Ce(IV) complexes with donor-functionalized alkoxide ligands: improved precursors for chemical vapor deposition of CeO2

Thin films of ceria (CeO(2)) have many applications, and their synthesis by liquid-injection MOCVD (metal-organic chemical vapor deposition) or ALD (atomic layer deposition) requires volatile precursor compounds. Here we report the synthesis of a series of homoleptic and heteroleptic Ce(IV) complexes with donor-functionalized alkoxide ligands mmp (1-methoxy-2-methylpropan-2-olate), dmap (1-(dimethylamino)propan-2-olate), and dmop (2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)propan-2-olate) and their potential as precursors for MOCVD and ALD of CeO(2). New complexes were synthesized by alcohol exchange reactions with [Ce(OBu(t))(4)]. [Ce(mmp)(4)] and [Ce(dmap)(4)] were both found to be excellent precursors for liquid-injection MOCVD of CeO(2), depositing high purity thin films with very low carbon contamination, and both have a large temperature window for diffusion controlled growth (350-600 °C for [Ce(mmp)(4)]; 300-600 °C for [Ce(dmap)(4)]). [Ce(mmp)(4)] is also an excellent precursor for liquid-injection ALD of CeO(2) using H(2)O as oxygen source and demonstrates self-limiting growth from 150 to 350 °C. [Ce(dmap)(4)] has lower thermal stability than [Ce(mmp)(4)] and does not show self-limiting growth in ALD. Heteroleptic complexes show a tendency to undergo ligand redistribution reactions to form mixtures in solution and are unsuitable as precursors for liquid-injection CVD.     

MOCVD-derived highly transparent, conductive zinc- and tin-doped indium oxide thin films: precursor synthesis, metastable phase film growth and characterization, and application as anodes in polymer light-emitting diodes

Four diamine adducts of bis(hexafluoroacetylacetonato)zinc [Zn(hfa)(2).(diamine)] can be synthesized in a single-step reaction. Single crystal X-ray diffraction studies reveal monomeric, six-coordinate structures. The thermal stabilities and vapor phase transport properties of these new complexes are considerably greater than those of conventional solid zinc metal-organic chemical vapor deposition (MOCVD) precursors. One of the complexes in the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentadionato)(N,N'-diethylethylenediamine)zinc, is particularly effective in the growth of thin films of the transparent conducting oxide Zn-In-Sn-O (ZITO) because of its superior volatility and low melting point of 64 degrees C. ZITO thin films with In contents ranging from 40 to 70 cation % (a metastable phase) were grown by low-pressure MOCVD. These films exhibit conductivity as high as 2900 S/cm and optical transparency comparable to or greater than that of commercial Sn-doped indium oxide (ITO) films. ZITO films with the nominal composition of ZnIn(2.0)Sn(1.5)O(z)() were used in fabrication of polymer light-emitting diodes. These devices exhibit light outputs and current efficiencies almost 70% greater than those of ITO-based control devices.     

Synthesis, characterization, and thermal properties of homoleptic rare-earth guanidinates: promising precursors for MOCVD and ALD of rare-earth oxide thin films

Eight novel homoleptic tris-guanidinato complexes M[(N(i)Pr)(2)CNR(2)](3) [M = Y (a), Gd (b), Dy (c) and R = Me (1), Et (2), (i)Pr (3)] have been synthesized and characterized by NMR, CHN-analysis, mass spectrometry and infrared spectroscopy. Single crystal structure analysis revealed that all the compounds are monomers with the rare-earth metal center coordinated to six nitrogen atoms of the three chelating guanidinato ligands in a distorted trigonal prism geometry. With the use of TGA/DTA and isothermal TGA analysis, the thermal characteristics of all the complexes were studied in detail to evaluate their suitability as precursors for thin film deposition by MOCVD and ALD. The (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) showed excellent thermal characteristics in terms of thermal stability and volatility. Additionally, the thermal stability of the (i)Pr-Me(2)N-guanidinates of Y and Dy (1a, c) in solution was investigated by carrying out NMR decomposition experiments and both the compounds were found to be remarkably stable. All these studies indicate that (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) have the prerequisites for MOCVD and ALD applications which were confirmed by the successful deposition of Gd(2)O(3) and Dy(2)O(3) thin films on Si(100) substrates. The MOCVD grown films of Gd(2)O(3) and Dy(2)O(3) were highly oriented in the cubic phase, while the ALD grown films were amorphous.     

