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In this paper, we explore the asymmetry observed between the effects of photon–phonon coupling (nested-dressing) and a crystal field (CF) on the fine structure of fluorescence (FL) and spontaneous four-wave mixing (SFWM) in Eu3+: BiPO4 and Eu3+: NaYF4. The competition between the CF and the strong photon–phonon dressing leads to dynamic splitting in two directions. The CF leads to static splitting in one direction under weak phonon dressing. The evolution from strong dressing to weak dressing results in spectral asymmetry. This spectral asymmetry includes out-of-phase FL and in-phase SFWM. Further, the large ratio between the dressing Rabi frequency and the de-phase rate leads to strong FL and SFWM asymmetry due to photon–phonon constructive dressing. Moreover, the experimental results suggest the analogy of a spectra asymmetry router with a channel equalization ratio of 96.6%. [ABSTRACT FROM AUTHOR]

Oxide solid electrolytes are attractive for the implementation of solid‐state Li‐ion batteries. However, constrained by the large ion‐transport hindrance inside the densely packed lattice, their Li‐ion conductivity can hardly reach the level of liquid electrolytes. A strategy of introducing confined water into the lattice paves a new way for enhancing the Li‐ion transport, which has been reported in the previous studies. To further verify the universality of this strategy and unravel the facilitation mechanism, here this work establishes an ideal model using Li‐H‐Cl‐O quaternary compounds with a wide electrochemical stability window. As a major kind of confined water, the content and type of ─OH groups are crucial parameters affecting the Li‐ion conductivity. Through a controllable dehydration technique, the hydrogen‐bonded ─OH groups can be mostly removed, leaving the free ─OH groups in lattice, which is beneficial to the increase of free volume and acceleration of rotation response. The 1–2 orders of magnitude enhancement of Li‐ion conductivity ensures full cells good rate and cycling performance. This work not only addresses the controversy in Li‐H‐Cl‐O about the hydrogen effect on Li‐ion transport, but also provides detailed theoretical insights for the rational design of solid electrolytes. [ABSTRACT FROM AUTHOR]

Nitrogen oxide (NO2) pollution mainly comes from automobile exhaust and industrial production. It has drawn much attention in recent years, however, selectivity and sensitivity still need to be improved for metal oxide gas sensors. In this paper, a gas-sensitive material with a nanoparticle-nanorod hierarchical structure are designed to improve the receptor function of the NO2 gas sensor. ZIF-8 layer is in situ coated on the surface of ZnO nanorods. The ZnO nanorod as a central supporting backbone, and ZnO nanocrystalline derived from ZIF-8 attached to ZnO nanorods could adsorb more NO2 molecules. The sensing experiments demonstrate that ZnO nanorods decorated with ZIF-8 derived nanoparticles exhibited better selectivity and sensitivity of about 16.3 for 1 ppm NO2 at 200 °C than pure ZnO nanorods. The selectivity and moisture resistance are investigated. The desirable NO2 sensing mechanism is investigated in detail. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) is the major reason for acid rain and respiratory illness in humans. Therefore, rapid, portable, and effective detection of NO2 is essential. Herein, a novel and simple method to construct a ZnO-SnO2 heterojunction is fabricated by pyrolysis of bimetallic metal organic frameworks. The sensitivity of ZnO-SnO2 heterojunction towards 0.2 ppm NO2 under 180 °C is 37, which is 3 times that of pure ZnO and SnO2. The construction of heterojunction speeds up the response-recovery process, and this kind of material exhibits lower detection limit. The construction of heterojunction can significantly improve the NO2 sensitivity. The selectivity, stability, and moisture resistance of ZnO-SnO2 heterojunction are carried out. This could enable the realization of highly selective and sensitive portable detection of NO2. [ABSTRACT FROM AUTHOR]