Tomi Kanerva

Application of Wide-Band Material Characterization Methods to Printable Electronics

In this paper, characterization methods are presented with results from test structures printed with varying printing parameters and materials. It is shown that different process parameters affect both physical and electrical material properties and hence high-frequency material characterization is a vital part of the process providing important information for design purposes. The conductivities and loss information of nanoparticle inks and properties of dielectric material are achieved in addition to structural properties. In particular, dc measurement results from 1.1e7 S/m to 3.7e7 S/m and high-frequency attenuation values from 0.5 dB/cm to 2.8 dB/cm (at 10 GHz) are achieved for printed conductors.

Application of wide-band material parameter extraction techniques to printable electronics characterization

Material characterization is an important part of printable electronics design, since material properties depend strongly on the manufacturing process. This paper reviews application of wide-band extraction techniques to printable electronics characterization. The extraction methods are validated using full-wave simulation data with exactly known reference for material parameters. Suitable test structures are evaluated and applied to printable electronics characterization.

Iron Oxide Doped Alumina-Zirconia Nanoparticle Synthesis by Liquid Flame Spray from Metal Organic Precursors

The liquid flame spray (LFS) method was used to make iron oxide doped alumina-zirconia nanoparticles. Nanoparticles were generated using a turbulent, high-temperature (𝑇max∼3000 K) H2-O2 flame. The precursors were aluminium-isopropoxide, zirconium-𝑛-propoxide, and ferrocene in xylene solution. The solution was atomized into micron-sized droplets by high velocity H2 flow and introduced into the flame where nanoparticles were formed. The particle morphology, size, phase, and chemical composition were determined by TEM, XRD, XPS, and N2-adsorption measurements. The collected particulate material consists of micron-sized aggregates with nanosized primary particles. In both doped and undoped samples, tetragonal phase of zirconia was detected in room temperature while alumina was found to be noncrystalline. In the doped powder, Fe was oxidized to Fe2O3. The primary particle size of collected sample was approximately from 6 nm to 40 nm. Doping was observed to increase the specific surface area of the powder from 39 m2/g to 47 m2/g.

Wide-band Electrical Characterization of printable nano-particle copper conductors

Copper nano-particle ink suitable for printing is a promising substitute for silver- or gold-based inks for consumer electronics applications. However, oxidization must be controlled during the manufacturing and sintering processes. In this work conductors created from a copper nano-particle ink are characterized. In order to mitigate oxidation effects, the ink was formulated in inert atmosphere. Sintering is achieved by exposure to a short light pulse, which, due to the short time scales (ms) and added benefit of photoreduction, can be done in air. Wide-band electrical characterization results up to 20 GHz for copper nano-particle conductors are presented. Structural analysis using scanning-electron microscope (SEM) complements the characterization. Based on high-frequency measurements, wide-band material parameter extraction techniques, and modeling-based analysis of measurement results, the conductivity was found to be of the order of 0.7·107 S/m. All loss mechanisms including impurities deposited within the metal, porosity, surface roughness, and variation in structure geometry are attributed to the conductivity. The electrical performance was found almost comparable to that of silver-based inks. Also the average measured direct-current (dc) conductivity 1.37·107 S/m is similar to that of typical nano-metal conductors.

Characterization of catalyst poisoning in biodiesel and conventional diesel fuelled vehicles

Demand for lower and lower emissions in road transportation has promoted the development of more efficient exhaust emission catalysts. On the same time the fight against the impact of transportation on climate change has opened the way for the use of biofuels, e.g. biodiesel. Deactivation of catalytic surfaces is a serious problem in the design of more efficient automotive exhaust catalysts. Deactivation of catalysts can be classified in three types: chemical (e.g. poisoning), mechanical (e.g. fouling) and thermal (e.g. ageing). In the long run these deactivation processes can cause nearly total loss of catalytic activity in the catalyst material. In biodiesel fuelled vehicles these processes can lead to notably different effects in catalyst efficiency compared to those of conventional diesel vehicles [1].