The stretchable and active multielectrode array successfully measured electrocardiography of rat during blood exposure.

Robust polymeric nanofilms can be used to construct gas-permeable soft electronics that can directly adhere to soft biological tissue for continuous, long-term biosignal monitoring. However, it is challenging to fabricate gas-permeable dry electrodes that can self-adhere to the human skin and retain their functionality for long-term (>1 d) health monitoring. We have succeeded in developing an extraordinarily robust, self-adhesive, gas-permeable nanofilm with a thickness of only 95 nm. It exhibits an extremely high skin adhesion energy per unit area of 159 μJ/cm2. The nanofilm can self-adhere to the human skin by van der Waals forces alone, for 1 wk, without any adhesive materials or tapes. The nanofilm is ultradurable, and it can support liquids that are 79,000 times heavier than its own weight with a tensile stress of 7.82 MPa. The advantageous features of its thinness, self-adhesiveness, and robustness enable a gas-permeable dry electrode comprising of a nanofilm and an Au layer, resulting in a continuous monitoring of electrocardiogram signals with a high signal-to-noise ratio (34 dB) for 1 wk.

A folding screen type OLED display was developed (Fig. 1) to demonstrate the application of a flexible display. The display surface can be bent with a curvature radius of 4 mm. To protect an OLED against moisture, inorganic passivation layers are provided on the upper and lower sides of the flexible display. Using our transfer technology, dense passivation layers can be obtained. The measured water vapor transmission rate of the layer is 7 10 6 g/m 2 day or less, which improves OLED reliability.

A nanomesh organic electrochemical transistor (NMOECT) is proposed. The NMOECT is a porous nanomesh structure, which enables the device to be comfortably laminated on human skin and simultaneously achieve local amplification. The acquisition and local amplification of the electrophysiological signals (electrocardiography) with DC-level cutoff were demonstrated using the NMOECT. A high signal-tonoise ratio of 25.896 dB was achieved. The proposed NMOECT could pave the way for on-skin electrodes that acquire high-quality biosignals.

-In this study, a 5.9-inch foldable active-matrix organic light emitting diode (AMOLED) display was developed. A folding test was performed repeatedly. The display survived the folding test (100,000 folds) with a curvature radius of 2 mm. To protect an organic light emitting diode (OLED) against moisture, inorganic passivation layers are provided on the upper and lower sides of the flexible display. Using our transfer technology, high density passivation layers can be obtained. The measured water vapor transmission rate of the layer is 7 × 10 À6 g/m 2 Áday or less, which improves OLED reliability.With these techniques, we have developed a book-type display, which is repeatedly foldable like a book, and a tri-fold display including a display area, which is foldable in three.