Efficient and Stable Thin-Film Luminescent Solar Concentrators Enabled by Near-Infrared Emission Perovskite Nanocrystals

A novel triphenylphosphine (TPP) treatment strategy was developed to prepare the near-infrared emission CsPbI₃ nanocrystal (NC)-polymer composite thin-film luminescent solar concentrators (LSCs) featuring high absolute photoluminescence quantum yield (PLQY), low reabsorption, and high stability. The PL emission of the LSCs is centered at about 700 nm with 99.4±0.4 % PLQY and narrow full width at half maximum (FWHM) of 75 meV (30 nm). Compared with LSCs prepared with classic CsPbI₃ NCs, the stability of the LSCs after TPP treatments has been greatly improved, even after long-term (30 days) immersion in water and strong mercury-lamp irradiation (50 mW cm⁻²). Owing to the presence of lone-pair electrons on the phosphorus atom, TPP is also used as a photoinitiator, with higher efficiency than other common photoinitiators. Large-area (ca. 75 cm²) infrared LSCs were achieved with a high optical conversion efficiency of 3.1 % at a geometric factor of 10.     

Solvo-thermal Preparation and Characterization of Two CdII Coordination Polymers Constructed From 2,6-(1,2,4-Triazole-4-yl)pyridine and 5-R-Isophthalic Acid (R = Nitro,Sulfo)

Under the solvo-thermal conditions, two novel Cd^II mixed-ligand coordination materials with 2,6-(1,2,4-triazole-4-yl)pyridine(L₁) and aromatic poly-carboxylic acid co-ligands such as 5-R-isophthalic acid (R = nitro, sulfo), namely [Cd(L₁)(NO₂-BDC)(H₂O)₂] · 2H₂O ( 1 ) and [Cd(L₁)(HSIP)(H₂O)] · 4H₂O ( 2 ) (NO₂-H₂BDC = 5-nitroisophthalic acid, H₃SIP = 5-sulfobenzene -isophthalic acid) were successfully prepared. These Cd^II mixed-ligand coordination polymers 1 – 2 have been measured by crystal X-ray analysis, FT-IR spectra and powder X-ray diffraction analyses. In 1 , these seven-coordinate Cd^II atoms (Cd1) are inter-linked by didentate 5-nitroisophthalic acid ligands forming 1D chain structures. In 2 , these L₁ and partially de-pronated HSIP^2– are inter-linked by central Cd^II centers and are arranged into the unique 2D micro-porous metal-organic framework of 2 . Side view of 2 , it is noted that numerous oxygen atoms of un-coordinated carboxylate groups and coordinated SO₃ groups protrude out and decorate the 2D framework of 2 . PXRD patterns of 1 and 2 sample is tested, which is consistent with the simulated PXRD diffraction pattern. Photoluminescence studies show that 2 is highly selective and sensitive to trace elements of Eu³⁺ with excellent K_sv value (7.86 × 10⁴ m ^–1) and low detection limit (5.56 × 10^–2 mM), which also provides a convenient method and platform for real-time detection of Eu³⁺.     

Thermoelectric Properties of Nano-grained Mooihoekite Cu9Fe9S16

Cu-Fe-S-based compounds gain the interest from thermoelectric community because all the consisting elements, Cu, Fe, and S, are non-toxic and earth-abundant. Comparing with CuFeS₂ and Cu₅FeS₄, the investigation on Cu₉Fe₉S₁₆ is very rare. In this work, a series of Cu_9–xFe_9+xS₁₆ samples were fabricated by means of melting-annealing process. Their phase composition, microstructure, electrical and thermal transport properties were systematically investigated. X-ray measurement confirms that all samples are phase pure. Transmission electron microscopy characterization indicates that the fabricated Cu₉Fe₉S₁₆ has a natural nanostructure. Cu₉Fe₉S₁₆ shows semiconducting-like electrical transport behavior and intrinsically low lattice thermal conductivity. Beyond the numerous boundaries between nanosized grains, the existence of low-frequency optical phonons is also responsible for the intrinsically low lattice thermal conductivity. Doping Fe at the Cu-sites in Cu₉Fe₉S₁₆ significantly alters the electrical transport properties by introducing extra carriers. A peak dimensionless figure of merit zT value of 0.21 is obtained at 800 K for pure Cu₉Fe₉S₁₆, which is comparable with that for CuFeS₂.     

