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New oxygen and pressure sensitive paints (PSPs) with four-arm polymeric structures were prepared by using a kind of controlled living polymerizations – atom transfer radical polymerization (ATRP). The polymers composing of poly(isobutyl methacrylate)-co-poly(trifluoroethyl methacrylate)s (PolyIBMA-co-PolyTFEM)s act as the matrices for the platinum porphyrin-based phosphorescence probes, which were copolymerized in the matrices. The polymers were characterized by using 1H NMR, 19F NMR, and GPC to demonstrate their successful preparation. The influence of polymer structures on sensing activity including the sensitivity and response time to oxygen and/or pressure was investigated. Results showed that copolymers with suitable compositions (herein P3) can have highest sensitivity. Polymer structure’s influence on response time to oxygen was also investigated. For increasing the polymer’s surface area for further improving sensing sensitivity, electrospinning method was used for preparing films with micro-spherical or fibrous structures. The morphologies of electrospinning coated films were observed by SEM. Results showed that electrospinning coated films can respond much better to oxygen and pressure than their corresponding sprayed plates. This is the first time to apply the controlled living polymerization approach to prepare PSPs with multi-arm structures, which will broaden the PSP functional materials’ design strategy.

Polymeric microfibers, particularly the fluorinated copolymers’ fibers, are promising functional materials for photoelectric devices, sensing, and energy storage due to their various surface characteristics. However, to obtain the high fluorine content copolymer-based fibers with considerable uniformity is likely to be especially challenging, which seriously debilitates their applications in sensor devices. Herein, for the first time, we presented a high fluorine content platinum porphyrin-grafted poly(isobutyl methacrylate-co-dodecafluoroheptyl methacrylate) copolymers (PtTFPP-p(IBM-co-DFHMA)) microfibrous thin-films used as optical oxygen sensors. The porous thin-film frameworks were formed of uniform microfibers, which afforded an exceptional improvement in sensitivity and exhibited 584% higher sensitivity than the solid sensing film owing to the large specific surface area, porous structures and oxygen diffusion enhancement by fluorine elements. Additionally, the remarkable emission intensity-changing characteristic of the microfiber sensing film under various air pressures facilitates convenient visualization of pressure distributions on film surface. The characteristics are particularly important for the computational fluid dynamics simulations in various sensing fields such as unsteady flow visualization and unsteady pressure measurements, etc. Owing to its attractive advantages and versatile performance, fluorine-containing copolymers fibers are expected to provide a new strategy for the rational design of high performance gas sensor devices.

The hybrid pixel detector Timepix3 allows the measurement of the time and energy deposition of an event simultaneously in each 55 $\mu$m pixel, which makes Timepix3 a promising approach for a compact Compton camera. However, the angular resolution of Compton camera based on this kind of detector with high pixel density is usually degraded in imaging of MeV gamma-ray sources, because the diffusion of energetic Compton electron or photoelectron could trigger many pixels and lead to an inaccurate measurement of interaction position. In this study, an electron track algorithm is used to reconstruct the electron track and determine the interaction point. An demonstrative experiment was carried out, showing that the effect of this algorithm was significant. The angular resolution measures of a single layer Compton camera based on Timepix3 was enhanced to 12 degrees (FWHM) in imaging of a Co-60 gamma source., Comment: final manuscript, 27 pages, 13 figures, published on NIM-A

