1,720,971 research outputs found
Reconfigurable microwave metadevices based on organic electrochemical transistors
No full textElectrically tunable metadevices can add novel functionalities to electronic and electromagnetic systems such as antennas and cloaking technologies. However, current microwave metadevices are based on materials that require sophisticated and expensive fabrication processes, and are not compatible with large-area and high-throughput deposition techniques on flexible platforms. Here we report reconfigurable microwave resonators that are electrically tuned by organic electrochemical transistors. The devices are fabricated via inkjet printing onto polyimide substrates using commercial metal nanoparticle and conducting polymer inks. By applying electrostatic gating to the polymer—a mixed ion–electron conductor—we show that the amplitude and frequency of different microwave resonant structures, including individual magnetic and electric split-ring resonators as well as a metasurface, can be modulated in the sub-5-GHz range
Towards a Chipless and Wireless Passive System for Real-Time Encoding of the Bladder Volume
No full textNeurogenic bladder and other lower urinary tract dysfunctions represent a significant health hazard and life-quality impairment in individuals suffering from neurological disorders. A few implantable and wearable technologies have been proposed to partially recover bladder functionality, mostly based on resistive and capacitive strain gauges designed to be surgically placed inside the pelvic cavity. In this work, an alternative proof-of-concept device for monitoring the volumetric changes of the bladder is presented, where the sensing element is based on a capacitive linear encoder integrated with a passive wireless radio-frequency resonator, which can be remotely interrogated. The sliding mechanism at the core of the proposed system allows a wide sensing range without stringent requirements on materials properties and overall device stability
Inkjet-printed lasing silk text on reusable distributed feedback boards
Full text linkInkjet printing is an attractive bottom-up microfabrication technology owing to its simplicity, ease of use, and low cost. This method is particularly suitable for patterning of biomaterials because biofunctionality and bioactivity can be preserved during the patterning process in the absence of harsh conditions such as heat, UV radiation, and plasma. However, it is still challenging to apply this technology to biomaterial-based soft photonics, which requires precise control over morphology and uniformity to confine photons efficiently. This study introduces inkjet printing to create silk protein patterns to emit/guide a single-mode distributed feedback (DFB) laser on a single platform. A thin TiO2 coated grating enables coherent feedback of the generated photons for any shape of the printed silk pattern. The lasing wavelength can be adjusted by adding gold nanoparticles to the silk/dye ink. Photonic components of lasers and waveguides are drawn on a DFB board, and the lasing light can be extracted through adjacent waveguides. The printed components can be reformed by post modification (water-removal and reprinting). Additionally, optically absorptive melanin nanoparticles placed on the waveguide can attenuate the propagating light, thus adding utility for sensing applications. This allows a new method to fabricate cost-effective, easily functionalized, and versatile biomaterial photonic chips for advanced sensing and diagnosis
Silk fibroin as a surfactant for water-based nanofabrication
No full textWater-based processing plays a crucial role in high technology, especially in electronics, material sciences and life sciences, with important implications in the development of high-quality reliable devices, fabrication efficiency, safety and sustainability. At the micro- and nanoscale, water is uniquely enabling as a bridge between biological and technological systems. However, new approaches are needed to overcome fundamental challenges that arise from the high surface tension of water, which hinders wetting and, thus, fabrication at the bio-nano interface. Here we report the use of silk fibroin as a surfactant to enable water-based processing of nanoscale devices. Even in minute quantities (for example, 0.01 w/v%), silk fibroin considerably enhances surface coverage and outperforms commercial surfactants in precisely controlling interfacial energy between water-based solutions and hydrophobic surfaces. This effect is ascribed to the amphiphilic nature of the silk molecule and its adaptive adsorption onto substrates with diverse surface energy, facilitating intermolecular interactions between unlikely pairs of materials. The approach's versatility is highlighted by manufacturing water-processed nanodevices, ranging from transistors to photovoltaic cells. Its performance is found to be equivalent to analogous vacuum-processed devices, underscoring the utility and versatility of this approach for water-based nanofabrication.The amphiphilic nature of silk fibroin makes it a natural surfactant. Here it is shown to mediate interface interactions, enabling the wetting of hydrophobic surfaces with aqueous solutions and facilitating water-processed nanodevice fabrication without previous surface modification
Tattoo-Paper Transfer as a Versatile Platform for All-Printed Organic Edible Electronics
No full textThe use of natural or bioinspired materials to develop edible electronic devices is a potentially disruptive technology that can boost point-of-care testing. The technology exploits devices that can be safely ingested, along with pills or even food, and operated from within the gastrointestinal tract. Ingestible electronics can potentially target a significant number of biomedical applications, both as therapeutic and diagnostic tool, and this technology may also impact the food industry, by providing ingestible or food-compatible electronic tags that can “smart” track goods and monitor their quality along the distribution chain. Temporary tattoo-paper is hereby proposed as a simple and versatile platform for the integration of electronics onto food and pharmaceutical capsules. In particular, the fabrication of all-printed organic field-effect transistors on untreated commercial tattoo-paper, and their subsequent transfer and operation on edible substrates with a complex nonplanar geometry is demonstrated
