Flexible organic−inorganic hybrids are promising thermoelectric materials to recycle waste heat in versatile formats. However, current organic/inorganic hybrids suffer from inferior thermoelectric properties due to aggregate nanostructures. Here we demonstrate flexible organic−inorganic hybrids where size-tunable Bi2Te3 nanoparticles are discontinuously monodispersed in the continuous conductive polymer phase, completely distinct from traditional bi-continuous hybrids. Periodic nanofillers significantly scatter phonons while continuous conducting polymer phase provides favored electronic transport, resulting in ultrahigh power factor of ~1350 μW m−1 K−2 and ultralow in-plane thermal conductivity of ~0.7 W m−1 K−1. Consequently, figure-of-merit (ZT) of 0.58 is obtained at room temperature, outperforming all reported organic materials and organic−inorganic hybrids. Thermoelectric properties of as-fabricated hybrids show negligible change for bending 100 cycles, indicating superior mechanical flexibility. These findings provide significant scientific foundation for shaping flexible thermoelectric functionality via synergistic integration of organic and inorganic components.

Human motion analysis consists of real‐time monitoring and recording of human body's kinematics. It is very essential to track ambulatory and daily‐life human motion, which is crucial for many applications and disciplines. Electronic textiles (e‐textiles) afford a valid alternative to traditional solid‐state sensors due to their merits of low cost, lightweight, flexibility, and feasibility to fit various human bodies. In this mini‐review, textile‐based sensor platforms and human motion analysis are well discussed in Section 1. Second, theoretical principles of textile‐based strain sensors are introduced including resistive, capacitive, and piezoelectrical sensors. Section 3 focuses on various types of textile materials that are functionalized as sensing systems by intrinsic or extrinsic modifications. Section 4 summaries various types of e‐textile‐based strain sensors for human motion analysis. The final two sections mainly present perspectives and challenges, and conclusions, respectively.

The Galaxy is filled with cosmic-ray particles, mostly protons with kinetic energies greater than hundreds of megaelectronvolts. Around Earth, trapped energetic protons, electrons and other particles circulate at altitudes from about 500 to 40,000 kilometres in the Van Allen radiation belts. Soon after these radiation belts were discovered six decades ago, it was recognized that the main source of inner-belt protons (with kinetic energies of tens to hundreds of megaelectronvolts) is cosmic-ray albedo neutron decay (CRAND). In this process, cosmic rays that reach the upper atmosphere interact with neutral atoms to produce albedo neutrons, which, being prone to β-decay, are a possible source of geomagnetically trapped protons and electrons. These protons would retain most of the kinetic energy of the neutrons, while the electrons would have lower energies, mostly less than one megaelectronvolt. The viability of CRAND as an electron source has, however, been uncertain, because measurements have shown that the electron intensity in the inner Van Allen belt can vary greatly, while the neutron-decay rate should be almost constant. Here we report measurements of relativistic electrons near the inner edge of the inner radiation belt. We demonstrate that the main source of these electrons is indeed CRAND, and that this process also contributes to electrons in the inner belt elsewhere. Furthermore, measurement of the intensity of electrons generated by CRAND provides an experimental determination of the neutron density in near-Earth space-2 × 10 per cubic centimetre-confirming theoretical estimates.

Graphene fiber-based supercapacitors (GFSCs) hold high power density, fast charge-discharge rate, ultralong cycling life, exceptional mechanical/electrical properties, and safe operation conditions, making them very promising to power small wearable electronics. However, the electrochemical performance is still limited by the severe stacking of graphene sheets, hydrophobicity of graphene fibers, and complex preparation process. In this work, we develop a facile but robust strategy to easily enhance electrochemical properties of all-solid-state GFSCs by simple plasma treatment. We find that 1 min plasma treatment under an ambient condition results in 33.1% enhancement of areal specific capacitance (36.25 mF/cm) in comparison to the as-prepared GFSC. The energy density reaches 0.80 μW h/cm in polyvinyl alcohol/HSO gel electrolyte and 18.12 μW h/cm in poly(vinylidene difluoride)/ethyl-3-methylimidazolium tetrafluoroborate electrolyte, which are 22 times of that of as-prepared ones. The plasma-treated GFSCs also exhibit ultrahigh rate capability (69.13% for 40 s plasma-treated ones) and superior cycle stability (96.14% capacitance retention after 20 000 cycles for 1 min plasma-treated ones). This plasma strategy can be extended to mass-manufacture high-performance carbonaceous fiber-based supercapacitors, such as graphene and carbon nanotube-based ones.