The excellent electrochemical performance of indium sulfide (In2S3) in lithium ion batteries (LIBs) and sodium ion batteries (SIBs) prompted us to explore its energy storage mechanism in potassium ion batteries (PIBs). In this work, In2S3/C nanofibers are successfully synthesized by simple electrospinning and subsequent vulcanization. In K half cells, compared to commercial In2S3 electrodes, In2S3/C nanofibers as anode materials for PIBs show outstanding electrochemical performance, which can deliver reversible capacities of 397.6 (25), 366.2 (50), 335.2 (100), 307.8 (200), 260.4 (500) and 212.2 mAh g−1 (1000 mA g−1), respectively. In K full cells, In2S3/C nanofibers can also show good potassium storage performance and can light up 15 light emitting diodes (LEDs). The superb electrochemical performance of In2S3/C nanofibers is due to the in-situ composite with self-nitrogen-doped carbon matrix and the nanoization of In2S3 particles, which buffers the volume effect and improves the conductivity of the material during the potassium storage process. In addition, the mechanism of potassium storage of In2S3/C nanofibers was systematically studied by cyclic voltammetry (CV), ex-situ XRD, TEM and XPS methods. The mechanism of In2S3 for K-ion storage can be described as the conversion reaction: In2S3 + 6K+ + 6e− ⇌ In + 3K2S.

Both antimony selenide and antimony are promising anode materials for lithium-ion batteries. However, owing to the influence of the poor electronic conductivity of Sb2Se3 and the large volume expansion of the two materials during the lithiation process, their electrochemical performance is limited and the practical application is restricted. In this work, for the first time, the hierarchical Sb2Se3 and Sb particles fully encapsulated into carbon nanofibers (Sb2Se3/Sb/C nanofibers) have been in-situ synthesized by electrospinning followed by controlled annealing. Combining the advantages of high specific capacity of Sb2Se3, good electronic conductivities of Sb and C, and strong stability of C matrix, the Sb2Se3/Sb/C nanofibers electrode shows excellent lithium-storage performance. It achieves a high reversible capacity (764 mA h g−1 after 300 cycles at 0.1 A g−1), splendid ultralong cycling stability (429 mA h g−1 after 1000 cycles at 1 A g−1), and high rate capability (342 mA h g−1 at 5 A g−1). It demonstrates that Sb2Se3/Sb/C nanofibers are promising high-performance anode materials for lithium-ion batteries.

The key to the development of wearable electronic equipment lies in the design of flexible batteries, in which the electrodes with outstanding mechanical behavior are quite important. Herein, porous nitrogen-doped Sn/C fibers (P-Sn/C-N Fs) film has been successfully synthesized via simple electrospinning and subsequent calcination process in which folic acid and polymethylmethacrylate (PMMA) play the role of introducing nitrogen and forming pores, respectively. The introduction of nitrogen improves the electronic conductivity of the material, and the presence of porous structure increases the specific surface area. More importantly, when the P-Sn/C-N Fs film is used directly as a free-standing electrode for lithium ion batteries, it exhibits outstanding electrochemical performance. The P-Sn/C-N Fs film exhibits a discharge capacity of 712.1 mAh g−1 at 500 mA g−1 after 500 cycles. Even at the high current density of 5 A g−1, it displays a high discharge capacity of 429.1 mAh g−1 after 1000 cycles. These findings indicate that the P-Sn/C-N Fs film has the potential to be applied as free-standing anode materials for lithium ion batteries.

Tungsten oxide thin films were deposited at room temperature under different negative bias voltages (Vb, 0 to −500 V) by DC reactive magnetron sputtering, and then the as-deposited films were annealed at 500 °C in air atmosphere. The crystal structure, surface morphology, chemical composition and transmittance of the tungsten oxide thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and UV–vis spectrophotometer. The XRD analysis reveals that the tungsten oxide films deposited at different negative bias voltages present a partly crystallized amorphous structure. All the films transfer from amorphous to crystalline (monoclinic + hexagonal) after annealing 3 h at 500 °C. Furthermore, the crystallized tungsten oxide films show different preferred orientation. The morphology of the tungsten oxide films deposited at different negative bias voltages is consisted of fine nanoscale grains. The grains grow up and conjunct with each other after annealing. The tungsten oxide films deposited at higher negative bias voltages after annealing show non-uniform special morphology. Substoichiometric tungsten oxide films were formed as evidenced by XPS spectra of W4f and O1s. As a result, semi-transparent films were obtained in the visible range for all films deposited at different negative bias voltages.