A beryllium-free deep-ultraviolet (deep-UV) nonlinear optical (NLO) material K3Ba3Li2Al4B6O20F is developed mainly by the element substitution of Be for Al and Li from Sr2Be2B2O7 that was considered as one of the most promising deep-UV NLO materials. K3Ba3Li2Al4B6O20F preserves the structural merits of Sr2Be2B2O7 and thus exhibits no layering growth tendency and possesses the optical properties required for deep-UV NLO applications, including deep-UV transparency, phase-matchability, and sufficiently large second-harmonic generation (1.5 × KH2PO4). Furthermore, it overcomes the structural instability problem of Sr2Be2B2O7, which is confirmed by the obtainment of large single crystals and phonon dispersion calculations. These attributes make it very attractive for next-generation deep-UV NLO materials. The substitution of Be for Al and Li in beryllium borates provides a new opportunity to design beryllium-free deep-UV NLO materials with good performance.

Color-stable light-emitting diodes based on quasi-2D PEA- and BA-perovskite with DMA as a co-ligand afford sky-blue (490 nm) and bluish green (499 nm) emission with a maximum luminance of 2825 and 7760 cd m−2 respectively.

It is demonstrated that, via surface treatment of CsPbBr3 perovskite quantum dots (PeQDs) by introducing small amount of organic ammonium chlorides possessing short alkyl chain (C ≤ 4) in methyl acetate in the typical purification process, the emission can be tuned from green to blue region with boosted photoluminescence quantum yield (PLQY). The Cl− mainly works on the surface of PeQDs to fill bromide vacancy, which generates a passivated mixed‐halide surface and avoids formation of defects deep within bandgap. Meanwhile, the replacement of initial long‐chain ligands with short chain ammonium moiety benefits the film PLQY. Accordingly, a standard blue emission of 461 nm with a high film PLQY of 52% is accessed and the corresponding colloidal shows a PLQY of 80% at 456 nm. This method is also proved to be a versatile tool to boost the PLQY of PeQDs by using short chain ammonium halides bearing the same X with the initial CsPbX3. A near‐unity colloidal PLQY of 97% and 98% is achieved for CsPbBr3 and CsPbI3 respectively. Quantum dots light‐emitting diode (QLED) with treated CsPbBr3 affords a standard blue electroluminescence of 459 nm and a maximum external quantum efficiency of 0.3%.

A novel mixed-anion phosphate, KMg 6 (P 2 O 7) 2 P 3 O 10 , has been synthesized by spontaneous crystallization technique with K 2 O-P 2 O 5-Li 2 O as a flux. Single-crystal X-ray analysis reveals that KMg 6 (P 2 O 7) 2 P 3 O 10 features two kinds of isolated anions, [P 2 O 7 ] dimers and [P 3 O 10 ] trimers. Such coexisting of two distinct anions in one polyphosphate, which has somewhat conflict with Pauling's parsimony () rule, is very rare in alkali metal and alkali-earth metal phosphates. This finding enriches the structural chemistry of phosphates and provides new perspective on the design of multiple anions materials. The thermal stability and a.c. conductivity of KMg 6 (P 2 O 7) 2 P 3 O 10 are also discussed in this paper.

Solid-state phase transition materials with a controllable dielectric response are of great interest owing to their technological importance. In the present work, a new molecular electric-ordered compound, dibenzylammonium trichloroacetate (compound 1), showing switchable and tunable dielectric properties, has been successfully synthesized and grown as bulk crystals. It is found that 1 undergoes a reversible solid-to-solid phase transition at 329 K (T c ), which was confirmed by differential scanning calorimetry (DSC), dielectric measurements and variable-temperature powder X-ray diffraction. Structural analyses reveal that intermolecular N-H⋯O hydrogen bonds connect the functional groups together and form a chain-like supramolecular architecture along the a-axis. Further, variable-temperature single-crystal X-ray diffraction discloses the order-disorder feature of its structural change, which is mainly induced by the disordering of trichloroacetate anions upon gradual heating. Moreover, the dielectric constants of 1 display a step-like anomaly around T c , suggesting that its dielectric responses could be switched or even tuned by external temperature. It is believed that this finding might provide a possible candidate with controllable dielectric performance for potential application.

Confining Li metal in a three-dimensional (3D) matrix has been proven effective in improving the Li-metal anodes; however, in most studies, the loading of Li in the 3D matrix is far excessive, resulting in a dense bulk Li-metal anode with a low Liutilization rate, forfeiting the effect of the 3D matrix. Here, we show that limiting the loading of Li metal within an interfacemodified 3D carbon matrix not only increases the Li-utilization rate but also improves the electrochemical performance of the Li-metal anode. We use lithiophilic Fe 2 O 3 granules anchored on a 3D carbon fiber scaffold to guide molten Li dispersion onto the fibers with controlled Li loading. Limiting Li loading maximizes the interface lithiophilic effect of the Fe 2 O 3 granules while preserving sufficient space for electrolyte infusion, collectively ensuring uniform Li deposition and fast Li + transport kinetics. The Li anode with limited Li dosage achieves remarkably improved Li-anode performances, including long lifespan, low voltage polarization, and low electrochemical resistance in both the symmetric cells and full cells. The improved electrochemical performance of the limited Li anode substantiates the importance to reduce Li loading from a fresh perspective and provides an avenue for building practical Limetal batteries.

Preparation of porous carbon nanofibrous membranes with excellent flexibilities and high Na ion storage capabilities to satisfy the demand of wearable energy storage devices remains challenging. Herein, a continuous and flexible porous carbon nanofibrous membrane is developed as anode material for sodium‐ion batteries by electrospinning a mixture of polyacrylonitrile (PAN) and ultrafine zeolitic imidazolate framework (ZIF‐8) nanoparticles, followed by carbonization at 1200 °C. The intrinsic porous crystal structure of ZIF‐8 and their decomposition/volatilization at high temperature assist the generation of hierarchical micro‐meso pores that are homogeneously dispersed along the nanofibers, resulting in the good flexibility and excellent Na ion storage performance. Through controlling the ZIF‐8 content at 45%, the flexible anode enables a superior Na storage capacity of 418 mA h g−1 at 0.1 A g−1 with a remarkable plateau capacity of 278 mA h g−1. The superhigh plateau capacity could be credited to the large amounts of isolated closed micro‐meso pores, implying an adsorption‐filling sodium‐ion storage mechanism. These findings provide some inspiration for the design and construction of advanced porous carbon anode materials for flexible sodium‐ion batteries.

K3Ba3Li2Al4B6 O20F is prepared by solid state reaction of a stoichiometric mixture of K2CO3, BaCO3, Li2CO3, Al2O3, LiF, and H3BO3 (1.