Fiber and/or yarn-shaped supercapacitors (FSSCs) have tremendous potential applications in portable and wearable electronics because of their light weight, good flexibility, and weavability. However, FSSCs usually show low energy density, which hinders their wide applications in wearable electronics. It remains challenging for the FSSCs to enhance their energy densities without sacrificing the flexibility and mechanical properties. Herein, we develop a chemical polymerization strategy to fabricate core–sheath porous polyaniline nanorods/graphene fibers which are used as the FSSCs electrode and show excellent electrochemical performances. The assembled polyaniline nanorods/graphene FSSCs exhibit an ultrahigh capacitance of 357.1 mF/cm2, a high energy density of 7.93 μWh/cm2 (5.7 mWh/cm3), and a power density of 0.23 mW/cm2 (167.7 mW/cm3). In addition, the FSSCs show ultralong cycling life (3.8% capacitance loss, 5000 charge–discharge tests), good rate capability (78.9% capacitance retention), and flexibility. The electrochemical performance of polyaniline nanorods/graphene FSSCs exceeds most reported hybrid FSSCs containing conducting polymers and/or metal oxide. This work may pave the way in structure design for portable and wearable energy storage devices.

With the rapid development of Internet of Things and miniaturized electronics, the demand for wearable power sources with high reliability and long duty cycle promotes the exploration of wearable thermoelectric generators (TEGs). In particular, textile‐based TEGs that can perpetually convert the ubiquitous temperature gradient between human body and ambience into electrical energy have attracted intensive attention to date. These lightweight and three‐dimensional deformable TEGs comprised of fibers, filaments, yarns, or fabrics offer unique merits as wearable power source in comparison with conventional TEGs. In this review, we systematically summarize the state‐of‐the‐art strategies for textile‐based TEGs, including the structure design, fabrication, device performance, and application. Existing critical issues and future research emphasis are also discussed.

The perfect energy level overlap of 2 H 11/2 , 4 S 3/2 , and 4 F 9/2 in Er 3+ ions with those of 5 F 3 , 5 F 4 / 5 S 2 , and 5 F 5 in adjacently codoped Ho 3+ ions allows efficient interenergy transfer. Therefore, in addition to routine activators, Er 3+ or Ho 3+ can further act as sensitizers to transfer the upconverted energy to nearby Ho 3+ or Er 3+ , resulting in enhanced upconversion luminescence due to the emission overlap. Proper codoping of Er 3+ /Ho 3+ or Ho 3+ /Er 3+ obviously elevates the maximum doping concentration (thus producing additional upconverted photons) to a level higher than that causing luminescence quenching and significantly enhances upconversion emissions compared with those of singly Er 3+ or Ho 3+ -doped host materials. Indeed, the so-far strongest red upconversion emission under 1532 nm excitation was obtained in LiYF 4 :Er/Ho@LiYF 4 nanoparticles and Ho 3+ -sensitized Er 3+ upconversion emissions excited by 1150 nm laser was simultaneously discovered. With great enhancement compared with that of singly Ho 3+ doped counterparts, this work demonstrates the generality and rationality of our design strategy.

In recent years, the thermoelectric properties of inorganic/polymer composites have been markedly improved. However, the enhancement mechanism in inorganic/polymer composites is still far from clear. In this work, we fabricate a novel type of thermoelectric composite by mixing high-mobility poly­(3,4-ethylenedioxythiophene) nanowire with tellurium nanowire and investigate the thermoelectric properties by varying the loading of tellurium nanowires and the underlying enhancement mechanism. We find that the addition of tellurium nanowire can enhance the thermoelectric power factor of inorganic/polymer nanowire composites by ∼40%. We, for the first time, quantitatively interpret the effect of energy filtering on thermoelectric power factor enhancement in polymer inorganic composites by employing the hopping transport theory. In contrast to the series/parallel connected model, we determine that the energy filtering is more feasible to physically explain the thermoelectric enhancement. It can numerically explain the enhancement in Seebeck coefficient, electrical conductivity, and power factor. We believe it is assigned to the high carrier mobility in nanowire composites and proper energy barrier at polymer/inorganic interfaces.