This study presents the design and fabrication of a flexible tactile sensor printed on a cellulose paper substrate using a carbon black (CB) – filled polyvinyl alcohol (PVA) polymer matrix as ink material. In the design, electrodes are obtained by screen printing of CB/PVA composite on dielectric cellulose paper. The screen-printing method is preferred for fabrication because of its simplicity and low manufacturing cost. The tactile sensor is formed by overlapping two ink-printed sheets. Electrical properties are investigated under compressive and tensile strains. The results indicate that the tactile sensor configuration and materials can be used for piezoresistive, capacitive, and also impedance sensors. The same tactile sensor structure is also examined using a commercial carbon-based ink for performance comparison. The comparative study indicates that CB/PVA ink screen-printed on paper demonstrates superior sensitivity for capacitive sensing with low hysteresis, as well as low response and recovery times. The piezoresistive-sensing properties of CB/PVA on cellulose paper show a gauge factor (GF) of 10.68, which is also very promising when conventional metal strain gauges are considered. CB/PVA screen-printed on cellulose paper features impedance-sensing properties and is also sensitive to the measurement frequency. Therefore, the response type of the sensor can be altered with the frequency.

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With advances in electronics, the concept of flexible electronics has left traditional designs behind. Many concepts, such as sensors, transistors, soft robotics, data, and energy storage devices have begun to find more widespread and flexible areas of use. From this point of view, using environmentally friendly, abundant, and renewable natural materials that reduce carbon emissions in the production and disposal of these components is the first step toward the concept of sustainable flexible electronics. This review deals with the integration of sustainable natural materials obtained from plant, animal, and bacterial sources into sensors, displays, data storage, power generation, and soft robotic systems, with appropriate examples compiled from the last ten years. In addition, limitations in the use of sustainable materials as flexible electronic components and their potential for use in innovative electronic applications in the future are foreseen.

Back Cover: The illustration underlines the renewable raw materials that can be obtained from nature in the technological achievements Cem Bayram and co‐workers have gained in their laboratory studies, and showcase in article number 2100978. It is hoped that the delineation of the bridge between flexible electronics and sustainable biomass depicts the importance of this special issue.

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