The development and enrichment of organic materials with narrowband emission in longer wavelength region beyond 515 nm still remains a great challenge. Herein, a significant synthetic methodology for narrowband emission materials has been proposed to functionalize multiple resonance (MR) skeleton and generate a universal building block, namely, the key intermediate DtCzB-Bpin, which can be utilized to construct multifarious thermally activated delayed fluorescence (TADF) materials with high color purity through a simple one-step Suzuki coupling reaction. Based on the unique synthetic strategy, a series of efficient narrowband green TADF emitters has been constructed by localized attachment of 1,3,5-triazine and pyrimidine derivativesbased acceptors onto B-N-containing MR framework with 1,3-bis(3,6-di-tert-butylcarbazol-9-yl)benzene (DtCz) as ligand. The precise modulation of acceptor is an ingenious approach for achieving bathochromic shift and narrowband emission simultaneously. The DtCzB-TPTRZ-based organic light-emitting diode (OLED) exhibits pure green emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23, 0.68), and maximum external quantum efficiency (EQE) of 30.6% as well as relatively low efficiency roll-off.

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High‐voltage LiCoO2 is an attractive cathode for ultra‐high energy lithium‐ion batteries in the 5G era. However, the practical application of LiCoO2 is largely hindered by the unstable structure under high voltage. Herein, dextran sulfate lithium (DSL) is used as a versatile binder to improve the cycling stability of LiCoO2 at 4.6 V. A coulombic efficiency of almost 100% and 93.4% capacity retention after 100 cycles has been achieved. The aqueous DSL binder can be evenly coated onto the surfaces of LiCoO2 particles to function as an artificial interface, significantly preventing the decomposition of electrolyte and the dissolution of Co ions. More importantly, the superior interaction between the sulfate acid groups of DSL chains and the LiCoO2 particles enhances the stability of CoO chemical bonds, further suppressing the detrimental phase transition from O3 to H1‐3 above 4.55 V. The stabilization of high‐voltage LiCoO2 through the binder is facile and enlightening to design high energy battery materials.

Generally, 6s electron and 6p electron of Bi3+ ions are located in its outermost layer; thus, luminescence properties of Bi3+ are strongly associated with the coordination environment around Bi3+. Bi3+ ions occupy different cationic positions in hosts, which may cause the movement of the emission spectrum. In order to investigate the luminescent property of Bi3+, a series of Bi3+ doped Ca5(BO3)3F species are synthesized. There are three types of Ca2+ sites in the host, which could be substituted by Bi3+. Upon the 322 nm excitation of Bi3+, a broad emission band can be observed, which is ascribed to the 1s0 → 3p1 transition of Bi3+. Meanwhile, there is the emission shift of Ca5(BO3)3­F:xBi3+, and its emission color can be altered from blue to cyan. It may result from Bi3+ occupying different positions of Ca2+ in the host, which can give rise to different degrees of a nephelauxetic effect and crystal field splitting. In order to explore the relationship between the luminescence properties of Bi3+ and the nepelauxetic effect, the value of the centroid shift (∈c) is calculated. Centroid shift (∈c) is related to the covalence and average bond length of an octahedron in which the influence of covalence is primary. The relationship between the luminescence properties of Bi3+ and the crystal field splitting is discussed. The crystal field splitting is related to the interaction between the Bi3+ species, the crystal field splitting energy (Δ), and the distortion of the crystal. Emission spectra are asymmetric; meanwhile, the emission spectra have remarkable changes at various excitation wavelengths. This proves that the broadband emission band consists of at least two emission centers. In order to assess this hypothesis, the decay curves are measured. This confirms that there are three luminescence centers in a host. On one hand, considering the effect of the centroid shift (∈c) and crystal field splitting (∈cfs), the sources of three luminescence centers are confirmed by calculating the total shift (D(A)) of the 6s6p level of Bi3+ in a host. On the other hand, the source of three luminescence centers is determined by the changing trend of the average bond length of the octahedron. In addition, the luminescence properties of Ca5(BO3)3F:Bi3+, Eu3+, are investigated as well. There is efficient energy transfer from the Bi3+ to the Eu3+ ion, and the color-tunable phosphor can be achieved by the combination of the appropriate proportion of Bi3+ and Eu3+ ions. The emission color can gradually change from cyan to red.

Metals can be strengthened by adding hard reinforcements, but such strategy usually compromises ductility and toughness. Natural nacre consists of hard and soft phases organized in a regular "brick-and-mortar" structure and exhibits a superior combination of mechanical strength and toughness, which is an attractive model for strengthening and toughening artificial composites, but such bioinspired metal matrix composite has yet to be made. Here we prepared nacre-like reduced graphene oxide (RGrO) reinforced Cu matrix composite based on a preform impregnation process, by which two-dimensional RGrO was used as "brick" and inserted into "□-and-mortar" ordered porous Cu preform (the symbol "□" means the absence of "brick"), followed by compacting. This process realized uniform dispersion and alignment of RGrO in Cu matrix simultaneously. The RGrO-and-Cu artificial nacres exhibited simultaneous enhancement on yield strength and ductility as well as increased modulus, attributed to RGrO strengthening, effective crack deflection and a possible combined failure mode of RGrO. The artificial nacres also showed significantly higher strengthening efficiency than other conventional Cu matrix composites, which might be related to the alignment of RGrO.