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Highlights: [•] We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. [•] By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. [•] By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500nm. [•] The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. [Copyright &y& Elsevier]

Conductive hydrogels have attracted tremendous attention for the next-generation electronic/energy/robotic application owing to their excellent mechanical and electrical properties, including stretchability, high conductivity, and stability. How to simultaneously realize their highly transparent, self-healing, antifreezing/antidrying, biocompatible and highly conductive features through a simple approach is still a challenge. Herein, the stretchable freezing-tolerant triboelectric nanogenerator (TENG) and strain sensor have been developed based on a transparent, long-term stable, and highly conductive gelatin/NaCl organohydrogel (GNOH), which is prepared via a facile immersion strategy in a glycerol/water binary solvent. The GNOH demonstrates superior merits of strain (300%), transparency (85%), high conductivity (1.6 S/m), freezing tolerance (−20 ℃), self-healing capability (91%), and environment stability (over 30 days). Furthermore, the wearable strain sensors enable the detecting, quantifying, and monitoring of human activities with high sensitivity of about 2.5 (strain of 0–200%). Meanwhile, the fabricated TENG in single-electrode mode can achieve excellent electrical outputs to power portable electronics when efficiently harvesting biomechanical energies, even at harsh cold temperature (−20 ℃). Additionally, a flexible self-powered calculator based on the arrayed TENG as touch panel is also explored for human-machine interaction (HMI). This study paves the way for potential applications in wearable electronics, healthcare monitoring, biomechanical energy harvesting and HMI. [Display omitted] Stretchable freezing-tolerant triboelectric nanogenerator (TENG) and strain sensor has been proposed based on transparent, long-term stable, and highly conductive gelatin/NaCl-based organohydrogel (GNOH). The GNOH demonstrates excellent characteristics of mechanical stretchability, freezing tolerance, long-term ambient stability, and self-healing capability. The fabricated TENG and wearable strain sensor enable the real-time monitoring of human motion and harvesting of biomechanical energy. • Organohydrogel demonstrates superior merits of strain (300%), transparency (85%), high conductivity, and freezing tolerance. • The wearable strain sensors enable the detecting, quantifying, and monitoring of human activities. • The fabricated AG-TENG at −20 ℃ can achieve excellent electrical outputs when harvesting biomechanical energy. • A flexible self-powered calculator based on the arrayed TENG as touch panel is also explored for human-machine interaction. [ABSTRACT FROM AUTHOR]

As worldwide forest fire frequently causes a serious threat to forest resources and global climate change, novel early forest fire monitoring and detection technologies are urgently required to explore. Herein, a self-powered forest fire alarm system (FFAS) is proposed by coupling thermosensitive effect and triboelectric effect as an aim of effective forest fire monitoring and detecting. The FFAS is fabricated as a self-powered early forest fire monitoring and detection system by connecting a spherical free-standingmode triboelectric nanogenerator (S-TENG) as power source with polydopamine-modified graphene oxide (P-GO) as thermosensitive sensor and commercial LEDs as alarm. When encountering an open fire or abnormal high temperature the thermosensitive sensor based on P-GO can be in-situ thermally reduced, inducing an obvious transition in electrical resistance. Thus, the output voltage of S-TENG can be tuned by the impedance matching effect between special output characteristics of TENG and working status of thermosensitive sensor, and then can directly light up the LEDs as alarm. Furthermore, the FFAS achieves a low temperature response (160 °C), rapid response time (~3 s), and especially no external power supply. Consequently, the FFAS based on impedance matching effect between TENG and thermosensitive sensor would provide a real-time, rapidly responsive, and self-powered monitoring strategy for the early forest fire warning and detection. A self-powered forest fire alarm system (FFAS) was proposed based on impedance matching effect between TENG and thermosensitive sensor. When encountering an open fire the P-GO thermosensitive sensor can be reduced to decrease dramatically the electrical resistance. Thus, the output voltage of TENG driven by natural wind can be tuned to directly light up the LEDs as alarm. The response time (3 s) for the resistance change is consistent with that of the output voltage profile in open fire. The self-powered FFAS based on TENG would provide a novel strategy for a real-time, rapid response, and self-powered early forest fire monitoring and detection. Image 1 • A self-powered forest fire alarm system is demonstrated based on an impedance matching effect between TENG and P-GO sensor. • The electric resistance of P-GO was decreased dramatically when encountering open fire or high temperature more than 160 °C. • The response time (3 s) of resistance change is consistent with that of output voltage performance of TENG under open fire. • The low temperature response (160 °C) and rapid response time (3 s) endow the self-powered FFAS for forest fire monitoring. [ABSTRACT FROM AUTHOR]

