(NH4)Bi2(IO3)2F5: An Unusual Ammonium-Containing Metal Iodate Fluoride Showing Strong Second Harmonic Generation Response and Thermochromic Behavior

An ammonium-containing metal iodate fluoride compound, (NH₄)Bi₂(IO₃)₂F₅, featuring a two-dimensional double-layered framework constructed by [BiO₂F₅]⁶⁻ and [BiO₄F₄]⁹⁻ polyhedra, as well as [IO₃]⁻ groups, was successfully synthesized. The well-ordered alignment of these SHG-active units leads to an extraordinary strong SHG response of 9.2 times that of KDP. Moreover, this compound possesses a large birefringence (Δn=0.0690 at 589.3 nm), a wide energy band gap (E_g=3.88 eV), and a high laser damage threshold (LDT; 40.2×AgGaS₂). In particular, thermochromic behavior was observed for the first time in this type of compound. Such multifunctional crystals will expand the application of nonlinear optical materials.     

Gadolinium Pivalate Complex as a Precursor for the Synthesis of Titanium Oxo Clusters: Solvent Influence and Structural Analysis

In this text, we present researches on the synthesis of polyoxo-titanium clusters(PTCs) by the use of gadolinium pivalate precursor. During the synthesis process, we discover that solvents play an important role. When acetonitrile was used as solvent, Ti_8Gd(μ_2-O)(μ_3-O)_5(Sal)_5(OPiv)_2(μ_2-O~iPr)_3(μ-O~iPr)_8(PTC-82)(H_2Sal = salicylic acid, HOPiv = pivalic acid) was obtained. When N,N-dimethylformamide(DMF) was used as solvent under the same reaction conditions, Ti_4Gd_2(μ_3-O)_2(Sal)_4(OPiv)_4(μ_2-O~iPr)_2(μ-O~iPr)_4(DMF)2(PTC-83) was synthesized. The solid-state UV absorption spectra revealed that the dopant of lanthanide and the incorporation of salicylic acid ligands have successfully narrowed the bandgap of PTCs. In addition, they exhibited rapid and reproducible photo-responses.     

Vapor-assisted epitaxial growth of porphyrin-based MOF thin film for nonlinear optical limiting

Fabrication of metal-organic frameworks(MOFs) thin films has been an efficient way to expand their functionalities and applications. Here, we use the vapor-assisted deposition(VAD) method to epitaxially grow a porphyrin-based MOF PCN-222 film. That is, vapor source assists to deposit pre-treated precursor solution on quartz substrate to form a continuous PCN-222 film. Furthermore, utilizing the post-treated encapsulation of functional carbon-based nanoparticles, the carbon nanodots(CND)and Pt doped CND(Pt/CND) are well loaded into the pores of PCN-222 film, the size(～3.1 nm) of which is highly close to the pore size of the corresponding MOF(～3.7 nm). The Z-scan results reveal that PCN-222 film exhibits high reverse saturable absorption. In addition, encapsulation of carbon based nanodots into PCN-222 film could enhance the nonlinear optical limiting effect benefiting from the host-guest combination. This study serves to present both the available toolbox of thin film preparation and high potential for precise synthetic nanocomposite films in optical limiting devices.     

基于吸收互补有机半导体本体复合薄膜的高性能柔性光突触晶体管

采用光吸收互补的聚(3-己基噻吩)(P3HT)和引达省并二噻吩-苯并噻二唑共聚物(PIDT-BT), 通过溶液法制备了两者的本体复合异质结构有机半导体薄膜, 并研究了薄膜的表面结构和光电性质. 将PIDT-BT:P3HT复合薄膜作为一类新型光敏沟道层, 与聚电解质介电材料相结合, 制备了高性能柔性低电压光突触晶体管. 考察了不同光刺激条件对光突触晶体管性能的影响及半导体机制, 发现PIDT-BT:P3HT器件具有明显光突触特性, 并且相较于单纯PIDT-BT或P3HT器件具有更高响应的兴奋性突触后电流. 基于PIDT-BT:P3HT薄膜的光突触器件, 在绿红双色光刺激下的响应大于两种单色光分别刺激的响应之和, 表明附加光刺激可调控器件的记忆效率. 该研究为发展高性能光响应半导体薄膜及柔性低功耗光突触器件提供了新策略.     

基于分子工程的方法设计首例具有Sr2Be2B2O7 (SBBO)结构的深紫外氟碳酸盐双折射晶体AMgLi2(CO3)2F (A=K,Rb)※

分子结构设计是开发新化合物和通过原子尺度操纵优化晶体结构的一种引人注目的策略. 在这个工作中, 利用分子工程的思想, 基于SBBO结构, 成功设计并合成两个新型氟碳酸盐KMgLi₂(CO₃)₂F和RbMgLi₂(CO₃)₂F. 在两个结构中, a-b平面是由CO₃和LiO₃F阴离子基团组成的无限[Li₃C₃O₆F₃]_∞层, 进一步相邻的层通过F原子连接形成一个独特的[Li₆C₆O₁₂F₃]_∞双层. 这种结构特征对改善晶体的层状生长习性和消除晶体的多晶性有很大的帮助. 光学测试表明, 该系列晶体具有大的双折射和短的紫外截止边, 是深紫外双折射晶体良好的候选材料.