High‐quality InP/ZnS core–shell nanocrystals with luminescence tunable over the entire visible spectrum have been achieved by a facile one‐pot solvothermal method. These nanocrystals exhibit high quantum yields (above 60%), wide emission spectrum tunability and excellent photostability. The FWHM can be as narrow as 38 nm, which is close to that of CdSe nanocrystals. Also, making use of these nanocrystals, we further demonstrated a cadmium‐free white QD‐LED with a high color rendering index of 91. The high‐performance of the resulting InP/ZnS NCs coupled with their low intrinsic toxicity may further promote industrial applications of these NC emitters.
Diamond nanoparticles synthesized by the detonation of explosives were used as an additive in paraffin oil. The tribological properties of the two-phase lubricant of paraffin oil and diamond nanoparticles were investigated. The results show that, under boundary lubricating conditions, this kind of two-phase lubricant possesses excellent load-carrying capacity, anti-wear and friction-reduction properties. The ball-bearing effect of diamond nanoparticles existed between the rubbing faces, the surface polishing and the increase in surface hardness effects of the diamond nanoparticles are the main reasons for the reduction in wear and friction.
Large carbon networks featuring hierarchical pores and atomically dispersed metal sites (ADMSs) are ideal materials for energy storage and conversion due to the spatially continuous conductive networks and highly active ADMSs. However, it is a challenge to synthesize such ADMS‐decorated carbon networks. Here, an innovative fusion‐foaming methodology is presented in which energetic metal–organic framework (EMOF) nanoparticles are puffed up to submillimeter‐scaled ADMS‐decorated carbon networks via a one‐step pyrolysis. Their extraordinary catalytic performance towards oxygen reduction reaction verifies the practicability of this synthetic approach. Moreover, this approach can be readily applicable to a wide range of unexplored EMOFs, expanding scopes for future materials design.
Electrochemical nitrogen reduction reaction (NRR) under room temperature and ambient pressure is a promising energy‐ and environmental‐friendly method for ammonia synthesis, which currently highly relies on the energy‐consuming Haber‐Bosch process with enormous CO2 emissions. This study reports the synthesis of a noble‐metal‐free CoP hollow nanocage (CoP HNC) catalyst from a metal‐organic framework precursor through a layered‐double‐hydroxide intermediate, and the use as the cathode for electrochemical NRR. The 3D hierarchical nanoparticle–nanosheet–nanocage structure provides rich surface active sites for nitrogen adsorption and reduction. When applied for NRR, CoP HNC exhibits exciting performance with high Faraday efficiency at low overpotentials (7.36% at 0 V vs reversible hydrogen electrode [RHE]), and the ammonia yield rate increases exponentially at more negative potential, reaching 10.78 µg h−1 at −0.4 V (vs RHE) with good selectivity (no hydrazine produced) under ambient conditions. This noble‐metal‐free electrocatalyst with promising performance demonstrates the unique potential of transition metal and their compounds in the field of NRR, providing new perspectives to rational catalyst design and mechanism study.
Abstract. The refractive indices, absorption coefficients, and complex dielectric constants of paraffin-embedded brain glioma and normal brain tissues have been measured by a terahertz time-domain spectroscopy (THz-TDS) system in the 0.2-to 2.0-THz range. The spectral differences between gliomas and normal brain tissues were obtained. Compared with normal brain tissue, our results indicate that paraffin-embedded brain gliomas have a higher refractive index, absorption coefficient, and dielectric constant. Based on these results, the best THz frequencies for different methods of paraffin-embedded brain glioma imaging, such as intensity imaging, coherent imaging with continuum THz sources, and THz pulsed imaging with short-pulsed THz sources, are analyzed.
n - Zn O ∕ Si O x ∕ n - Si and n-ZnO∕SiOx∕p-Si heterostructured light-emitting diodes have been fabricated using metal-organic chemical-vapor deposition for a comparison study. n-ZnO∕SiOx∕p-Si heterostructures show diodelike rectifying current-voltage characteristic with low breakdown voltage, while n-ZnO∕SiOx∕n-Si heterostructures show symmetric nonlinear current-voltage behavior due to the double Schottky barriers at the interface. Both types of diodes emit light when a positive bias applied at Si side. Ultraviolet emission at ∼390nm with an orange-emission centered at ∼600nm were observed in electroluminescence spectra of n-ZnO∕SiOx∕n-Si diodes, while whitish emission centered at ∼520nm was observed for n-ZnO∕SiOx∕p-Si diodes. The emission mechanisms were discussed.
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