结构化学最新文献

Zero-dimensional (0D) hybrid metal halides are considered as promising light-emitting materials due to their unique broadband emission from self-trapped excitons (STEs). Despite substantial progress in the development of these materials, the photoluminescence quantum yields (PLQY) of hybrid Sb–Br analogs have not fully realized the capabilities of these materials, necessitating a better fundamental understanding of the structure-property relationship. Here, we have achieved a pressure-induced emission in 0D (EATMP)SbBr₅ (EATMP = (2-aminoethyl)trimethylphosphanium) and the underlying mechanisms are investigated using in situ experimental characterization and first-principles calculations. The pressure-induced reduction in the overlap between the STE states and ground states (GSs) results in the suppression of phonon-assisted non-radiative decay. The photoluminescence (PL) evolution is systematically demonstrated to be controlled by the pressure-regulated exciton-phonon coupling, which can be quantified using Huang-Rhys factor S. Through detailed studies of the S-PLQY relation in a series of 0D hybrid antimony halides, we establish a quantitative structure-property relationship that regulating S value toward 21 leads to the optimized emission. This work not only sheds light on pressure-induced emission in 0D hybrid metal halides but also provides valuable insights into the design principles for enhancing the PLQY in this class of materials.

The sp² carbon-conjugated covalent organic frameworks (COFs) with fully π-conjugated lattice and high chemical stability are promising heterogeneous photocatalysts. Herein, we report the design and synthesis of a novel palladium (Pd) porphyrin-based sp² carbon-conjugated COF (PdPor-sp²c-COF) with an eclipsed AA stacking 2D structure. Interestingly, PdPor-sp²c-COF showed high crystallinity, good chemical stability, and a broad absorption of visible light. Moreover, compared to our previously reported metal-free Por-sp²c-COF, PdPor-sp²c-COF displays an improved photocatalytic performance in the selective aerobic oxidation of sulfides under green light irradiation. The systematic mechanistic studies testified that the enhanced photocatalytic activity can be ascribed to promoting energy transfer pathway over PdPor-sp²c-COF. Our study clearly demonstrates that it is favorable to promote the energy transfer pathway in sp² carbon-conjugated COFs by using metalloporphyrin-based molecular building blocks. This work will inspire us to design and synthesize novel photocatalysts based on COFs for the selective aerobic oxidation.

Lithium-sulfur (Li–S) batteries are one of the promising energy storage systems. However, rapid capacity attenuation caused by shuttle effect of soluble polysulfides is a major challenge in practical application. The separator modification is one complementary countermeasure besides the construction of sulfur host materials in cathode. MXene is one type of outstanding candidates for promoting redox kinetics of sulfur species. Herein, recent advances of MXene-based materials as separator modifiers are summarized. The importance of high conductivity and catalytic effects in promoting catalytic conversion of polysulfides and suppressing shuttle effect of polysulfides has been highlighted, and the superiority of MXene for improving reversible capacity and cycling stability has been demonstrated. New strategies for the design of MXene-based separator modifiers are proposed to improve energy density and lifetime. The review provides new perspectives for future development of high-performance Li–S batteries.