In this paper, we present an ultraflexible tactile sensor, in a piezo-eletricoxide-semiconductor FET configuration, composed by a poly[vinylidenefluoride-co-trifluoroethylene] capacitor with an embedded readout circuitry, based on nMOS polysilicon electronics, integrated directly on polyimide. The ultraflexible device is designed according to an extended gate configuration. The sensor exhibits enhanced piezoelectric properties, thanks to the optimization of the poling procedure (with electric field up to 3 MV/cm), reaching a final piezoelectric coefficient d ₃₃ of 47 pC/N. The device has been electromechanically tested by applying perpendicular forces with a minishaker. The tactile sensor, biased in a common-source arrangement, shows a linear response to increasing sinusoidal stimuli (up to 2 N) and increasing operating frequencies (up to 1200 Hz), obtaining a response up to 430 mV/N at 200 Hz for the sensor with the highest value of d ₃₃ . The sensor performances were also tested after several cycles of controlled bending in different amount of humidity with the intent to investigate the device behavior in real conditions.

A conducting composite prepared by dispersing multi-walled carbon nanotubes (MWCNTs) into a host matrix consisting of Nafion, electrochemically doped with copper, has been prepared, characterized and used to modify one of the gold electrodes of simply designed electrochemical cells having copier grade transparency sheets as substrates. Electrical measurements performed in deionized water show that the Au/Nafion/Au-MWCNTs–Nafion:Cu cells can be successfully used in order to detect the presence of p-aminophenol (PAP) in water, without the need for any supporting electrolyte. The intensity of the redox peaks arising when PAP is added to deionized water is found to be linearly related to the analyte in the range from 0.2 to 1.6 µM, with a detection limit of 90 nM and a sensitivity of 7 µA·(µM⁻¹)·cm⁻².

The Internet of Things (IoT) is gaining more and more popularity and it is establishing itself in all areas, from industry to everyday life. Given its pervasiveness and considering the problems that afflict today’s world, that must be carefully monitored and addressed to guarantee a future for the new generations, the sustainability of technological solutions must be a focal point in the activities of researchers in the field. Many of these solutions are based on flexible, printed or wearable electronics. The choice of materials therefore becomes fundamental, just as it is crucial to provide the necessary power supply in a green way. In this paper we want to analyze the state of the art of flexible electronics for the IoT, paying particular attention to the issue of sustainability. Furthermore, considerations will be made on how the skills required for the designers of such flexible circuits, the features required to the new design tools and the characterization of electronic circuits are changing.

Low frequency noise measurements are among the most sensitive tools for the investigation of the quality and of the reliability of semiconductor devices. The sensitivity that can be obtained depends on the background noise of the low noise preamplifier coupled to the device under test (DUT) that, at very low frequencies, is dominated by flicker noise. The low frequency noise produced by the DUT, on the other end, is very often the most interesting signal to be detected and analyzed. In this work we propose a very simple topology for the realization of a general purpose low noise preamplifier whose noise performances, at very low frequencies (below 10 Hz), are significantly better than those that can be obtained by the most popular commercial instrumentation. Indeed, a gain of 80 dB with a pass band extending from a few tens of mHz up to a few kHz with an equivalent input voltage noise as low as 14 nV/√Hz (100 mHz), 1.4 nV/√Hz (1 Hz), 1.0 nV/√Hz (10 Hz), and 0.8 nV/√Hz (1 kHz) are consistently obtained by using quite standard electronic components and with no need for trimming and/or calibration steps. Moreover, the junction field-effect transistor input stage of the amplifier is characterized by an equivalent input current noise below 4 fA/√Hz in the entire bandwidth, resulting in negligible background noise degradation for DUT impedances in excess of 100 kΩ.

Focusing on the interplay between interface chemistry, electrochemistry, and integrated electronics, we show a novel low-cost and flexible biosensing platform for continuous glucose monitoring. The amperometric biosensing system features a planar three-electrode structure on a plastic substrate, and a wireless NFC-powered electronic system performing sensor analog front-end (AFE), A/D conversion, digital control, and display tasks. The working electrode is made of electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) film onto an Au/PET electrode followed by immobilization of cross-linked glucose oxidase by glutaraldehyde. The advantages offered by such a device, including low-cost materials and instrumentation as well as the good sensitivity of 9.24 μA/(mM · cm2) are promising tools for point-of-care monitoring. It is demonstrated that the devices are good candidates for the development of advanced sensing approaches based on the investigation of the noise produced during operation (Fluctuation Enhanced Sensing).