In this study, a novel approach to the fabrication of a multimodal temperature and force sensor on ultrathin, conformable and flexible substrates is presented. This process involves coupling a charge-modulated organic field-effect transistor (OCMFET) with a pyro/piezoelectric element, namely a commercial film of poly-vinylene difluoride (PVDF). The proposed device is able to respond to both pressure stimuli and temperature variations, demonstrating the feasibility of the approach for the development of low-cost, highly sensitive and conformable multimodal sensors. The overall thickness of the device is 1.2 μm, being thus able to conform to any surface (including the human body), while keeping its electrical performance. Furthermore, it is possible to discriminate between simultaneously applied temperature and pressure stimuli by coupling sensing surfaces made of poled and unpoled spin-coated PVDF-trifluoroethylene (PVDF-TrFE, a PVDF copolymer) with OCMFETs. This demonstrates the possibility of creating multimodal sensors that can be employed for applications in several fields, ranging from robotics to wearable electronics.

A large-area processable ink-jet-printed poly(3-hexylthiophene) electrolyte-gated field-effect transistor, designed for bioelectronic applications, is proven to be stable for one week of continuous operation.

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The increasing diffusion of portable and wearable technologies results in a growing interest in electronic devices having features such as flexibility, lightness-in-weight, transparency and wireless operation. Organic electronics was proposed as a potential candidate to fulfill such needs, in particular targeting pervasive Radio-Frequency (RF) applications. Still, limitations in terms of device performances at RF, particularly severe when large-area and scalable fabrication techniques are employed, have largely precluded the achievement of such an appealing scenario. In this work, the rectification of an electromagnetic wave at 13.56 MHz with a fully inkjet printed polymer diode is demonstrated. The rectifier, a key enabling component of future pervasive wireless systems, is fabricated through scalable large-area methods on plastic. To provide a proof-of-principle demonstration of its future applicability, its adoption in powering a printed integrated polymer circuit is presented. The possibility of harvesting electrical power from RF waves and delivering it to a cheap flexible substrate through a simple printed circuitry paves the way to a plethora of appealing distributed electronic applications. Main text:The rising demand for automatic identification procedures has resulted in an increasing request of portable and pervasive devices, such Radio-Frequency IDentification (RFID) tags, which could be used, for example, to identify everyday objects through electronic serialization codes.In general, RFID devices can be classified depending on the frequency at which they operate.Low-frequency (LF) RFID tags work at 120-145 kHz (LF), high-frequency (HF) tags at 13.56 MHz (HF), and ultra high-frequency (UHF) tags operate at frequencies higher than 860 MHz. [1] Another typical classification of RFID devices is related to the presence or not of a power supply or battery. Active RFID tags contain their own power source giving them the ability to broadcast with a read range of up to 100 meters (far-field communication protocols), so they typically operate in the UHF regime. Passive RFIDs do not have any power supply: all the power required for operating the tag is generated by converting the alternating-current (AC) RF signal received from an antenna into a direct-current (DC) power supply. Thus, the RFID tag usually contains a low resistance antenna and a high-frequency rectifier for AC to DC conversion.Passive RFID tags usually can be read from few cm for proximity readers (near-field communication protocol) and up to 1 m for vicinity readers. Choice of the specific RFID device depends on the target application and it is typically a trade-off among required reading distance, costs and technological constraints. Cost-effective passive tags are more suited for high volume products of limited intrinsic value and the HF range is preferable where bulky coils, such as those required for LF, are not an option, and tag flexibility and ease of