A5037565740- Rare-earth and actinide compounds
- Iron-based superconductors research
- Inorganic Chemistry and Materials
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Physics of Superconductivity and Magnetism
- Perovskite Materials and Applications
- Synthesis and characterization of novel inorganic/organometallic compounds
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Quasicrystal Structures and Properties
- Crystallography and molecular interactions
- Corporate Taxation and Avoidance
- Crystal Structures and Properties
- Organic and Molecular Conductors Research
- Inorganic Fluorides and Related Compounds
- MXene and MAX Phase Materials
- Zeolite Catalysis and Synthesis
- Chalcogenide Semiconductor Thin Films
- Silicon Nanostructures and Photoluminescence
- Superconductivity in MgB2 and Alloys
- Coordination Chemistry and Organometallics
- Solid-state spectroscopy and crystallography
- Intellectual Capital and Performance Analysis
- Semiconductor materials and interfaces
University of Houston
2013-2024
Institute of Physics
2016
Chinese Academy of Sciences
2004-2016
Xihua University
2016
Hubei Normal University
2016
Superconductor Technologies (United States)
2015
Max Planck Institute for Chemical Physics of Solids
2009-2011
Max Planck Society
2006-2011
Lawrence Berkeley National Laboratory
2010
Iowa State University
1990-2005
Single crystals of the layered organic-inorganic perovskites, [NH 2 C(I)=NH ] (CH 3 NH ) m Sn I +2 , were prepared by an aqueous solution growth technique. In contrast to recently discovered family, (C 4 H 9 n -1 +1 which consists 〈100〉-terminated perovskite layers, structure determination reveals unusual structural class with sets 〈110〉-oriented CH SnI sheets separated iodoformamidinium cations. Whereas = compound is semiconducting a band gap 0.33 ± 0.05 electron volt, increasing leads more...
New high-T{c} Fe-based superconducting compounds, AFe2As2 with A=K, Cs, K/Sr, and Cs/Sr, were synthesized. The T{c} of KFe2As2 CsFe2As2 is 3.8 2.6 K, respectively, which rises partial substitution Sr for K Cs peaks at 37 50%-60% substitution, the compounds enter a spin-density-wave state increasing electron number (Sr content). represent p-type analogs n-doped rare-earth oxypnictide superconductors. Their electronic structural behavior demonstrate crucial role (Fe2As2) layers in...
The synthesis and properties of LiFeAs, a high-${T}_{c}$ Fe-based superconducting stoichiometric compound, are reported. Single crystal x-ray studies reveal that it crystallizes in the tetragonal PbFCl type (P4/nmm) with $a=3.7914(7)\text{ }\text{\AA{}}$ $c=6.364(2)\text{ }\text{\AA{}}$. Unlike known isoelectronic undoped intrinsic FeAs compounds, LiFeAs does not show any spin-density wave behavior but exhibits superconductivity at ambient pressures without chemical doping. It respectable...
The formation of intermediate phase (CH<sub>3</sub>NH<sub>3</sub>)<sub>2</sub>Pb<sub>3</sub>I<sub>8</sub>·2DSMO in the solution process benefits growth high-quality perovskite CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>film.
Microscopic understanding of interaction between H2O and MAPbI3 (CH3NH3PbI3) is essential to further improve efficiency stability perovskite solar cells. A complete picture from initial physical uptake water molecules final chemical transition its monohydrate MAPbI3·H2O obtained with in situ infrared spectroscopy, mass monitoring, X-ray diffraction. Despite strong affinity MA water, absorbs almost no ambient air. Water penetrate the lattice share space up one per at high-humidity levels....
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Characterization of [NH2C(I):NH2]3MI5 (M = Sn, Pb): Stereochemical Activity in Divalent Tin Lead Halides Containing Single .ltbbrac.110.rtbbrac. Perovskite SheetsShumin Wang, David B. Mitzi, Chris A. Feild, Arnold GuloyCite this: J. Am. Chem. Soc. 1995, 117, 19, 5297–5302Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1...
We report the implementation of field effect transistors based on exfoliated nano-membranes a layered two-dimensional semiconductor SnS(2), which exhibit an on/off ratio exceeding 2 × 10(6) and carrier mobility ∼1 cm(2) V(-1) s(-1). The results demonstrate great potential with finite band gap, as building block for future nanoelectronic applications complementary to graphene-based materials zero or small gaps.
The successful incorporation of an organic chromophore with highly polarizable lead iodide chains in organic–inorganic hybrid is revealed this communication. synthesis, structure, and preliminary studies the linear nonlinear optical (NLO) properties compound are divulged. synergism exhibited between inorganic polymers hyperpolarizable molecules provides a route to new multi-functional NLO materials.
