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Manufacturing strategies to create three‐dimensional (3D) structures with multifunctional nanomaterials are of intense interest for fabricating building blocks in many electromechanical applications. A coil spring composed of graphene provides an important step toward the realization of all‐carbon devices, as it is one of the essential elements for a wide range of systems. In this connection, here an unprecedented fabrication strategy to create a new type of 3D coil spring composed of laser‐induced graphene springs (LIG‐S) which is spontaneously produced via the pyrolytic jetting technique, is presented. Similar to wood or metal shavings observed in traditional machining processes, a pair of LIG‐S with two opposite chiralities and controllable macroscopic dimensions is produced by a single scanning of a focused continuous‐wave (CW) laser on a polyimide (PI) substrate. The resulting LIG‐S, plastic shavings by laser, exhibits sufficient mechanical and electrical properties to enable many applications including strain‐tolerant spring electrodes, antennas, supercapacitors, gas sensors, and luminescent filaments under extreme conditions. Without using any conventional fabrication techniques or other labor‐intensive, time‐consuming, and expensive processes, this novel approach enables a high‐throughput mass production of macro‐, micro‐, and nanoscale featured LIG‐S that can be manufactured within seconds to realize many open opportunities in all‐carbon electromechanical systems. [ABSTRACT FROM AUTHOR]

Quick progress in the field of smart wearable devices requires self‐sustainable power systems to help the devices execute the desired functions within a sufficient time scale. Because these devices have started to become small, light, compliant, complex, and multifunctional, it is challenging to provide them with the large amounts of energy necessary for their operation. Thus, future multifunctional wearable devices should not only incorporate mechanical flexibility for conformal contacts but also include sustainable energy units for stable operation. Hence, strategies for designing the assembly of nanoscale materials in macroscale‐structured devices have attracted intense interest, with an aim to achieve mechanically deformable and sustainable wearable devices while exploiting the recent advances in nanomaterials and device fabrication. This review highlights the recent progress in nanomaterial‐enabled and structured energy harvesting, energy storage, and hybrid devices for powering sustainable wearables. In particular, one summarizes describe biomechanical energy harvesters (piezoelectric nanogenerators and triboelectric nanogenerators), solar energy harvesters (solar cells), biothermal energy harvesters (thermoelectric nanogenerators), energy storage devices (batteries and supercapacitors), and hybrid devices and focus on the use of nanomaterials and device configurations in 1D, 2D, and 3D structures, with an aim to shape the future demand for self‐sustainable wearables. [ABSTRACT FROM AUTHOR]

Liquid precursor‐based laser‐induced reductive patterning techniques enable fast and economical fabrication of flexible electronics. Herein, an eco‐friendly and particle‐free copper ionic solution for laser‐induced reductive patterning of copper microlines on a low glass transition temperature and transparent flexible substrate is successfully developed. The solvent used is water and the reducing agent is l‐ascorbic acid. A continuous wave 640 nm laser is used as the heat source to initiate the reductive reaction and to deposit copper microlines on the substrate surface. The resistivity of the copper microlines fabricated with optimized laser parameters is remarkably low at 4.7 μΩ cm. To further improve the electrical conductivity and to enhance mechanical durability, the fabricated microlines are annealed using the same laser after the copper ionic liquid precursor is removed. The microstructures and mechanical robustness of the copper microlines, as well as the adhesion between the copper microlines and the substrate, are investigated by cyclic bending test, pull‐off test and scanning electron microscope analyses. Up to 39% reduction of electrical resistance and up to 77% enhancement of mechanical durability after a 1000 cycle bending test can be achieved by laser postprocessing. [ABSTRACT FROM AUTHOR]