结构化学最新文献

Two-dimensional (2D) lead halide perovskites have attracted tremendous attention due to their outstanding physical properties. However, the presence of toxic lead is a major problem for large-scale applications. Here, we report the synthesis, phase transition, dielectric and photoluminescence (PL) properties of a lead-free 2D Ge-based perovskite (BIM)₂GeI₄ (BIM = benzimidazolium) which experiences a phase transition at 405 K accompanied by an order-disorder change of organic spacer. Moreover, the step-like dielectric transition near the phase transition temperature makes it suitable for dielectric switching. Meanwhile, (BIM)₂GeI₄ has a direct bandgap of 2.23 eV and broadband emission from 550 to 1000 nm, implying its unique optical property for potential near-infrared lighting and displaying. This work provides a fresh example for the development of lead-free 2D Ge-based perovskite with potential applications in the fields of optoelectronics and high temperature dielectric switching.

Materials exhibiting dielectric switching response and photoluminescence (PL) are promising for sensors and information storage. In previous research, we synthesized a series of materials with red or green PL and dielectric switching capabilities by incorporating luminescent metal halides into organic ammonium compounds. However, effective modification to synthesize organic-inorganic hybrid materials with dielectric switching response and orange PL continues to be a challenge in the respective fields. Orange PL materials are valuable for switching and sensors, and most orange light sources are derived from rare earth elements, making them harder to obtain. We have successfully synthesized two organic-inorganic hybrid materials ([CMPD]PbBr₃ (1) and [BMPD]PbBr₃ (2), CMPD = N-ClCH₂-N-methylpiperidine, BMPD = N-BrCH₂-N-methylpiperidine) that exhibit both orange PL and dielectric switching response. When Cl in compound 1 is substituted by Br in compound 2, the phase transition temperature of the compound is elevated by 45 K. These compounds exhibit captivating orange light emission when exposed to ultraviolet lamps. This research provides insights into exploring multifunctional materials with orange PL and dielectric switching response and provides proof for halogen substitution strategies to design materials with higher phase transition temperatures.

Hybrid organic-inorganic perovskites (HOIP) have attracted increasing interest in the last decade. While current research in this field focuses on metal halide HOIPs because of their excellent photovoltaic and optoelectronic properties, other hybrid perovskites are also being designed and developed for other properties. Among them, HOIPs bridged by nitrate show structural diversity and a remarkable range of physical properties. In this mini review, we summarize their structural features and rich physical properties including structural phase transitions, ferroelectric, piezoelectric, piezomagnetic and photoluminescencent properties. In addition, the challenges for improving the physical properties achieved by such materials and the space for further development of such materials are also discussed.

Chloroprene is a monomer widely used in the production of neoprene, and 1-hydroxy-2-butanone (1H2B) is one of the metabolites of chloroprene in urine, which can place a significant impact on human health by disrupting the normal structure and function of DNA. Herein, a three-dimensional Zn-based coordination polymer (1) and a two-dimensional Cd-based coordination polymer (2) were synthesized with mixed ligands of 2,5-furandicarboxylic acid (H₂FDA) and 1,2,4-triazole (Htrz) and fully characterized. 2 exhibits excellent stability and superior sensing performance for 1H2B with fast response within 15 s, good recyclability and a detection limit of 9.24 μM. In addition, 2 demonstrates good selectivity in presence of main coexisting compounds in urine. In-depth investigations of the sensing mechanism revealed that the luminescence sensing is based on the competitive absorption and photoelectron transfer processes.