Indandione-Terminated Quinoids: Facile Synthesis by Alkoxide-Mediated Rearrangement Reaction and Semiconducting Properties

A series of 1,3-indandione-terminated π-conjugated quinoids were synthesized by alkoxide-mediated rearrangement reaction of the respective alkene precursors, followed by air oxidation. This new protocol allows access to quinoidal compounds with variable termini and cores. The resulting quinoids all show LUMO levels below −4.0 eV and molar extinction coefficients above 10⁵ L mol⁻¹ cm⁻¹. The optoelectronic properties of these compounds can be regulated by tuning the central cores as well as the aryl termini ascribed to the delocalized frontier molecular orbitals over the entire molecular skeleton involving aryl termini. n-Channel organic thin-film transistors with electron mobility of up to 0.38 cm² V⁻¹ s⁻¹ were fabricated, showing the potential of this new class of quinoids as organic semiconductors.     

Toughening a Self-Healable Supramolecular Polymer by Ionic Cluster-Enhanced Iron-Carboxylate Complexes

Supramolecular polymers that can heal themselves automatically usually exhibit weakness in mechanical toughness and stretchability. Here we exploit a toughening strategy for a dynamic dry supramolecular network by introducing ionic cluster-enhanced iron-carboxylate complexes. The resulting dry supramolecular network simultaneous exhibits tough mechanical strength, high stretchability, self-healing ability, and processability at room temperature. The excellent performance of these distinct supramolecular polymers is attributed to the hierarchical existence of four types of dynamic combinations in the high-density dry network, including dynamic covalent disulfide bonds, noncovalent H-bonds, iron-carboxylate complexes and ionic clustering interactions. The extremely facile preparation method of this self-healing polymer offers prospects for high-performance low-cost material among others for coatings and wearable devices.     

Filling a Gap: The Coordinatively Saturated Group 4 Carbonyl Complexes TM(CO)8 (TM=Zr,Hf) and Ti(CO)7

Homoleptic Group 4 metal carbonyl cation and neutral complexes were prepared in the gas phase and/or in solid neon matrix. Infrared spectroscopy studies reveal that both zirconium and hafnium form eight-coordinate carbonyl neutral and cation complexes. In contrast, titanium forms only the six-coordinate Ti(CO)₆⁺ and seven-coordinate Ti(CO)₇. Titanium octacarbonyl Ti(CO)₈ is unstable as a result of steric repulsion between the CO ligands. The 20-electron Zr(CO)₈ and Hf(CO)₈ complexes represent the first experimentally observed homoleptic octacarbonyl neutral complexes of transition metals. The molecules still fulfill the 18-electron rule, because one doubly occupied valence orbital does not mix with any of the metal valence atomic orbitals. Zr(CO)₈ and Hf(CO)₈ are stable against the loss of one CO because the CO ligands encounter less steric repulsion than Zr(CO)₇ and Hf(CO)₇. The heptacarbonyl complexes have shorter metal−CO bonds than that of the octacarbonyl complexes due to stronger electrostatic and covalent bonding, but the significantly smaller repulsive Pauli term makes the octacarbonyl complexes stable.     

