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Flexible sensors show great application potential in wearable electronics, human‐computer interaction, medical health, bionic electronic skin and other fields. Compared with rigid sensors, hydrogel‐based devices are more flexible and biocompatible and can easily fit the skin or be implanted into the body, making them more advantageous in the field of flexible electronics. In all designs, polyvinyl alcohol (PVA) series hydrogels exhibit high mechanical strength, excellent sensitivity and fatigue resistance, which make them promising candidates for flexible electronic sensing devices. This paper has reviewed the latest progress of PVA/plant‐based biomass hydrogels in the construction of flexible sensor applications. We first briefly introduced representative plant biomass materials, including sodium alginate, phytic acid, starch, cellulose and lignin, and summarized their unique physical and chemical properties. After that, the design principles and performance indicators of hydrogel sensors are highlighted, and representative examples of PVA/plant‐based biomass hydrogel applications in wearable electronics are illustrated. Finally, the future research is briefly prospected. We hope it can promote the research of novel green flexible sensors based on PVA/biomass hydrogel. [ABSTRACT FROM AUTHOR]

Charge/light-related advancements have greatly pushed the development of modern technology, and the relationship between charge and light is worth exploring. While research into the applications of light and charge flow (photoelectric current) is in full swing, studies on the reaction between light and electrostatic charge have made little progress on rare ways to realize photo-stimulated discharge. Herein, we link electrostatic charge and light using a bridge of intense heat, which is produced from the efficient photothermal conversion of Ti3C2Tx MXene. The in situ photothermal conversion and selective thermally stimulated discharge are successfully combined, then novel light-induced electrostatic lithography can be realized on both polymethyl methacrylate glasses and nanofilms. In this process the surface temperature of Ti3C2Tx film can be as high as 300 °C using 808 nm near-infrared irradiation at a power density of 1.7 W cm−2. The combination of light and electrostatic charge is also successfully applied to electrostatic printing and chemical reactions. [ABSTRACT FROM AUTHOR]

Photothermal conversion behavior has a vital application to disease therapy, water purification, or uncontacted heaters. The fabrication of high-performance photothermal conversion materials especially for near-infrared (NIR) light and microstructures has attracted a great deal of attention. Among numerous substances, MXene as a new type of 2D material with semi-metallic and unique electromagnetic properties presents a broader absorption of light and even a typical plasmonic absorption near the NIR-I area (808 nm), which has made it suitable for photothermal conversion. Here, we propose a facile approach for preparing a Ti 3 C 2 T x /ionic liquid ink with a high photothermal conversion efficiency. The as-prepared ink has showed good wettability of various substrates as well as the high sensitivity of 808 nm NIR light irradiation and a wide range of thermal variation. After packing the ink into a gel pen refill, the flexible thermal chips could be easily obtained just by pen writing on the soft surface with the designed size, which also have become an optimal candidate for the thermal alarm system.