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Organic diodes consisting of molecular nano-pyramid structures sandwiched between metal and strained nano-membrane electrodes are created. The robust and smooth contacts provided by self-curled metal layers render the molecular nano-pyramids efficent channels for detecting nitrogen dioxide airflow.

www.advmat.de www.advancedsciencenews.com photolithography techniques. New amorphous semiconducting materials are involved in the development of flexible electronics based on high-performance compounds that include organic [82] and inorganic (e.g., copper oxide [83] or indium-gallium-zinc oxide (IGZO) [84] ) semiconductor possessing, for instance, the transparency [85] required in optoelectronic applications. Once fabricated on polymeric ultrathin substrates, these devices offer the flexibility, stretchability, and imperceptibility [85][86][87] for onskin (Figure 3 a,b,d) biomedical applications, such as biosensors capable of conformally wrapping a soft or irregularly shaped 3D biological sample such as a cancer cell or a pollen grain. [88] Demonstrating outstanding mechanical stability, thin-film materials, in particular semiconductors, are superior candidates for 3D applications compared to monocrystalline semiconductors. [87,89,90] Good examples are amorphous oxides and some organic molecular semiconductors [82] (Figure 3b-d) which are particularly attractive for 3D self-assembled microelectronics. By employing substrates with a thickness in the micro-and submicrometer range (Figure 3) many issues associated with mechanical stress on the surface could be mitigated, demonstrating the increased robustness and reliability of thinfilm electronics. [87,89] Electronic skin (e-skin) (Figure 3a,b,d), for Adv. Mater. 2020, 32, 1902994 Adv. Mater. 2020, 32, 1902994 Figure 3. Thin-film flexible electronic devices and applications. a) Mechanical prosthesis with stretchable electronic skin. Adapted with permission. [97] Copyright 2014, Springer Nature. b) Schematics and photograph of imperceptible organic electronics equipped with tactile active sensor matrix. Adapted with permission. [87] Copyright 2013, Springer Nature. c) Complex circuits with 8-bit microprocessors made of 3381 organic thin-film transistors. Adapted with permission. [98] Copyright 2012, IEEE. d) Ultrathin substrate combined with high-performance indium-gallium-zinc oxide (IGZO) circuitry paving the way for active medical devices on contact lenses. [85] Adapted with permission. [85] Copyright 2014, Springer Nature.

Inspired by origami art, we demonstrate a tubular microsupercapacitor (TMSC) by self-assembling two-dimensional (2D) films into a "swiss roll" structure with greatly reduced footprint area. A polymeric framework consisting of swelling hydrogel and polyimide layers ensures excellent ion transport between poly(3,4-ethylenedioxythiophene) (PEDOT)-based electrodes and provides efficient self-protection of the TMSC against external compression up to about 30 MPa. Such TMSCs exhibit an areal capacitance of 82.5 mF cm −2 at 0.3 mA cm −2 with a potential window of 0.8 V, an energy density and power density of 7.73 μWh cm −2 and 17.8 mW cm −2 (0.3 and 45 mA cm −2 ), and an improved cycling stability with a capacitance retention up to 96.6% over 5000 cycles. Furthermore, asfabricated TMSC arrays can be detached from their surface and transferred onto target substrates. The connection of devices in parallel/series greatly improves their capacity and voltage output. Overall, our prototype devices and fabrication methodology provide a promising route to create integratable microscale tubular energy storage devices with an efficient self-protection function and high performance for future miniaturized electronics.

Magnetic sensors are widely used in our daily life for assessing the position and orientation of objects. Recently, the magnetic sensing modality has been introduced to electronic skins (e-skins), enabling remote perception of moving objects. However, the integration density of magnetic sensors is limited and the vector properties of the magnetic field cannot be fully explored since the sensors can only perceive field components in one or two dimensions. Here, we report an approach to fabricate high-density integrated active matrix magnetic sensor with three-dimensional (3D) magnetic vector field sensing capability. The 3D magnetic sensor is composed of an array of self-assembled micro-origami cubic architectures with biased anisotropic magnetoresistance (AMR) sensors manufactured in a wafer-scale process. Integrating the 3D magnetic sensors into an e-skin with embedded magnetic hairs enables real-time multidirectional tactile perception. We demonstrate a versatile approach for the fabrication of active matrix integrated 3D sensor arrays using micro-origami and pave the way for new electronic devices relying on the autonomous rearrangement of functional elements in space.

Today’s smallest energy storage devices for in-vivo applications are larger than 3 mm3 and lack the ability to continuously drive the complex functions of smart dust electronic and microrobotic systems. Here, we create a tubular biosupercapacitor occupying a mere volume of 1/1000 mm3 (=1 nanoliter), yet delivering up to 1.6 V in blood. The tubular geometry of this nano-biosupercapacitor provides efficient self-protection against external forces from pulsating blood or muscle contraction. Redox enzymes and living cells, naturally present in blood boost the performance of the device by 40% and help to solve the self-discharging problem persistently encountered by miniaturized supercapacitors. At full capacity, the nano-biosupercapacitors drive a complex integrated sensor system to measure the pH-value in blood. This demonstration opens up opportunities for next generation intravascular implants and microrobotic systems operating in hard-to-reach small spaces deep inside the human body.

Considerable efforts have been made to realize nanoscale diodes based on single molecules or molecular ensembles for implementing the concept of molecular electronics. However, so far, functional molecular diodes have only been demonstrated in the very low alternating current frequency regime, which is partially due to their extremely low conductance and the poor degree of device integration. Here, we report about fully integrated rectifiers with microtubular soft-contacts, which are based on a molecularly thin organic heterojunction and are able to convert alternating current with a frequency of up to 10 MHz. The unidirectional current behavior of our devices originates mainly from the intrinsically different surfaces of the bottom planar and top microtubular Au electrodes while the excellent high frequency response benefits from the charge accumulation in the phthalocyanine molecular heterojunction, which not only improves the charge injection but also increases the carrier density.

The rapid development of microelectronics has equally rapidly increased the demand for miniaturized energy storage devices. On‐chip microsupercapacitors (MSCs), as promising power candidates, possess great potential to complement or replace electrolytic capacitors and microbatteries in various applications. However, the areal capacities and energy densities of the planar MSCs are commonly limited by the low voltage window, the thin layer of the electrode materials and complex fabrication processes. Here, a new‐type three‐dimensional (3D) tubular asymmetric MSC with small footprint area, high potential window, ultrahigh areal energy density, and long‐term cycling stability is fabricated with shapeable materials and photolithographic technologies, which are compatible with modern microelectronic fabrication procedures widely used in industry. Benefiting from the novel architecture, the 3D asymmetric MSC displays an ultrahigh areal capacitance of 88.6 mF cm−2 and areal energy density of 28.69 mW h cm−2, superior to most reported interdigitated MSCs. Furthermore, the 3D tubular MSCs demonstrate remarkable cycling stability and the capacitance retention is up to 91.8% over 12 000 cycles. It is believed that the efficient fabrication methodology can be used to construct various integratable microscale tubular energy storage devices with small footprint area and high performance for miniaturized electronics.