BiPO4/石墨烯光电极的制备及其光电催化性能（英文）

光电催化(PEC)氧化法是一种使用半导体电极材料在光和电的共同作用下处理水中有机污染的有效方法.在PEC工艺中,施加偏压不仅可以利用电催化对有机污染物进行降解,而且在偏压作用下,光生电子-空穴对能够得到有效的分离和传输,从而大大提高了机物污染物的去除速率.尽管PEC技术已经取得了许多重要的突破,但是能量转换效率仍然无法满足实际应用.因此,开发具有优异性能,良好稳定性和低成本的光电极材料是一项具有挑战性的研究工作.本文采用两步电沉积法制备了BiPO4纳米棒/还原氧化石墨烯/FTO复合光电极(BiPO4/r GO/FTO).电镜结果表明,电沉积制得的纳米棒状磷酸铋均匀负载在石墨烯纳米片层表面.采用甲基橙为模型体系,考察了复合光电极的光电催化活性.BiPO4/r GO/FTO复合电极的光电催化降解速率是BiPO4/FTO光电极的2.8倍,显示出优良的光电催化活性.实验进一步研究了工作电压和BiPO4沉积时间对甲基橙光电降解性能的影响.最佳的BiPO4沉积时间为45 min,最佳工作电压为1.2 V.捕获实验和ESR实验表明羟基自由基(·OH)和超氧化物自由基(·O2-)是该电极的主要活性物种.BiPO4/r GO/FTO复合电极经过四次循环实验后其降解甲基橙效率保持不变,显示出高稳定性,采用光电流,交流阻抗及其荧光测试对其光催化机理进行推测.结果表明该复合光电极具有高PEC活性的主要原因是:石墨烯的引入加快了BiPO4的电子空穴的分离,拓宽了石墨烯的可见光吸收范围;同时,石墨烯诱导产生的BiPO4混合相也进一步促进了光生电子空穴的分离,提高了光电降解活性.     

含2,6-二甲酰胺基吡啶单元的大环合成、结构及其对四面体构型阴离子的络合性质

采用前体二胺N,N’-(3-胺基苯基)-2,6-二甲酰亚胺吡啶(1)和5,5’-亚甲基双水杨醛(2)进行缩合反应得到含酚羟基的 [1+1] 席夫碱大环L1, 将其中席夫碱C=N双键还原得到环状骨架更具柔性的饱和大环L2. 通过1H NMR、FABMS和元素分析等对大环组成进行了表征, 并通过X射线单晶衍射解析了两个大环的晶体结构. 采用UV-Vis 光谱滴定技术对大环与系列阴离子的络合作用进行了考察, 结果表明席夫碱大环L1对四面体构型的阴离子H2PO4-、 HP2O73-和H2P2O72-有明显的选择性识别作用, 进一步通过UV-Vis 光谱、核磁滴定等技术获得了识别反应的配位比及平衡常数(K), L1对3个磷酸阴离子的络合能力依H2PO4-、HP2O73-和H2P2O72-顺序递增。     

通过赝反伽伐尼反应实现金纳米粒子模块替换

通过可控的方式精确调控纳米粒子的结构仍是一个富有挑战性和鼓舞人心的课题.尽管单原子或两、三个金属原子的精细调控已经在金纳米粒子中实现,涉及三个以上金属原子的取代（模块取代）还没有报道.本工作报道了环己硫醇配体保护的Au₄₈（CHT）₂₆的合成及其通过赝反伽伐尼过程的模块取代.单晶结构揭示模块取代的产物与母体团簇共用一个相似的Au₃₁（CHT）₁₂主体,但剩余部分不同（Au₆（CHT）₁₁ vs.Au₁₆（CHT）₁₄）.一个有趣的发现是模块取代抑制了Au₄₈（CHT）₂₆的光热过程,却增强了它的发射,赋予了所合成团簇更好的双（多）功能应用潜力.光热效应的减弱和发射的增强也暗示了这两种作用能够彼此至少部分转化,对于研究这两种效应之间的相互影响也具有重要的启示.     

Palladium‐Catalyzed Asymmetric [4+3]‐Cyclization Reaction of Fused 1‐Azadienes with Amino‐trimethylenemethanes: Highly Stereoselective Construction of Chiral Fused Azepines

Summary of main observation and conclusion A Pd-catalyzed asymmetric aromative[4+3]-cyclization reaction of amino-trimethylenemethanes(TMM,1d,ip3-oles)with fused 1-azadienes has been developed.This method enables access to the synthetically importance and biologically active benzofuran fused azepines and indeno-azepines in excellent efficiency and stereoselectivity(up to 95%yield,99%ee,>19:1 dr).