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This work reports the synthesis of Ni(OH) 2 aerogels incorporated in situ with polypyrrole (PPy) for application as electrodes in high-capacity energy storage devices. Ni(OH) 2 gels were prepared by the sol-gel method from NiCl 2 as precursor and propylene oxide as gelling agent in ethanol. Pyrrole monomer was added prior to gelling of the sol and in situ polymerized using ammonium persulfate as oxidant agent. After solvent exchanges from ethanol to acetone, the gels were dried in a CO 2 supercritical point drier. Powdered aerogels were deposited onto both sides of a poly(vinyl alcohol)/H 3 PO 4 film (electrolyte/separator) and the contacts were closed with copper foils, resulting in a complete device. Through cyclic voltammetry and charge/discharge curves, the performance of the supercapacitors was evaluated by the specific capacitance, power and energy densities and series resistance. The specific capacitance was increased by 43% with the incorporation of 0.2 mol/L PPy (276 F/g) and the series resistance obtained decreased by 79% (46.5 X/cm 2), which reflects the enhanced performance and electrochemical properties of Ni(OH) 2 aerogel-based devices incorporated with PPy.

Inkjet printing presents a high potential for cost reduction of electronic devices manufacturing due to the capacity to deposit materials with high precision, less material waste, and large-scale production through the roll-to-roll printing processes. In this work, a nanostructured TiO2 ink was developed using TiO2 aerogel and an alkaline aqueous solution, which resulted in a very stable suspension. A high-intensity ultrasonic mixer was used to fragment and disperse TiO2 aerogels producing suspensions with particles smaller than 200 nm, which are suitable for the inkjet printing process. For the development of the ink, the viscosity and surface tension were adjusted by using glycerol and a surfactant (Triton X-100). The influence of those components on the properties of the ink was evaluated for different concentrations. After formulation of the inks, the printing parameters were adjusted to optimize the process. Films with high surface area and less than 100 nm grain size were successfully produced. Electrical measurements revealed a resistive-like behavior with the sheet resistance increasing with number of printed layers.

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The development of organic materials with photovoltaic properties should enable the production of polymeric solar cells with high conversion efficiency. Due to low production cost and conversion efficiency above 10%, organic solar cells have great potential to compete with inorganic photovoltaic cells. This work proposes the development and integration of ETA (extremely thin absorber) photovoltaic cells, based on titanium oxide films and nanostructured conductive polymer in ceramic tiles, with the purpose of increasing the available area for sunlight capture, normally limited to roofs, expanding it onto the lateral sides of buildings. The nanostructured TiO2 was obtained by sol-gel process from titanium isopropoxide, followed by supercritical CO2 extraction in order to obtain a nanostructured aerogel. The conductive polymer used was the poly-3.4 (ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) synthesized with iron III p-toluene sulfonate as an oxidizing agent. The materials were deposited layer by layer on a Cu electrode mounted on a ceramic tile piece, covered with glass containing a thin conductive layer of indium doped tin oxide (ITO). Transmission electron microscopy (TEM) revealed that the nanostructured titania aerogels exhibit particle sizes in the range of 2-5 nm. Preliminary studies have shown that the developed solar cell show a behavior typical of diodes (characteristic I×V curve) when subjected to different wavelength lamps (fluorescent and UV). Ceramic wall and roof tiles with photovoltaic properties, independently of the conversion efficiency, could serve as auxiliary energy sources to reduce expenses with conventional electricity.