Room temperature high-efficiency welding of an ultra-long silver nanowire network for flexible transparent electrodes.

In the preparation of flexible electronic devices, obtaining a transparent conductive electrode with high electrical conductivity, high transparency, and mechanical flexibility is a significant challenge. This study developed a simple method for preparing ultra-long silver nanowires (ul-AgNWs), obtaining high-purity ul-AgNWs with an average length of 317.66 ± 98.

Multimode opto-magnetic dual-responsive actuating fibers and fabrics programmed direct ink writing.

Current methods lack one-step actuation programming for weave structures that can achieve multimodal motions in fiber and fabric actuators. Fiber and fabric actuators with dual-response to magnetic fields and near-infrared (NIR) light were fabricated direct ink writing (DIW) in this work, and have 105.3 J kg energy density, enabling multimodal motions including rolling, grasping, and transportation.

Integrated opposite charge grafting induced ionic-junction fiber.

The emergence of ionic-junction devices has attracted growing interests due to the potential of serving as signal transmission and translation media between electronic devices and biological systems using ions. Among them, fiber-shaped iontronics possesses a great advantage in implantable applications owing to the unique one-dimensional geometry. However, fabricating stable ionic-junction on curved surfaces remains a challenge.

Soft Fiber Electronics Based on Semiconducting Polymer.

Fibers, originating from nature and mastered by human, have woven their way throughout the entire history of human civilization. Recent developments in semiconducting polymer materials have further endowed fibers and textiles with various electronic functions, which are attractive in applications such as information interfacing, personalized medicine, and clean energy. Owing to their ability to be easily integrated into daily life, soft fiber electronics based on semiconducting polymers have gained popularity recently for wearable and implantable applications.

Broadband and High-Efficiency Microwave Absorbers Based on Pyramid Structure.

Microwave-absorbing materials with wide bandwidth and high absorptivity are increasingly playing an important role in over-the-air (OTA) testing. In this work, a kind of pyramid absorbing material was prepared using flame-retardant absorbers as the filler. In addition, a coating was used to further improve the flame-retardant properties of the microwave-absorbing material.

Thiazole Imide-Based All-Acceptor Homopolymer with Branched Ethylene Glycol Side Chains for Organic Thermoelectrics.

n-Type semiconducting polymers with high thermoelectric performance remain challenging due to the scarcity of molecular design strategy, limiting their applications in organic thermoelectric (OTE) devices. Herein, we provide a new approach to enhance the OTE performance of n-doped polymers by introducing acceptor-acceptor (A-A) type backbone bearing branched ethylene glycol (EG) side chains. When doped with 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine (N-DMBI), the A-A homopolymer PDTzTI-TEG exhibits n-type electrical conductivity (σ) up to 34 S cm and power factor value of 15.

Wearable Thermoelectric Materials and Devices for Self-Powered Electronic Systems.

The emergence of artificial intelligence and the Internet of Things has led to a growing demand for wearable and maintenance-free power sources. The continual push toward lower operating voltages and power consumption in modern integrated circuits has made the development of devices powered by body heat finally feasible. In this context, thermoelectric (TE) materials have emerged as promising candidates for the effective conversion of body heat into electricity to power wearable devices without being limited by environmental conditions.

A high-conductivity n-type polymeric ink for printed electronics.

Conducting polymers, such as the p-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), have enabled the development of an array of opto- and bio-electronics devices. However, to make these technologies truly pervasive, stable and easily processable, n-doped conducting polymers are also needed. Despite major efforts, no n-type equivalents to the benchmark PEDOT:PSS exist to date.

Amphipathic Side Chain of a Conjugated Polymer Optimizes Dopant Location toward Efficient N-Type Organic Thermoelectrics.

There is no molecular strategy for selectively increasing the Seebeck coefficient without reducing the electrical conductivity for organic thermoelectrics. Here, it is reported that the use of amphipathic side chains in an n-type donor-acceptor copolymer can selectively increase the Seebeck coefficient and thus increase the power factor by a factor of ≈5. The amphipathic side chain contains an alkyl chain segment as a spacer between the polymer backbone and an ethylene glycol type chain segment.

High Thermoelectric Performance in n-Type Perylene Bisimide Induced by the Soret Effect.

Low-cost, non-toxic, abundant organic thermoelectric materials are currently under investigation for use as potential alternatives for the production of electricity from waste heat. While organic conductors reach electrical conductivities as high as their inorganic counterparts, they suffer from an overall low thermoelectric figure of merit (ZT) due to their small Seebeck coefficient. Moreover, the lack of efficient n-type organic materials still represents a major challenge when trying to fabricate efficient organic thermoelectric modules.

Ground-state electron transfer in all-polymer donor-acceptor heterojunctions.

