EMA 2017

28/04/2017 16:13

No início deste ano o LAMATE participou do Electronic Materials and Applications 2017, em Orlando nos Estados Unidos, realizado pela The American Ceramic Society. Neste congresso foram apresentados três trabalhos desenvolvidos no laboratório.

Parabéns a todos os envolvidos pela participação.

Todos os resumos do evento podem ser conferidos aqui.

Na sequência temos resumos dos trabalhos apresentados.

Nanostructured ZnO/Graphene xerogels with photosensing properties

I. C. Cezário*1 ; D. Muller2 ; F. R. Moreira1 ; C. R. Rambo1 ; 1. Federal University of Santa Catarina, Brazil; 2. Federal University of Santa Catarina, Brazil

Graphene based nanocomposites with emerging optoelectronic properties have been developed for applications as photodiodes and solar cells. In this work ZnO/graphene nanocomposites were produced in situ with different graphene concentrations through the sol-gel method. Drying in air for 24 h led to a bulk xerogel structure. Electrical characterization was performed by tracing the I-V curves of the nanocomposites in the dark and under different illumination conditions (visible and UV light). Significant current variation, from 10 nA to 10 μA, was observed for the different graphene containing samples depending on the wavelength and light intensity. Moreover the photocurrent increased with graphene content for the same lightning condition. The highest photosensibility was recorded for the nanocomposite with 5 wt.% graphene. The results indicate the potential of the developed ZnO/Graphene nanocomposite in applications like photodiodes, photoresistors and solar cells.

 

Nanostructured ZnO/graphene for hybrid supercapacitor devices

I. C. Cezário*1 ; F. R. Moreira1 ; D. Muller2 ; C. R. Rambo1 ; 1. Federal University of Santa Catarina, Brazil; 2. Federal University of Santa Catarina, Brazil

The development of complementary energy storage devices has been study in the last years. Efforts have been made to satisfy the requirements of electrochemical energy storage, such as supercapacitors, using materials with high cost-benefit relation. Transitions metal oxides, like ZnO, are promising materials for supercapacitors due to their excellent pseudocapacitive properties, fast and reversible redox reactions. Graphene, on the other hand exhibits high electrical conductivity and suitable double layer properties for supercapacitors. In this work, ZnO/graphene nanocomposites were produced by sol-gel process. Graphene was incorporated in situ in different concentrations, from 3 wt.% to 10 wt.%(relative to the precursor, ZnCl2). Supercapacitors were assembled using the nanocomposites as active electrodes and PVA/H3PO4 as gel electrolyte. The device mounted with pure ZnO presented specific capacitance of 19 F/g. Incorporation of graphene provided a double layer capacitance in addition to the pseudocapacitance of the ZnO. The ZnO/3%graphene device presented a capacitance of 423F/g, while the ZnO/5% graphene presented 378F/g. Addition of 10%graphene, however decreased the specific capacitance to 161F/g. The device assembled with ZnO/ 3%graphene presented values of energy density and power density that classify them in the supercapacitor category, delivering a maximum energy density of 2.5Whkg-1 and a maximum power density of 96kWkg-1.

 

Modeling multicomponent circuits in ZnO\graphene nanocomposites: A bottom-up approach

I. C. Cezário*1 ; D. Muller3 ; F. R. Moreira2 ; G. A. de Barros2 ; H. P. Roldán2 ; C. R. Rambo2 ; 1. Federal University of Santa Catarina, Brazil; 2. Federal University of Santa Catarina, Brazil; 3. Federal University of Santa Catarina, Brazil

Nanocircuits are being developed for diverse applications from increasing computer performance to new tools for medicine and especially in nanoeletronics. In this work, bulk ZnO/Graphene nanocomposites were produced through an in situ sol-gel method, followed by controlled drying. The nanostructured gels were electrically characterized through I-V curves under different input conditions and their behavior was modelled using multicomponent circuits where the synthesis parameters, final compositions and working electrodes could be related to the elements of the equivalent integrated circuit. Graphene (50-100 nm) with concentrations in the range of 1-10 wt.% was in situ incorporated into zinc oxide gel precursor during gel synthesis. The nanocomposites were characterized according to the crystalline structure and surface area. Modeling of the electrical behavior of the composite was performed using PSpice software. Results revealed that discrete electronic models could be extracted from the nanocomposites.