Kian, 29% to Galaxy and 33% to Brilia. This study suggests that the diffusers can have different transmittance values interfering on the illuminance, since the FLC LED lamp presented illuminance with highest values than the other LED lamps tested with similar electrical and optical characteristics. This experiment showed that the nominal power of the LED lamp has no direct relation to the illuminance and, comparing the lifetime, the LED lamp manufactured by Black+Decker was the only one to reach 5,521 hours, that is a lifetime much shorter than the one described at the packages (25,000 hours) for all LED lamps tested

In this work, organic light-emitting diode (OLED) devices were mounted using the structure: glass (as substrate)/indium tin oxide (ITO) (as anode)/poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) (as hole transport layer)/poly[9,9-dioctifluorene-alt-bis-tienilene(benzotiadiazole)] (PFTB) (as luminescent material)/aluminum-doped zinc oxide (AZO) (as electron transport layer)/aluminum (as cathode). The PFTB was synthetized at laboratory and diluted in different organic solvents as chloroform and trichlorobenzene. The I-V curves of OLED devices showed that the trichlorobenzene used to dillute the PFTB improved the performance for OLED devices promoting the highest electrical current of ≈50 mA and the lowest range of thresold voltage from ≈2.5 to 5 volts, while the device OLEDs mounted with PFTB dilutted in chloroform presented maximum electrical current of ≈23 mA and range of thresold voltage from ≈5 to 8 volts. A hypothesis that explain these results can be attributed to the boiling point of the organic solvent of trichlorobenzene (≈214.4ºC) to be higher than the one of the chloroform (≈61.1ºC), favoring better rearrangement of the polymer chains of PFTB and interfaces between thin films PFTB/PEDOT:PSS and PFTB/AZO improving the injection of charges (holes and electrons) inside the OLEDs devices.

A simple method with low cost of encapsulation for organic light emitting diode (OLED) devices mounted at laboratory was proposed to obtain considerable increase of the lifetime. In this study, it was used a capsule formed by: glass slide as substrate, a layer of polyvinyl acetate glue diluted in methyl alcohol, a layer of calcium oxide as secant and epoxy placed at the edges of capsule. The performance of this capsule was analyzed using a thin film of polymer semiconductor called as PEDOT:PSS, that is sensitive to moisture and oxygen from atmospheric air. The PEDOT:PSS thin layer was deposited between anode and cathode electrodes using commercial indium tin oxide (ITO) thin film deposited on glass substrate. The capsule was placed covering completely the PEDOT:PSS thin film, and the electrical resistance was measured by elapsed days. This result revealed lowest electrical resistance compared with other methods, showing also good performance as encapsulation process.

In this work, a spinner apparatus was mounted with some characteristics, as: low cost, easy operation, compact size, easy adaptation into the little glove box systems, no vacuum pump and low maintenance. Firstly, three different fans wereanalyzed to be used in thespinner apparatus. Then, the Arduino electronic circuit was analyzed and programmed to control the rotation speed using a pulse width modulation (PWM) and steps of acceleration with the signal distortion (caused by pulse width modulation) of thefan intern tachometer. After, the interface between the user and spinner apparatus was performed with information about: navigation through the menus; input of process parameters as rotation speed; rotation time and calibration menu. Successive depositions of organic thin films to assembly of OLED deviceswere used with the spinner apparatus. The experiment compared ITO (indium tin oxide) thin filmanodes with sheet resistances of 8 and 12 ?/? supplied by different manufacturersin the structure of the OLEDs.I-V curves of OLED devices showed that the ITO/glass of 12 ?/? presented better results with low variabilityand highest current values. All OLED devices presented some luminance showing the efficiency of spinner apparatus.

A glass flask obtained of pickled food was developed as bulb with intern vacuum to tests of encapsulation method for electroluminescent devices. At the lid of glass flask were adapted: two (02) metallic valves to vacuum or insert inert gas, one (01) pressure gauge (with high or low pressures) and one (01) printed circuit board with copper stripes for electrical connections, all these components were sealed with epoxy. In the first investigation was carried out intern vacuum at 76 cm.Hg observing the possible variation of intern pressure by elapsed time (for seven days). In the second investigation were used four (04) incandescent lamps (of 12 V and 10 W) without outer bulb to obtain the tungsten filaments that were polarized under vacuum atmosphere at different situations. After seven (07) days, only an insignificant increase of intern pressure was observed. The bulb with intern pressure at 76 cm.Hg promoted to the tungsten filament at least forty (40) polarizations, while outside the bulb (at room pressure) were obtained only two (02) polarizations with significant degradation. A layer of WO2 (tungsten oxide) with greenish yellow color formed on the surface of tungsten filament and it was obtained by microscopies and confirmed by EDXS measurement.

Dispositivos OLEDs (diodos orgânicos emissores de luz) foram montados com copolimero PFTB (ou poli[9,9-dioctifluoreno-altbis-tienileno (benzotiadiazol)]) como camada emissora de luz. Este copolimero foi sintetizado em laboratorio por reacao de acoplamento de Suzuki e apresentou rendimento de 80% com pico de fluorescencia maxima em ± 710 nm. Nas arquiteturas dos dispositivos OLEDs foram utilizadas camadas de AZO comercial:1-ITO/PEDOT:PSS/PFTB/Al; 2 ITO/PEDOT: PSS/AZO/PFTB/ Al; e 3 - ITO/PEDOT: PSS/PFTB/AZO/Al, todos os dispositivos nao foram encapsulados. A arquitetura 3 apresentou menor tensao de limiar com 4,5 V e espectros de emissao do OLED polarizado em diferentes tensoes, mostrando que a camada de AZO sobre o copolimero emissor, alem de atuar como camada injetora de eletrons, tambem protege o dispositivo contra a degradacao, aumentando o desempenho.

This work aims the development of a compact spinner to be used inside the glove-box chamber to deposition of polymeric thin films used in the build of OLED devices. Initially, ten fans extracted of microcomputers were tested with commercial multi-voltage power supply. Four fans were selected based on the standard deviation of speed. A variable power supply was also built in order to get a more detailed response in terms of electrical current and speed in function of applied voltage. The fan that showed less variation of speed with applied voltage was selected for deposition tests using polymeric photoresist solution on the ITO (indium tin oxide) coated glass. This polymer was deposited by spin-coating at different speeds: 1000, 2000, 3000 and 4000 rpm and dried for the thicknesses measurement revealing good uniformity. Finally, three OLED devices were assembled with 2000 and 3000 rpm and the layers were dried under the same conditions. In the structure of the devices were used the materials deposited layer-by-layer:glass/ITO/PEDOT:PSS/ Polyfluorene (PFpf)/Al. The OLED devices revealed blue light electroluminescence. The I-V curves showed better performance for OLED devices mounted at 2000 rpm with higher current density and similar appearance to the diode curve.