All-printed smart label with integrated humidity sensors and power supply

Sensing smart labels are an essential component of the Internet of Things (IoT) to provide identification and data. However, the widespread use of these labels into functional devices requires easy integration and power supply. Herein, a smart label is presented with integrated humidity sensor and printed battery. The smart label is composed by detection, communication, control, and energy subsystems. It is based on a screen printed RLC circuit and a printed humidity sensor with electrical linear response. The printed battery based on lithium iron phosphate as an active cathode material is fabricated with six single cells connected in series, leading to approximate to 100 mAh g(-1). The printed humidity sensor has a linear response with a sensitivity of 0.004/% relative humidity (RH). Thus, it demonstrates the development of fully printed smart labels, improving integration into a variety of applications.The authors thank the Fundacao para a Ciencia e Tecnologia (FCT) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2020, UID/EEA/04436/2020, and UID/QUI/0686/2020 and project no. PTDC/FIS-MAC/28157/2017. The authors also thank the FCT for financial support under grants SFRH/BD/131729/2017 (N.P.) and SFRH/BPD/112547/2015 (C.M.C.). Financial support from the Basque Government under the ELKARTEK, HAZITEK, and PIBA (PIBA-2018-06) programs was also acknowledged

Design and fabrication of printed human skin model equivalent circuit: a tool for testing biomedical electrodes without human trials

Within the efforts of developing a new generation of biomedical electrodes with embedded switching logics, the present work focuses on developing safe and simple procedures for testing these novel systems. An all-printed testbed for automated validation of multi-pad systems is presented based on a Human model equivalent circuit (HMEC), a device that, when connected to the electrical stimulation system, mirrors the electrical behavior of electrodes and their specific interface material as if they are placed on a human subject. In the case of transcutaneous electrical stimulation, after a simulation of the different components of the system to optimize printed component characteristics, the fabricated testbed is composed of five flexible screen-printed layers of different materials (conductors and dielectrics) on flexible PET substrate. Electronic components have been developed and integrated, including capacitors and resistances with the defined HMEC characteristic values, matching the average experimental data acquired from human subjects. Thus, an all printed flexible HMEC is provided allowing the suitable evaluation and optimization of skin stimulation devices, reducing the need for tests on human subjects during developing technological stages.We acknowledge the receipt of funding from the European Union’s Horizon 2020 Programme for Research, ICT-02-2018 – Flexible and Wearable Electronics, Grant agreement no. 824339 – WEARPLEX. The authors thank the FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/FIS/04650/2020. Vitor Correia thanks FCT for the junior researcher contract (DL57 / 2016) and within the R&D Units Project Scope: UIDB/00319/2020. Financial support from the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Departments under the Elkartek, Hazitek and PIBA (PIBA-2018-06) programs, respectively, area also acknowledged. The authors thank for technical and human support provided by SGIker (UPV/EHU/ERDF)

Solution processing of piezoelectric unconventional structures

Organic piezoelectric materials stand out compared to ceramic materials due to their lightweight, flexibility, chemical and mechanical resistance and are applied in an increasing number of applications, from sensors and actuators, energy harvesting and storage, biomedical to environmental areas. The present chapter focus on organic piezoelectric materials types as well as on the description of the processing and applications of unconventional structures based on those materials. It is shown that these materials can be obtained in different morphologies, including films, membranes, spheres, fibres, patterning or printed by additivr manufacturing technologies. Therefore, organic piezoelectric materials represent an essential contribution for the next generation of devices with high performance and tailored properties.(undefined