Rapid, non-destructive characterization of molecular level chemistry for organic matter (OM) is experimentally challenging. Raman spectroscopy is one of the most widely used techniques for non-destructive chemical characterization, although it currently does not provide detailed identification of molecular components in OM, due to the combination of diffraction-limited spatial resolution and poor applicability of peak-fitting algorithms. Here, we develop a genome-inspired collective molecular structure fingerprinting approach, which utilizes ab initio calculations and data mining techniques to extract molecular level chemistry from the Raman spectra of OM. We illustrate the power of such an approach by identifying representative molecular fingerprints in OM, for which the molecular chemistry is to date inaccessible using non-destructive characterization techniques. Chemical properties such as aromatic cluster size distribution and H/C ratio can now be quantified directly using the identified molecular fingerprints. Our approach will enable non-destructive identification of chemical signatures with their correlation to the preservation of biosignatures in OM, accurate detection and quantification of environmental contamination, as well as objective assessment of OM with respect to their chemical contents.
Characterization of the Ammonium Bending Vibrations in Two-Dimensional Hybrid Lead-Halide Perovskites from Raman Spectroscopy and First-Principles Calculations
二维有机-无机杂化钙钛矿(2D HOIPs)的易合成性和电子性质使得这些自组装体系成为一类重要的能源材料。这些材料的基本构建块包括通常由卤化铅八面体和具有铵官能团的有机分子组成的无机晶格框架。了解无机层和有机层之间的耦合是解开2D HOIP的电子性质与其结构之间关系的关键。在这项工作中,我们利用拉曼光谱测量和第一性原理计算来表征四个2D HOIP中的拉曼活性模式:己基铵碘化铅[(HA)$_2$ PbI $_4$,HA = C $_6$ H $_{13}$ NH $_3^+$ ],己基铵溴化铅[(HA)$_2$ PbBr $_4$ ],丁基铵碘化铅[(BA)$_2$ PbI $_4$,BA = C $_4$ H $_9$ NH $_3^+$ ]和苄基铵碘化铅[(BNA)$_2$ PbI $_4$,BNA = C $_6$ H $_5$ CH $_2$ NH $_3^+$ ]。我们专注于1400-1600 cm $^{-1}$范围内的分子成分的拉曼强度是最强的,并分配在实验中观察到的主要峰作为铵弯曲振动。我们采用密度泛函微扰理论的基础上的局域密度近似和冻结声子的方法的基础上的vdw-DF-cx功能找到定量的实验和计算的拉曼光谱之间的协议。此外,通过比较孤立的分子阳离子与附近的铅卤化物集群的振动光谱,我们显示了无机晶格框架调制的有机阳离子的振动特性。我们的结论是,拉曼活性的铵弯曲模式的性…
Operando Raman probing of mode selective electron phonon coupling in two dimensional halide perovskites
Institut national de la recherche scientifique(国家科学研究学院);Eindhoven University of Technology(埃因霍温理工大学);CNR NANOTEC, c/o Department of Chemistry, University of Bari(巴里大学化学系附属意大利国家研究委员会纳米技术研究所);Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente(特温特大学科学与技术学院及MESA+纳米技术研究所)
Topological insulator Bi2Te3 films synthesized by metal organic chemical vapor deposition
拓扑绝缘体(TI)材料例如Bi 2 Te 3和Bi 2Se 3最近吸引了强烈的兴趣。大规模、高质量的TI薄膜对于开发TI基器件应用是重要的。本文采用金属有机化学气相沉积(MOCVD)方法在GaAs(001)衬底上制备了Bi 2 Te 3薄膜,并通过X射线衍射(XRD)、拉曼光谱、角分辨光电子能谱(ARPES)和电子输运测量等方法对薄膜的结构和电子性质进行了研究。ARPES测量的电子能带结构清晰地揭示了具有单一Dirac锥的特征拓扑表面态(SS),证实了MOCVD Bi 2 Te 3薄膜的TI性质.电阻率和霍尔效应测量表明,体载流子迁移率相对较高,在300 K时约为350 cm^2/Vs,在15 K时约为7,400 cm^2/Vs。我们还测量了薄膜的塞贝克系数。我们的示范高品质的拓扑绝缘体薄膜生长的一个简单的和可扩展的方法是利益的基础研究和实际应用的热电和TI材料。
Unravelling the influence of shell thickness in organic functionalized Cu2O nanoparticles on C2+ products distribution in electrocatalytic CO2 reduction
本研究制备不同 ODA 壳厚的 Cu2O 纳米催化剂,结合表征、DFT 与原位光谱揭示壳层排列及中间体稳定机制,实现乙醇和乙烯总法拉第效率超 73%。
Vibrational and nonlinear optical properties of amine-capped push-pull polyynes by infrared and Raman spectroscopy
用红外光谱和拉曼光谱研究了一系列推拉型多炔化合物的振动性质。强红外和拉曼模式的同时激活,即sp碳链的CC键的集体振动,突出了多炔桥在促进电子给体(D)和受体(A)末端之间的电荷转移方面的有效性,从而表明ad-hoc官能化多炔值得探索作为具有吸引力的一阶光学非线性的有机材料的构建块。这些分子的光学,电子和振动性质进行了研究与密度泛函理论计算的支持下,以及电子和振动的第一超极化率($β$)。对红外光谱的中低区(800-1600 cm $^{-1}$)进行了详细的分析,寻找了不同sp碳链的特定末端的标记带,从而实现了对sp杂化推拉体系的完整振动表征。
Coordination-Induced Tuning of Ligand-Centered Red Emission in a cis-[Cd(Tz)2(py)2] Complex for Light-Emitting Diodes
Universidade Federal do Maranhão(马拉尼昂联邦大学);Iberian Centre for Research in Energy Storage CIIAE(伊比利亚能源存储研究中心);Ceuma University(塞马大学);Federal University of Ouro Preto(欧罗普雷托联邦大学);Universidade Federal do Ceará(塞阿拉联邦大学);Universidade Federal do Triângulo Mineiro(米纳斯吉拉斯三角州联邦大学)
Plasmonic Mediated Atomically Engineered 2D Aluminium Quasicrystals for Dopamine Biosensing
Indian Institute of Technology, Kharagpur(印度理工学院卡拉格普尔分校);State University of Campinas(坎皮纳斯州立大学);Ramakrishna Mission Vidyamandira (Affiliated to University of Calcutta)(罗摩克里希那使命学院(隶属于加尔各答大学));Rice University(莱斯大学);University of Allahabad(阿拉哈巴德大学);Indian Institute of Technology (BHU)(印度理工学院(贝拿勒斯印度教大学));Indian Institute of Technology Kharagpur(印度理工学院卡拉格普尔分校)
Investigating Analyte Co-Localization at Electromagnetic Gap Hot-Spots For Highly Sensitive (Bio)molecular Detection by Plasmon Enhanced Spectroscopies