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The global overabundance of electronic waste and ever‐increasing concerns regarding the energy‐and material‐intensive manufacturing processes associated with traditional electronics are driving the development of solution‐processed, degradable electronics. Of note, the industry‐dominating prevalence of harmful lead‐based materials in sensing and actuating devices drives the push for more eco‐friendly solution‐processed piezoelectric systems. Yet current ecofriendly multi‐material printing processes are limited by both the conventional challenges of multilayer processes as well as the low‐temperature thermal constraints of biodegradable materials. Herein, a novel approach for fabricating fully printed, sustainable piezoelectric transducers on paper substrates is presented. Low‐temperature screen‐printing processes are used to integrate non‐toxic KNbO3 layers with degradable carbon‐ or zinc‐based conductive inks into devices. The influence of electrode material on device characteristics is assessed, with effective piezoelectric coefficients reported as high as 4.6 pC N−1 and 5.1 pC N−1 for devices with carbon and zinc electrodes respectively. The potential of the developed technology is then demonstrated through the first‐ever instance of fully printed piezoelectric force sensors and acoustic speakers comprised entirely of green materials. By demonstrating entirely printable green piezoelectric devices compatible with various electrode materials, this work serves as a step towards developing more complex sustainable piezoelectric technologies in the future. [ABSTRACT FROM AUTHOR]

A fully printed piezoelectric based touch sensor device has been successfully fabricated on flexible polyethylene terephthalate (PET) and paper substrates using screen printing technique. The device, consisting of a 4 × 4 array of printed sensors and interconnect lines, was fabricated using silver (Ag) ink. Screen printed polyvinylidene fluoride (PVDF), as a piezoelectric layer, was sandwiched between the printed Ag top and bottom electrode metallization layers. A linear relationship between the sensor response and varying applied forces to the device was obtained through finite element analysis (FEA) method simulation. X-ray diffraction (XRD) analysis was performed to verify the formation of the β-phase crystals in the PVDF layer during the curing process. The effective polarization of the printed piezoelectric layer was analyzed using capacitance-voltage analysis. A sensitivity of 1.2 V/N and 0.3 V/N, with correlation coefficient of 0.9954 and 0.9859, was obtained for the PET and paper based printed touch sensors, respectively. The piezoelectric-voltage analysis demonstrated that the printed sensors can be used for both touch and force based applications. [ABSTRACT FROM AUTHOR]

In this work, the fabrication of Rochelle salt based piezoelectric structures is illustrated. Structures composed of paper and Rochelle salt are easily manufactured using simple processes. Both manufacturing and the material itself are environmental friendly. Additionally Rochelle salt is biocompatible. In the paradigm of a cleaner piezoelectric technology, the fabrication of active sensing or actuating devices is developed. Thus processing method, material and piezoelectric properties have been studied: (1) pure crystals are used as acoustic actuator, (2) properties of paper impregnated with Rochelle salt are detailed, (3) charge generation is demonstrated on the impregnated material. Actuating and sensing devices are reported in order to highlight the potential of this green piezoelectric material. [ABSTRACT FROM AUTHOR]