closely relevant to normal bodily functions as well as clinical cues of the progression of various diseases. Thus, their continuous and real-time acquisition with soft on-skin electronics, in a manner that does not disrupt our routine daily activities, will be useful for medical diagnostics, fitness tracking, human-machine interface, athletic training, and many others. During the past decade, soft on-skin electronics have been achieved by employing flexible and stretchable forms of inorganic electronic materials, [1][2][3] intrinsically soft organic electronic materials, [6][7][8][9] or emerging nanomaterials [10][11][12][13] as device components and using elastomers or plastics as substrates. However, one critical scientific challenge is that most materials used for on-skin electronics have limited gas permeability, which blocks sweat gland and constrains perspiration evaporation, resulting in adverse physiological and psychological effects, such as rashes, stuffiness, and/or other inflammatory skin responses, limiting their longterm feasibility. [10] In addition, the device fabrication process of on-skin electronics usually involves e-beam or photolithography, thin-film deposition, etching, and/or other complicated procedures, which are costly and time-consuming, constraining their practical applications.Great progress has been recently achieved to address the aforementioned two challenges. For example, free-standing gold nanomesh conductors were used to develop on-skin electronics with high gas permeability, which can significantly suppress the risks of skin inflammation, but are limited to complex fabrication processes such as electrospinning and vacuum deposition. [10] In another study, a "cut-and-paste" manufacturing method was developed to offer a simple way of fabricating multiparametric on-skin electronic systems. [17] However, the materials used for device fabrication, such as gold and aluminum, have limited gas permeability. Therefore, it is highly desirable to develop a simple and effective approach of making on-skin electronics using highly gas-permeable materials.Introducing porous structures into existing functional materials is a powerful way to tailor their gas permeability as well Soft on-skin electronics have broad applications in human healthcare, humanmachine interface, robotics, and others. However, most current on-skin electronic devices are made of materials with limited gas permeability, which constrain perspiration evaporation, resulting in adverse physiological and psychological effects, limiting their long-term feasibility. In addition, the device fabrication process usually involves e-beam or photolithography, thin-film deposition, etching, and/or other complicated procedures, which are costly and time-consuming, constraining their practical applications. Here, a simple, general, and effective approach for making multifunctional on-skin electronics using porous materials with high-gas permeability, consisting of laserpatterned porous graphene as the sensing components and sugar-templa...

In this paper, we demonstrate that by simple laser induction, commercial polyimide films can be readily transformed into porous graphene for the fabrication of flexible, solid-state supercapacitors. Two different solid-state electrolyte supercapacitors are described, namely vertically stacked graphene supercapacitors and in-plane graphene microsupercapacitors, each with enhanced electrochemical performance, cyclability, and flexibility. Devices with a solid-state polymeric electrolyte exhibit areal capacitance of >9 mF/cm2 at a current density of 0.02 mA/cm2, more than twice that of conventional aqueous electrolytes. Moreover, laser induction on both sides of polyimide sheets enables the fabrication of vertically stacked supercapacitors to multiply its electrochemical performance while preserving device flexibility.

Transparent electronic memory would be useful in integrated transparent electronics. However, achieving such transparency produces limits in material composition, and hence, hinders processing and device performance. Here we present a route to fabricate highly transparent memory using sio x as the active material and indium tin oxide or graphene as the electrodes. The two-terminal, nonvolatile resistive memory can also be configured in crossbar arrays on glass or flexible transparent platforms. The filamentary conduction in silicon channels generated in situ in the sio x maintains the current level as the device size decreases, underscoring their potential for high-density memory applications, and as they are two-terminal based, transitions to three-dimensional memory packages are conceivable. As glass is becoming one of the mainstays of building construction materials, and conductive displays are essential in modern handheld devices, to have increased functionality in form-fitting packages is advantageous.

Two types of graphene oxide fibers are spun from high concentration aqueous dopes. Fibers extruded from large flake graphene oxide dope without drawing show unconventional 100% knot efficiency. Fibers spun from small sized graphene oxide dope with stable and continuous drawing yield in good intrinsic alignment with a record high tensile modulus of 47 GPa.

