According to the forecast of Allied Market Research, the flexible electronics market is projected to reach $42.48 billion by 2027. It is estimated to revolutionize the lighting technology, power integration displays, and health monitoring systems. The popularity of flexible electronics is mainly due to the unique benefits of organic materials and devices that offer cost-effectiveness, low-temperature processability, mechanical softness, and shape adaptability, [5][6][7] which are difficult to obtain with traditional, complementary-metal-oxide-semiconductor (CMOS)-based rigid systems. [8] Over the past two decades, research interest in flexible electronic systems has grown exponentially, driven by the requirements of interface softness and shape adaptability for electronics used in Internet-of-Things (IoT), [9] human-machine interfaces, [10] and advanced healthcare. [11] Although significant progress has been made in academia, the practical application of flexible electronics in the industry is limited. Presently, thin-film photovoltaics and flexible displays mainly contribute to the flexible electronics market, with a noticeable presence held by radio frequency identification (RFID) tags and medical X-ray imagers. [12] Indeed, much of the success of present flexible electronic systems rely on the performance and reliability of thin-film The development of flexible and conformable devices, whose performance can be maintained while being continuously deformed, provides a significant step toward the realization of next-generation wearable and e-textile applications. Organic field-effect transistors (OFETs) are particularly interesting for flexible and lightweight products, because of their low-temperature solution processability, and the mechanical flexibility of organic materials that endows OFETs the natural compatibility with plastic and biodegradable substrates. Here, an in-depth review of two competing flexible OFET technologies, planar and vertical OFETs (POFETs and VOFETs, respectively) is provided. The electrical, mechanical, and physical properties of POFETs and VOFETs are critically discussed, with a focus on four pivotal applications (integrated logic circuits, light-emitting devices, memories, and sensors). It is pointed out that the flexible function of the relatively newer VOFET technology, along with its perspective on advancing the applicability of flexible POFETs, has not been reviewed so far, and the direct comparison regarding the performance of POFET-and VOFET-based flexible applications is most likely absent. With discussions spanning printed and wearable electronics, materials science, biotechnology, and environmental monitoring, this contribution is a clear stimulus to researchers working in these fields to engage toward the plentiful possibilities that POFETs and VOFETs offer to flexible electronics.

Organic electrochemical transistors (OECTs) are technologically relevant devices presenting high susceptibility to physical stimulus, chemical functionalization, and shape changes—jointly to versatility and low production costs. The OECT capability of liquid‐gating addresses both electrochemical sensing and signal amplification within a single integrated device unit. However, given the organic semiconductor time‐consuming doping process and their usual low field‐effect mobility, OECTs are frequently considered low‐end category devices. Toward high‐performance OECTs, microtubular electrochemical devices based on strain‐engineering are presented here by taking advantage of the exclusive shape features of self‐curled nanomembranes. Such novel OECTs outperform the state‐of‐the‐art organic liquid‐gated transistors, reaching lower operating voltage, improved ion doping, and a signal amplification with a >104 intrinsic gain. The multipurpose OECT concept is validated with different electrolytes and distinct nanometer‐thick molecular films, namely, phthalocyanine and thiophene derivatives. The OECTs are also applied as transducers to detect a biomarker related to neurological diseases, the neurotransmitter dopamine. The self‐curled OECTs update the premises of electrochemical energy conversion in liquid‐gated transistors, yielding a substantial performance improvement and new chemical sensing capabilities within picoliter sampling volumes.

Intermolecular electron‐transfer reactions are key processes in physics, chemistry, and biology. The electron‐transfer rates depend primarily on the system reorganization energy, that is, the energetic cost to rearrange each reactant and its surrounding environment when a charge is transferred. Despite the evident impact of electron‐transfer reactions on charge‐carrier hopping, well‐controlled electronic transport measurements using monolithically integrated electrochemical devices have not successfully measured the reorganization energies to this date. Here, it is shown that self‐rolling nanomembrane devices with strain‐engineered mechanical properties, on‐a‐chip monolithic integration, and multi‐environment operation features can overcome this challenge. The ongoing advances in nanomembrane‐origami technology allow to manufacture the nCap, a nanocapacitor platform, to perform molecular‐level charge transport characterization. Thereby, employing nCap, the copper‐phthalocyanine (CuPc) reorganization energy is probed, ≈0.93 eV, from temperature‐dependent measurements of CuPc nanometer‐thick films. Supporting the experimental findings, density functional theory calculations provide the atomistic picture of the measured CuPc charge‐transfer reaction. The experimental strategy demonstrated here is a consistent route towards determining the reorganization energy of a system formed by molecules monolithically integrated into electrochemical nanodevices.

Flexible Electronics In article number 2204804, Ali Nawaz, Carlos C. B. Bufon, and co‐workers compare the performance of planar organic transistors the emerging vertical‐transistor technology, outlining the critical device fabrication and material‐design strategies, and discussing their role and function in a wide range of flexible electronics applications. Showcasing research from the Micro Nano Facility (MNF‐SD), Bruno Kessler Foundation (FBK), Trento, Italy, in collaboration with Mackenzie Presbyterian Institute, Chemnitz University of Technology, and Queensland University of Technology.

Achieving synergy between electrochemistry and microelectronics is a hard‐hitting task. In article number 2101518, Carlos C. Bof Bufon and co‐workers employ rolling‐origami nanotechnology to build up novel organic electrochemical transistors (OECTs) featuring outstanding performance. The findings also anticipate that rolling‐origami OECTs are enormously appealing candidates to future applications in chemical and biological sensors (viz., for neurotransmitter detection).

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Multipurpose analytical platforms that can reliably be adapted to distinct targets are an essential task nowadays. Here, the conception, characterization, and application of ultracompact three-dimensional (3D) electroanalytical platforms based on...

Tiny autonomous systems less than 1 mm across need small energy storage to satisfy the demand for temporary pulse power and consistent power supply. A battery or supercapacitor alone cannot meet both requirements. Integration of battery and supercapacitor is an alternative, but it introduces a device (supercapacitor) that is not frequently invoked but requires substantial space. Herein, a submillimeter (0.42 mm2) high‐power supercapacitor with an additional function, namely, an on‐chip integrated probe for biomolecule detection is created. The dual‐function device is directly used in the liquid electrolyte, and its Swiss‐roll geometry allows for operation in a minimum 12‐nL electrolyte. The micro‐Swiss‐roll supercapacitor delivers a power density of 911 mW cm−2 and displays a 98% capacitance retention over 10 000 cycles. The biomolecule probe achieves a sensitivity of 230–262 µA mm−1 with a limit of detection of 0.4–0.5 × 10−3 m for the proof‐of‐concept target, the neurotransmitter dopamine. The biomolecule probe achieves a 230–262 µA mm−1 sensitivity with a limit of detection of 0.4–0.5 × 10−3 m for the proof‐of‐concept target, the neurotransmitter dopamine, along with selectivity in the presence of ascorbic acid. The independent dual function provides a promising route toward the full‐time use of dust‐sized supercapacitors integrated into submillimeter functional systems.