BARBARA PEREZ GONCALVES SILVA
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Artigo IPEN-doc 30768 Simple and fast preparation of transparent conductive films of silver nanowires obtained by a salt assisted polyol method2024 - SILVA, BARBARA P.G.; SILVA, WILLIAN C. da; SARAIVA, STEFANY R.; OTUBO, LARISSASilver nanowires thin films have gained attention due to their excellent optical and electrical properties, being a potential material to be applied in optoelectronic devices as transparent conductive films, deposited on a substrate in a such way that forms a percolated network. We report the synthesis of silver nanowires with average length of 9.5 ± 0.4 μm and diameter of 75 ± 3 nm by a modified polyol method and fabrication of transparent and conductive thin films using a simple and low-cost technique as drop-casting. Additionally, we examined the influence of the drop-casting method in function of number of deposition cycles on the optical and electrical properties of the films through optical absorption and electrical resistance measurements using the two-point methodology. Increasing the number of silver nanowire deposition layers, the optical transmittance decreased from 97 (for one layer) to 60% (for five layers), and electrical resistance decreased from 940 ± 0.35 Ω for the 2-layer film to 32 ± 0.02 Ω, for the 5-layer film. Due to the electrical conductivity range of the produced silver nanowires films, we suggested their application in low-voltage circuits.Artigo IPEN-doc 29865 Graphene deposited on glass fiber using a non-thermal plasma system2023 - GOMES, PAULO V.R.; BONIFACIO, RAFAEL N.; SILVA, BARBARA P.G.; FERREIRA, JOAO C.; SOUZA, RODRIGO F.B. de; OTUBO, LARISSA; LAZAR, DOLORES R.R.; NETO, ALMIR O.This study reports a bottom-up approach for the conversion of cyclohexane into graphene nanoflakes, which were then deposited onto fiberglass using a non-thermal generator. The composite was characterized using transmission electron microscopy, which revealed the formation of stacked few-layer graphene with a partially disordered structure and a d-spacing of 0.358 nm between the layers. X-ray diffraction confirmed the observations from the TEM images. SEM images showed the agglomeration of carbonaceous material onto the fiberglass, which experienced some delamination due to the synthesis method. Raman spectroscopy indicated that the obtained graphene exhibited a predominance of defects in its structure. Additionally, atomic force microscopy (AFM) analyses revealed the formation of graphene layers with varying levels of porosity.