以光辅助MOCVD法在有取向Ni衬底及LAO单晶衬底上制备YBCO外延膜的比较研究

采用光辅助金属有机物化学气相沉积(MOCVD)法,在生长有CeO2/YSZ/Y2O3(YSZ为Y稳定的ZrO2)缓冲层的双轴取向Ni衬底上进行了YBa2Cu3O7-x(YBCO)外延膜生长,并与LaAlO3(100)[LAO(100)]单晶衬底上的YBCO外延膜生长进行了对比.发现在Ni衬底上c轴取向YBCO外延膜的生长温度比LAO衬底上的生长温度低约30℃,但生长速度更快.经分析认为,这种差别主要是由于Ni衬底的热导率比LAO衬底高造成的.Ni衬底及LAO衬底上生长的c轴取向YBCO外延膜的超导极限电流密度(Jc)分别约为0.5 MA/cm2及1.8 MA/cm2.     

Encapsulating bis(beta-ketoiminato) polyethers. Volatile, fluorine-free barium precursors for metal-organic chemical vapor deposition

The synthesis, characterization, and incorporation in volatile metal-organic chemical vapor deposition (MOCVD) precursors of a new class of linked beta-ketoiminate-polyether-beta-ketoiminate ligands is presented. These ligands are designed to encapsulate alkaline-earth cations having low charges and large ionic radii. Barium complexes having the general formula Ba[(RCOCHC(R')N)2(R")] (R = tert-butyl or CF3; R' = tert-butyl, methyl, or CF3; R" = -(CH2CH2O)4CH2CH2- or -(CH2CH2O)5CH2CH2)-) were prepared and characterized by 1H and 13C NMR spectroscopy, elemental analysis, and mass spectrometry. Single-crystal X-ray diffraction analysis of 2,2,5,25,28,28-hexamethyl-9,12,15,18,21-pentaoxa-4,25-diene-6,24- diimino-3,27-pentacosadionatobarium(II) reveals a monomeric, nine-coordinate, tricapped trigonal prismatic coordination geometry. Single-crystal X-ray structural analysis of 1,1,1,24,24,24-hexafluoro-4,21-ditrifluoromethyl-8,11,14,17- tetraoxa-3,21-diene-5,20-diimino-2,23-tetracosadionatobarium(II).2DMSO reveals a monomeric, ten-coordinate, distorted tetracapped trigonal prismatic coordination geometry. Volatility data are presented for these barium complexes, demonstrating viability as MOCVD precursors. In addition, it is demonstrated that thin epitaxial films of BaTiO3 can be grown on (001) MgO by low-pressure MOCVD techniques using one of these barium complexes and Ti(dipivaloylmethanate)2(isopropoxide)2 as precursors.     

Transparent conducting oxides: texture and microstructure effects on charge carrier mobility in MOCVD-derived CdO thin films grown with a thermally stable, low-melting precursor