In addition to mechanical compliance, achieving the full potential of on-skin electronics needs the introduction of other features. For example, substantial progress has been achieved in creating biodegradable, self-healing, or breathable, on-skin electronics. However, the research of making on-skin electronics with passive-cooling capabilities, which can reduce energy consumption and improve user comfort, is still rare. Herein, we report the development of multifunctional on-skin electronics, which can passively cool human bodies without needing any energy consumption. This property is inherited from multiscale porous polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) supporting substrates. The multiscale pores of SEBS substrates, with characteristic sizes ranging from around 0.2 to 7 µm, can effectively backscatter sunlight to minimize heat absorption but are too small to reflect human-body midinfrared radiation to retain heat dissipation, thereby delivering around 6 °C cooling effects under a solar intensity of 840 W⋅m−2. Other desired properties, rooted in multiscale porous SEBS substrates, include high breathability and outstanding waterproofing. The proof-of-concept bioelectronic devices include electrophysiological sensors, temperature sensors, hydration sensors, pressure sensors, and electrical stimulators, which are made via spray printing of silver nanowires on multiscale porous SEBS substrates. The devices show comparable electrical performances with conventional, rigid, nonporous ones. Also, their applications in cuffless blood pressure measurement, interactive virtual reality, and human–machine interface are demonstrated. Notably, the enabled on-skin devices are dissolvable in several organic solvents and can be recycled to reduce electronic waste and manufacturing cost. Such on-skin electronics can serve as the basis for future multifunctional smart textiles with passive-cooling functionalities.

A method for direct inkjet printing of silver nanowire (Ag NW) to form transparent conductive network as the top electrode for inverted semi-transparent organic photovoltaic devices (OPV) was developed. The highest power conversion efficiency of the poly(3-hexylthiophene):phenyl-C61–butyric acid methyl ester (P3HT:PC61BM) based OPV was achieved to be 2.71% when the top electrode was formed by 7 times of printing. In general, devices with printed Ag NW top electrode had similar open-circuit voltage (VOC, around 0.60 V) but lower fill factor (FF, 0.33–0.54) than that of device with thermally deposited Ag opaque electrode (reference device). Both FF and short-circuit current density (JSC), however, were found to be increasing with the increase of printing times (3, 5, and 7), which could be partially attributed to the improved conductivity of Ag NW network electrodes. The solvent effect on device performances was studied carefully by comparing the current density-voltage (J-V) curves of different devices. The results revealed that solvent treatment on the anode buffer layer during printing led to a decrease of charge injection selectivity and an increase of charge recombination at the anode interface, which was considered to be the reason for the degrading of device performance.

The direct laser writing method has emerged as a novel technique for fabricating MoS2/carbon hybrid HER catalysts with low cost, high efficiency, and flexible designability.

With the aim of developing high‐performance flexible polymer solar cells, the preparation of flexible transparent electrodes (FTEs) via a high‐throughput gravure printing process is reported. By varying the blend ratio of the mixture solvent and the concentration of the silver nanowire (AgNW) inks, the surface tension, volatilization rate, and viscosity of the AgNW ink can be tuned to meet the requirements of gravure printing process. Following this method, uniformly printed AgNW films are prepared. Highly conductive FTEs with a sheet resistance of 10.8 Ω sq−1 and a high transparency of 95.4% (excluded substrate) are achieved, which are comparable to those of indium tin oxide electrode. In comparison with the spin‐coating process, the gravure printing process exhibits advantages of the ease of large‐area fabrication and improved uniformity, which are attributed to better ink droplet distribution over the substrate. 0.04 cm2 polymer solar cells based on gravure‐printed AgNW electrodes with PM6:Y6 as the photoactive layer show the highest power conversion efficiency (PCE) of 15.28% with an average PCE of 14.75 ± 0.35%. Owing to the good uniformity of the gravure‐printed AgNW electrode, the highest PCE of 13.61% is achieved for 1 cm2 polymer solar cells based on the gravure‐printed FTEs.