Eine eckenverknüpfte Kette „nackter”︁ nido-Ge92−-Cluster (siehe Bild) ist das Charakteristikum eines neuartigen polymeren Zintl-Anions, aus der binären Legierung „KGe4”︁, Ethylendiamin und [18]Krone-6 gebildet wird. Die überraschende Bildung des Anions durch Polymerisation von nido-Ge94−-Clustern widerspricht dem bekannten Zwei-Elektronen-Oxidationsverhalten nido-Clustern steht im Kontrast zur Existenz isolierten closo-Ge92−-Anions. Der neuartige, halbleitende Cluster-„Draht”︁ zeigt direkt...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Methylviologen Lead(II) Iodide: Novel [PbI3-]∞ Chains with Mixed Octahedral and Trigonal Prismatic CoordinationZhongjia Tang Arnold M. GuloyView Author Information Department of Chemistry Texas Center for Superconductivity University Houston, 77204-5641 Cite this: J. Am. Chem. Soc. 1999, 121, 2, 452–453Publication Date (Web):December 29, 1998Publication History Received30 July 1998Published online29 December inissue 1 January...
A new layered Ti-based pnictide oxide superconductor, Ba(1-x)Na(x)Ti(2)Sb(2)O (0.0 ≤ x 0.33), is reported. X-ray studies revealed that it crystallizes in the tetragonal CeCr(2)Si(2)C structure. The undoped parent compound, BaTi(2)Sb(2)O [P4/mmm; a = 4.1196(1) Å; c 8.0951(2) Å], exhibits charge density wave (CDW)/spin (SDW) transition at 54 K. Upon chemical doping with Na, CDW/SDW systematically suppressed, and superconductivity arises critical temperature (T(c)) increasing to 5.5 Bulk was...
A thorough characterization of field effect transistors with conduction channels made SnS2−xSex nanocrystals having different selenium content is presented. The main increasing the a suppression drain-source current modulation by gate voltage. temperature dependence conductivity for all compositions characterized an activation energy that gradually decreases x. simple donor model, parameters SnS2 and SnSe2 deduced from density functional theory, suggests change in mostly due to enhanced...
The observation of low-energy edge photoluminescence and its beneficial effect on the solar cell efficiency Ruddlesden–Popper perovskites has unleashed an intensive research effort to reveal origin. This effort, however, been met with more challenges as underlying material structure still not identified; new modelings observations also do seem converge. Using two-dimensional (2D) (BA)2(MA)2Pb3Br10 example, we show that three-dimensional (3D) MAPbBr3 is formed due loss BA edge. self-formed...
The synthesis of clathrate-II germanium □24Ge136 in an ionic liquid was recently discovered.1 key step this process, the controlled oxidation reactive precursor phases by a protic acid, successfully applied to silicides M4Si4 (M = Na, K). Through method, clathrate-I compounds composition M8-xSi46 were obtained as crystalline products. synthetic method demonstrates mild oxidative route large class metastable intermetallic compounds.
Polarized Raman spectra of nonsuperconducting ${\text{SrFe}}_{2}{\text{As}}_{2}$ and superconducting ${\text{K}}_{0.4}{\text{Sr}}_{0.6}{\text{Fe}}_{2}{\text{As}}_{2}$ $({T}_{c}=37\text{ }\text{K})$ microcrystals are reported. All four-phonon modes $({A}_{1g}+{B}_{1g}+2{E}_{g})$ allowed by symmetry found identified. Shell model gives reasonable description the spectra. No detectable anomalies observed near tetragonal-to-orthorhombic transition in or...
A chemical analysis and detailed structural characterization, using X-ray single crystal neutron powder diffraction, of the binary lithium-tin compound "Li(4.4)Sn" is presented. Phase analyses subsequent refinements result in reformulation as Li(17)Sn(4). The lithium-rich phase crystallizes with a complex cubic structure space group Ffourmacr;3m, = 19.6907(11) A, Z 20. improved determination indicates well-defined lithium atom positions, some which differ from those previously reported....
The many A5B3 phases that exhibit hexagonal Mn5Si3-type structures by and large have a nearly unique abilities to bind diverse heteratoms Z in preformed cavity within chain of confacial trigonal antiprisms A. historical development this chemistry as interstitially stabilized Nowotny recent research clarify the necessity for range possible certain hosts are described. Some may 20 different interstitial Z. Structures, stoichiometric relationships, volume effects, electronic guidelines,...
We present a detailed study of $^{75}\text{A}\text{s}$ nuclear magnetic resonance Knight shift and spin-lattice relaxation rate in the normal state stoichiometric polycrystalline LiFeAs. Our analysis Korringa relation suggests that LiFeAs exhibits strong antiferromagnetic fluctuations, if transferred hyperfine coupling is dominant interaction between nuclei Fe electronic spins, whereas for an on-site scenario, these are weaker, but still to account our experimental observations....
The structures of two trigonal-rhombohedral CaSi2 polymorphs (space group R3̅m) were studied by X-ray diffraction and polarized Raman scattering spectroscopy. Raman-active even-parity vibrational modes A1g Eg are unambiguously identified assigned to the specific lattice eigenmodes. Experimental data found be in very good agreement with those predicted density functional theory dynamics calculations. transformation 6R structural modification into its 3R polymorph, high-temperature annealing...
Chemistry with a golden touch: The first examples of organic-based mixed-valent AuI/AuIII layered perovskites are reported (see picture). crystal structures the new hybrid compounds feature [AuI2]−/[AuI4]− layers pillared by I3− ions and appropriate organic dications. measured optical band gaps organic–inorganic semiconductors smaller than value for Cs2Au2I6.