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As the technologies for treating diseases are attracting continuous attention, physical therapy methods, particularly electrical stimulation (ES), have been widely investigated owing to their high effectiveness. As ES essentially requires an external power source, various efforts are being devoted to achieving the application of ES to the human body using nanogenerators. Various studies have verified the effect of ES by applying the same output generated by the device to in vitro and in vivo bio‐electrical stimulation. However, it is unknown whether the electrical output generated by the device can be transmitted equally in the cell unit, and this is considered a common missing link in bio‐electrical stimulation research. Herein, the missing link between electrical devices and in vitro bio‐electrical stimulations is unraveled by the ex vivo, 2D simulation, and in vitro study of body‐mediated energy transfer (BmET) models. In addition, BmET‐based ES is applied to pre‐osteoblasts, and the increased cellular functions are verified. [ABSTRACT FROM AUTHOR]

This study demonstrates a technique for the development of 3D electronics based on planar membrane‐type devices and a supportive plastic (e.g., acrylonitrile butadiene styrene [ABS] used in this study) substrate containing internal microfluidic channels (µ‐FCs) that allow selective plasticization and transformation after the insertion of a liquid plasticizer (e.g., N,N‐dimethylformamide). The internal µ‐FC has a strong advantage of transiency and does not require an additional removal process because the channels are self‐closed by the swelling and dissolution of the plasticized regions. Furthermore, the 3D printing process to create internal µ‐FCs provides a considerable amount of freedom in channel design for sequential plasticization and transformation into complex structures. Using this method, extreme scenarios that involve complete bending of the metal electrodes and indium gallium zinc oxide thin‐film transistors laminated to the ABS substrates without electrical failure are possible, regardless of the bending direction and the vertical position of the electrode of the plastic substrate. Finally, a truncated octahedral light‐emitting diode display is successfully developed by multiple cycles of sequential plasticization and transformation processes to demonstrate the feasibility of this method. [ABSTRACT FROM AUTHOR]

To create ultrathin sticker-type electronic devices that can be attached to unconventional substrates, it is highly desirable to develop printable membrane-type electronics on a handling substrate and then transfer the printing to a target surface. A facile method is presented for high-efficiency transfer printing by controlling the interfacial adhesion between a handling substrate and an ultrathin substrate in a systematic manner under mild conditions. A water-soluble sacrificial polymer layer is employed on a dimpled handling substrate, which enables the topological confinement of the polymer residue inside and near the dimples during the etching and drying processes to reduce the interfacial adhesion gently, creating a high yield of transfer printing in a deterministic manner. As an example of an electronic device that was created using this method, a highly flexible sticker-type ZnO thin film transistor was successfully developed with a thickness of 13 μm including a printable ultrathin substrate, which can be attached to various substrates, such as paper, plastic, and stickers. [ABSTRACT FROM AUTHOR]

This work demonstrates a means of automatic transformation from planar electronic devices to desirable 3D forms. The method uses a spatially designed thermoplastic framework created via extrusion shear printing of acrylonitrile–butadiene–styrene (ABS) on a stress‐free ABS film, which can be laminated to a membrane‐type electronic device layer. Thermal annealing above the glass transition temperature allows stress relaxation in the printed polymer chains, resulting in an overall shape transformation of the framework. In addition, the significant reduction in the Young's modulus and the ability of the polymer chains to reflow in the rubbery state release the stress concentration in the electronic device layer, which can be positioned outside the neutral mechanical plane. Electrical analyses and mechanical simulations of a membrane‐type Au electrode and indium gallium zinc oxide transistor arrays before and after transformation confirm the versatility of this method for developing 3D electronic devices based on planar forms. [ABSTRACT FROM AUTHOR]

We demonstrate the modulation of electrical switching properties through the interconnection of multiple nanoscale channels (∼600 nm) in a single VO 2 nanobeam with a coexisting metal-insulator (M-I) domain configuration during phase transition. The Raman scattering characteristics of the synthesized VO 2 nanobeams provide evidence that substrate-induced interfacial strain can be inhomogeneously distributed along the length of the nanobeam. Interestingly, the nanoscale VO 2 devices with the same channel length and width exhibit distinct differences in hysteric current-voltage characteristics, which are explained by theoretical calculations of resistance change combined with Joule heating simulations of the nanoscale VO 2 channels. The observed results can be attributed to the difference in the spatial distribution and fraction ratios of M-I domains due to interfacial strain in the nanoscale VO 2 channels during the metal-insulator transition process. Moreover, we demonstrate the electrically activated resistive switching characteristics based on the hysteresis behaviors of the interconnected nanoscale channels, implying the possibility of manipulating multiple resistive states. Our results may offer insights into the nanoscale engineering of correlated phases in VO 2 as the key materials of neuromorphic computing for which nonlinear conductance is essential.