In recent years, copper-based halide scintillators have attracted tremendous attention due to their excellent luminescent properties and low manufacturing costs. Herein, a high-performance and low-cost Cs 5 Cu 3 Cl 6 I 2 scintillator is prepared by simple mechanical grinding. The mixed-halide Cs 5 Cu 3 Cl 6 I 2 phosphor exhibits a blue emission centered at 475 nm with a large stokes shift, originating from the self-trapped exciton emission of Cu sites. The photoluminescence quantum yield (PLQY) of Cs 5 Cu 3 Cl 6 I 2 can be increased to 88.4% from 20.4% by the efficient suppression of the anion vacancy defects. In addition, the Cs 5 Cu 3 Cl 6 I 2 scintillator shows a high steady-state X-ray to light conversion efficiency of about 57000 photons/MeV, good X-ray linear response, and low detection limit of 71.9 nGy air /s. The X-ray imaging results based on the Cs 5 Cu 3 Cl 6 I 2 scintillator screen display a high spatial resolution of 9.0 line-pairs per millimeter (lp/mm). Furthermore, Cs 5 Cu 3 Cl 6 I 2 exhibits good radiation stability under a total dose of 113.58 Gy air. Overall, the Cs 5 Cu 3 Cl 6 I 2 scintillator prepared by mechanical grinding method has the advantages of low cost, high efficiency, and good radiation resistance, suggesting its huge potential in X-ray detection and imaging. [ABSTRACT FROM AUTHOR]

The rapid development of industrialization and urbanization has led to haze in Beijing that has garnered world attention. For the first time, we studied the luminescence properties of individual haze aerosol particles by using a scanning electron microscope (SEM) coupled with a cathodoluminescence (CL) spectrometer. CL analysis has rarely been reported for haze particles, however, we found that many haze particles showed varied luminescence characteristics. Many types of mineral dusts showed strong CL emission in the visible light wavelengths. Nitrogen-rich secondary particles had a strong CL emission in the UV wavelengths. Anthropogenic particles such as fly ash and Fe-rich, Ti-rich, and carbonaceous materials had much weaker CL responses. The mixture of mineral dusts and other species showed lower CL intensity and widened CL spectra, which continuously covered the UV-VIS-IR portion of the spectrum and which contrasted with the CL emissions of original mineral dusts and pure secondary salts. The sensitivity of CL spectra with respect to tiny changes in components, impurity, and valences enabled the CL spectroscopy to provide a unique perspective with which to analyze highly complicated mixtures of haze particles. [ABSTRACT FROM AUTHOR]

Investigating the hygroscopic behavior of haze aerosol particles is essential for understanding their physicochemical properties and their impacts on regional weather and visibility. An environmental scanning electron microscope equipped with a home-made transmission-scattering electron imaging setup and an energy dispersive spectrometer was used for in-situ observations of pure water-soluble (WS) salts and Beijing haze particles. This imaging setup showed obvious advantages for improving the resolution and acquiring internal information of mixed particles in hydrated environments. We measured the deliquescence relative humidity of pure NaCl, NH 4 NO 3 , and (NH 4 ) 2 SO 4 by deliquescence–crystallization processes with an accuracy of up to 0.3% RH. The mixed haze particles showed hygroscopic activation like water uptake and morphological changes when they included WS components such as nitrates, sulfates, halides, ammoniums, and alkali metal salts. In addition, the hygroscopic behavior provides complementary information for analyzing possible phases in mixed haze particles. [ABSTRACT FROM AUTHOR]