Investigations on printed elastic resistors containing carbon nanotubes

Abstract

This paper presents the results of authors investigations on elaboration of a new thick film composition filled with carbon nanotubes (CNTs). The polymer composition consists of polymer vehicle, which is the solution of organic resin in certain combination of solvents, and functional phase-carbon nanotubes well dispersed in the vehicle. The pastes were applied with screen-printing on several substrates and temperature cured. The properties of obtained layers were characterized. Series of samples were prepared with different amount of CNTs to evaluate electrical properties. Changes in resistance were investigated during periodic mechanical and temperature stresses, realized through cyclical bending and rapid temperature change. Tensometric effect was also investigated. Investigations have proved that polymer composites based on carbon nanotubes exhibit high resilience to stress factors. Resistance change in function of temperature was also investigated to evaluate temperature coefficient of resistance (TCR). All this aspects are important for elastic resistors fabrication in printed electronics microcircuits. Resistance and noise measurements in cryostats have also been involved. 1/f type noise has been observed. Noise intensity, calculated in decade frequency bands, rises significantly with increasing temperature. Activation energies of thermally activated noise sources (TANS) have been revealed using low-frequency noise spectroscopy. Relatively large value of negative TCR has been obtained from resistance versus temperature curve. Calculated dimensionless sensitivity is similar to that observed in cryogenic temperature sensors. However, bulk noise intensity of resistive layer is larger than obtained for lead containing RuO 2 based resistive layers.

Noise sources in polymer thick-film resistors

“…An example plot of such a noise map, obtained for sample ED7100/Cu, is presented in Figure 3(a), revealing TANSs (strips on the graph) with activation energies of 0.32 and 0.23 eV. TANSs have been previously observed in TFRs made of RuO 2 -glass (Kolek et al, 2007), in IrO 2 (Pellegrini et al, 1983), in Bi 2 Ru 2 O 7 (Masoero et al, 1983) and in polymer compositions with carbon nanotubes (Słoma et al, 2011). The spectrum recorded at 77 K is shown in Figure 3(b), confirming that, apart from a dominant 1/f noise component, Lorentzians also exist that are associated with TANSs.…”

“…The high performance of modern processors allows the continuous calculation and recording of high resolution spectra in real time, which makes it possible to build a noise map, i.e. a detailed plot of power spectral density of fluctuating quantity versus frequency and temperature, revealing thermally activated noise sources (TANS) (Kolek et al, 2007;Stadler, 2011;Słoma et al, 2011).…”

“…In 1998, Dziedzic and Kolek (1998) published a report of exhaustive studies on low-frequency noise in thick-film resistors (TFRs), made of polymer compositions with carbon fillers, that were performed at room temperature by means of spectra measurements. Since that time, great progress has been achieved by investigators; it is possible to study fluctuating phenomena in TFRs over a wide range of temperatures, from liquid helium temperature (Kolek et al, 2007;Stadler, 2011;Słoma et al, 2011), up to 700 K (Chen et al, 1982;Pellegrini et al, 1983;Masoero et al, 1983;Stadler et al, 2014). The measurement technique applied by Kolek et al (2007), Stadler (2011), Słoma et al (2011…”

“…Since that time, great progress has been achieved by investigators; it is possible to study fluctuating phenomena in TFRs over a wide range of temperatures, from liquid helium temperature (Kolek et al, 2007;Stadler, 2011;Słoma et al, 2011), up to 700 K (Chen et al, 1982;Pellegrini et al, 1983;Masoero et al, 1983;Stadler et al, 2014). The measurement technique applied by Kolek et al (2007), Stadler (2011), Słoma et al (2011…”

Noise Properties of Graphene-Polymer Thick-Film Resistors

“…Polymer thick-film resistors (PTFRs) have many advantages, among others a wide resistivity range, low processing temperature, low cost. Although they have been used in electronics for many years, they are considered as good candidates for the next generation of functional electronic components, especially due to their flexibility [6,7]. Manufacturing technologies of this material are still in the developing stage.…”