Flexible devices serve as important intelligent interfaces in various applications involving health monitoring, biomedical therapies, and human–machine interfacing. To address the concern of electronic waste caused by the increasing usage of electronic devices based on synthetic polymers, bio‐origin materials that possess environmental benignity as well as sustainability offer new opportunities for constructing flexible electronic devices with higher safety and environmental adaptivity. Herein, the bio‐source and unique molecular structures of various types of natural bio‐origin materials are briefly introduced. Their properties and processing technologies are systematically summarized. Then, the recent progress of these materials for constructing emerging intelligent flexible electronic devices including energy harvesters, energy storage devices, and sensors are introduced. Furthermore, the applications of these flexible electronic devices including biomedical implants, artificial e‐skin, and environmental monitoring are summarized. Finally, future challenges and prospects for developing high‐performance bio‐origin material‐based flexible devices are discussed. This review aims to provide a comprehensive and systematic summary of the latest advances in the natural bio‐origin material‐based flexible devices, which is expected to offer inspirations for exploitation of green flexible electronics, bridging the gap in future human–machine–environment interactions.

Gas-solid electrification enabled by a sticky porous elastomer.

Triboelectric nanogenerators (TENGs) are an emerging technology capable of converting the ambient mechanical energy into electricity, promising for complete utilization of the distributed energy to improve the quality of human life. However, realizing material innovation for good trade‐off between the high triboelectric output and environment friendliness remains huge challenge, but it is of great importance for sustainable development of TENGs. Cellulose is a typical natural polymer that promises to address the challenge. Herein, the sustainable TENGs that originate from cellulose and potentially back to the natural world are focused on, realizing on‐spot TENGs. First, the sources, forms, morphologies, structures, and modifications of cellulose are systematically summarized, indicating the commercial and noncommercial cellulose materials’ potential for TENGs’ application. Second, the dominating additive properties of cellulose such as hydrophobicity, self‐cleaning, corrosion resistance, optical transparency, electrical conductivity, and degradability are introduced, which can effectively steer the development of TENGs. Thereafter, the TENGs with tailorable functions enabled by less‐refined cellulose and various physical/chemical modified cellulose are reviewed, as well as plants‐supported on‐spot TENGs with environment adaptivity and transient property, embracing a sustainable future of versatile cellulose to adapt the distributed network of multiscenario TENGs for energy management and information communication.

Triboelectric nanogenerator (TENG) operates on the principle of utilizing contact electrification and electrostatic induction. However, visualization and standardized quantification of surface charges for triboelectric materials remain challenging. Here, we report a surface charge visualization and standardized quantification method using electrostatic surface potential measured by Kevin probe and the iterative regularization strategy. Moreover, a tuning strategy on surface charge is demonstrated based on the corona discharge with a three-electrode design. The long-term stability and dissipation mechanisms of the injected negative or positive charges demonstrate high dependence on deep carrier traps in triboelectric materials. Typically, we achieved a 70-fold enhancement on the output voltage (~135.7 V) for the identical polytetrafluoroethylene (PTFE) based TENG (neg-PTFE/PTFE or posi-PTFE/PTFE triboelectric pair) with stable surface charge density (5% decay after 140 days). The charged PTFE was demonstrated as a robot e-skins for non-contact perception of object geometrics. This work provides valuable tools for surface charge visualization and quantification, giving a new strategy for a deeper understanding of contact electrification.