Fully Degradable Food-Based Solenoids and Radio Frequency Circuits for Green Electronics
Full text linkHerein, edible solenoids are introduced, which are realized by coating spaghetti with edible gold leaves, creating fully edible and functional radio frequency (RF) electronic components. As a proof-of-principle of their use in RF circuits, a completely edible passive inductor-capacitor (LC) resonator at approximate to 200 MHz is demonstrated. The results significantly expand the applications of edible electronics to RF regime, supporting future developments in edible sensing and edible robotic systems, emerging fields with a high grade of sustainability
Uniaxial Alignment of Conjugated Polymer Films for High-Performance Organic Field-Effect Transistors
No full textPolymer semiconductors have been experiencing a remarkable improvement in electronic and optoelectronic properties, which are largely related to the recent development of a vast library of high-performance, donor–acceptor copolymers showing alternation of chemical moieties with different electronic affinities along their backbones. Such steady improvement is making conjugated polymers even more appealing for large-area and flexible electronic applications, from distributed and portable electronics to healthcare devices, where cost-effective manufacturing, light weight, and ease of integration represent key benefits. Recently, a strong boost to charge carrier mobility in polymer-based field-effect transistors, consistently achieving the range from 1.0 to 10 cm2 V−1 s−1 for both holes and electrons, has been given by uniaxial backbone alignment of polymers in thin films, inducing strong transport anisotropy and favoring enhanced transport properties along the alignment direction. Herein, an overview on this topic is provided with a focus on the processing–structure–property relationships that enable the controlled and uniform alignment of polymer films over large areas with scalable processes. The key aspects are specific molecular structures, such as planarized backbones with a reduced degree of conformational disorder, solution formulation with controlled aggregation, and deposition techniques inducing suitable directional flow
Mixed Ionic–Electronic Conduction, a Multifunctional Property in Organic Conductors
No full textOrganic mixed ionic–electronic conductors (OMIECs) have gained recent interest and rapid development due to their versatility in diverse applications ranging from sensing, actuation and computation to energy harvesting/storage, and information transfer. Their multifunctional properties arise from their ability to simultaneously participate in redox reactions as well as modulation of ionic and electronic charge density throughout the bulk of the material. Most importantly, the ability to access charge states with deep modulation through a large extent of its density of states and physical volume of the material enables OMIEC-based devices to display exciting new characteristics and opens up new degrees of freedom in device design. Leveraging the infinite possibilities of the organic synthetic toolbox, this perspective highlights several chemical and structural design approaches to modify OMIECs’ properties important in device applications such as electronic and ionic conductivity, color, modulus, etc. Additionally, the ability for OMIECs to respond to external stimuli and transduce signals to myriad types of outputs has accelerated their development in smart systems. This perspective further illustrates how various stimuli such as electrical, chemical, and optical inputs fundamentally change OMIECs’ properties dynamically and how these changes can be utilized in device applications
Dynamic spatio-temporal control of naturally sourced soft photonic crystals
Full text linkThe quest for flexible curvilinear displays is driving renewed interest in natural soft photonic systems that rely on the adaptable response of nanostructured living tissues to external stimuli for camouflage and energy management. Understanding and controlling the dynamics of these systems is challenging due to difficulties in sourcing the tissues and constraints in the ability to stimulate them. Here, we present an ex-vivo approach to systematically investigate soft biophotonic crystals and dynamically control their response by using the Bos taurus tapetum as a model system. The tapetum’s structural color is controlled chemically and electronically and examined by multispectral imaging providing insights on the color change dynamics. The ability to spatio-temporally control the optical response of biophotonic crystals provides insights for the development of soft photonic systems for displays and dynamic light management
Conjugated Polymers for Microwave Applications: Untethered Sensing Platforms and Multifunctional Devices
Full text linkIn the past two decades, organic electronic materials have enabled and accelerated a large and diverse set of technologies, from energy-harvesting devices and electromechanical actuators, to flexible and printed (opto)electronic circuitry. Among organic (semi)conductors, organic mixed ion–electronic conductors (OMIECs) are now at the center of renewed interest in organic electronics, as they are key drivers of recent developments in the fields of bioelectronics, energy storage, and neuromorphic computing. However, due to the relatively slow switching dynamics of organic electronics, their application in microwave technology, until recently, has been overlooked. Nonetheless, other unique properties of OMIECs, such as their substantial electrochemical tunability, charge-modulation range, and processability, make this field of use ripe with opportunities. In this work, the use of a series of solution-processed intrinsic OMIECs is demonstrated to actively tune the properties of metamaterial-inspired microwave devices, including an untethered bioelectrochemical sensing platform that requires no external power, and a tunable resonating structure with independent amplitude- and frequency-modulation. These devices showcase the considerable potential of OMIEC-based metadevices in autonomous bioelectronics and reconfigurable microwave optics
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