Doping of organic semiconductors is crucial for the operation of organic (opto)electronic and electrochemical devices. Typically, this is achieved by adding heterogeneous dopant molecules to the polymer bulk, often resulting in poor stability and performance due to dopant sublimation or aggregation. In small-molecule donor-acceptor systems, charge transfer can yield high and stable electrical conductivities, an approach not yet explored in all-conjugated polymer systems.

Conductive polymer nanoantennas for dynamic organic plasmonics.

Being able to dynamically shape light at the nanoscale is one of the ultimate goals in nano-optics. Resonant light-matter interaction can be achieved using conventional plasmonics based on metal nanostructures, but their tunability is highly limited due to a fixed permittivity. Materials with switchable states and methods for dynamic control of light-matter interaction at the nanoscale are therefore desired.

Double doping of conjugated polymers with monomer molecular dopants.

Molecular doping is a crucial tool for controlling the charge-carrier concentration in organic semiconductors. Each dopant molecule is commonly thought to give rise to only one polaron, leading to a maximum of one donor:acceptor charge-transfer complex and hence an ionization efficiency of 100%. However, this theoretical limit is rarely achieved because of incomplete charge transfer and the presence of unreacted dopant.

A Chemically Doped Naphthalenediimide-Bithiazole Polymer for n-Type Organic Thermoelectrics.

The synthesis of a novel naphthalenediimide (NDI)-bithiazole (Tz2)-based polymer [P(NDI2OD-Tz2)] is reported, and structural, thin-film morphological, as well as charge transport and thermoelectric properties are compared to the parent and widely investigated NDI-bithiophene (T2) polymer [P(NDI2OD-T2)]. Since the steric repulsions in Tz2 are far lower than in T2, P(NDI2OD-Tz2) exhibits a more planar and rigid backbone, enhancing π-π chain stacking and intermolecular interactions. In addition, the electron-deficient nature of Tz2 enhances the polymer electron affinity, thus reducing the polymer donor-acceptor character.

Enhanced n-Doping Efficiency of a Naphthalenediimide-Based Copolymer through Polar Side Chains for Organic Thermoelectrics.

N-doping of conjugated polymers either requires a high dopant fraction or yields a low electrical conductivity because of their poor compatibility with molecular dopants. We explore n-doping of the polar naphthalenediimide-bithiophene copolymer p(gNDI-gT2) that carries oligoethylene glycol-based side chains and show that the polymer displays superior miscibility with the benzimidazole-dimethylbenzenamine-based n-dopant N-DMBI. The good compatibility of p(gNDI-gT2) and N-DMBI results in a relatively high doping efficiency of 13% for n-dopants, which leads to a high electrical conductivity of more than 10 S cm for a dopant concentration of only 10 mol % when measured in an inert atmosphere.

Complementary Logic Circuits Based on High-Performance n-Type Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) have been the subject of intense research in recent years. To date, however, most of the reported OECTs rely entirely on p-type (hole transport) operation, while electron transporting (n-type) OECTs are rare. The combination of efficient and stable p-type and n-type OECTs would allow for the development of complementary circuits, dramatically advancing the sophistication of OECT-based technologies.

Rosin-enabled ultraclean and damage-free transfer of graphene for large-area flexible organic light-emitting diodes.

The large polymer particle residue generated during the transfer process of graphene grown by chemical vapour deposition is a critical issue that limits its use in large-area thin-film devices such as organic light-emitting diodes. The available lighting areas of the graphene-based organic light-emitting diodes reported so far are usually <1 cm. Here we report a transfer method using rosin as a support layer, whose weak interaction with graphene, good solubility and sufficient strength enable ultraclean and damage-free transfer.

Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers.

Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.

Organic semiconductor heterojunctions: electrode-independent charge injectors for high-performance organic light-emitting diodes.

Organic light-emitting diodes (OLEDs) are driven by injected charges from an anode and a cathode. The low and high work function metals are necessary for the effective injection of electrons and holes, respectively. Here, we introduce a fully novel design concept using organic semiconductor heterojunctions (OSHJs) as the charge injectors for achieving highly efficient OLEDs, regardless of the work functions of the electrodes.

Achieving Extreme Utilization of Excitons by an Efficient Sandwich-Type Emissive Layer Architecture for Reduced Efficiency Roll-Off and Improved Operational Stability in Organic Light-Emitting Diodes.

It has been demonstrated that the efficiency roll-off is generally caused by the accumulation of excitons or charge carriers, which is intimately related to the emissive layer (EML) architecture in organic light-emitting diodes (OLEDs). In this article, an efficient sandwich-type EML structure with a mixed-host EML sandwiched between two single-host EMLs was designed to eliminate this accumulation, thus simultaneously achieving high efficiency, low efficiency roll-off and good operational stability in the resulting OLEDs. The devices show excellent electroluminescence performances, realizing a maximum external quantum efficiency (EQE) of 24.