A series of low-melting, thermally stable cadmium metal-organic chemical vapor deposition (MOCVD) precursors have been synthesized, structurally and spectroscopically characterized, and implemented in growth of highly conductive and transparent CdO thin films. One member of the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N-diethyl-N',N'-dimethyl-ethylenediamine)cadmium(II), Cd(hfa)(2)()(N,N-DE-N',N'-DMEDA), represents a particularly significant improvement over previously available Cd precursors, owing to the low melting point and robust thermal stability. High-quality CdO films were grown by MOCVD on glass and single-crystal MgO(100) between 300 and 412 degrees C. Film growth parameters and substrate surface have large effects on microstructure and electron carrier transport properties. Enhanced mobilities observed for highly biaxially textured films grown on MgO(100) vs glass are attributed, on the basis of DC charge transport and microstructure analysis, to a reduction in neutral impurity scattering and/or to a more densely packed grain microstructure. Although single-grained films grown on MgO(100) exhibit greater mobilities than analogues with discrete approximately 100 nm grains and similar texture, this effect is attributed, on the basis of charge transport and Hall effect measurements as well as optical reflectivity analysis, to differences in carrier concentration rather than to reduced grain boundary scattering. Unprecedented conductivities and mobilities as high as 11,000 S/cm and 307 cm(2)/V.s, respectively, are obtained for epitaxial single-grained films (X-ray diffraction parameters: fwhm(omega) = 0.30 degrees, fwhm(phi) = 0.27 degrees ) grown in situ on MgO(100) at a relatively low temperature (400 degrees C).     

Malonate complexes of dysprosium: synthesis, characterization and application for LI-MOCVD of dysprosium containing thin films

A series of malonate complexes of dysprosium were synthesized as potential metalorganic precursors for Dy containing oxide thin films using chemical vapor deposition (CVD) related techniques. The steric bulkiness of the dialkylmalonato ligand employed was systematically varied and its influence on the resulting structural and physico-chemical properties that is relevant for MOCVD was studied. Single crystal X-ray diffraction analysis revealed that the five homoleptic tris-malonato Dy complexes (1-5) are dimers with distorted square-face bicapped trigonal-prismatic geometry and a coordination number of eight. In an attempt to decrease the nuclearity and increase the solubility of the complexes in various solvents, the focus was to react these dimeric complexes with Lewis bases such as 2,2'-biypridyl and pyridine (6-9). This resulted in monomeric tris-malonato mono Lewis base adduct complexes with improved thermal properties. Finally considering the ease of synthesis, the monomeric nature and promising thermal characteristics, the silymalonate adduct complex [Dy(dsml)(3)bipy] (8) was selected as single source precursor for growing DySi(x)O(y) thin films by liquid injection metalorganic chemical vapor deposition (LI-MOCVD) process. The as-deposited films were analyzed for their morphology and composition by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, Rutherford backscattering (RBS) analysis and X-ray photoelectron spectroscopy.     

Novel titanium compounds for metal-organic chemical vapor deposition of titanium dioxide films with an ultrahigh deposition rate

A new titanium diolate compound Ti(mpd)(mdop)(2) (1) containing a beta-ketoester and a dimeric derivative [Ti(mpd)(mdop)(mu-OMe)](2) [2; mpd = 2-methyl-2,4-pentanediolate, mdop = (CH(3))(3)CC(O)C(-)HCOOCH(3)] have been synthesized and characterized by FT-IR, (1)H NMR, (13)C NMR, mass spectroscopy, and elemental analysis. Complex 2 was further characterized by X-ray structural analysis. Both 1 and 2 are fairly stable in air and in solvents such as tetrahydrofuran and toluene. They are also thermally stable and do not leave any residue during flash evaporation at around 280 degrees C. The new titanium complexes were used as precursors for the deposition of TiO(2) thin films by liquid-source metal-organic chemical vapor deposition. Compared with commercial Ti precursors, such as Ti(mpd)(tmhd)(2) (tmhd = 2,2,6,6-tetramethylheptanedionate) and Ti(OPr(i)())(2)(tmhd)(2), the new titanium complexes demonstrated a much higher deposition rate of TiO(2) film growth (3-6 times) at 400-475 degrees C. The deposited TiO(2) film from complex 2 was found to be in a crystalline anatase phase with a smooth surface morphology and low carbon content. Crystal data for 2: 233(2) K, a = 12.570(4) A, b = 13.817(4) A, c = 11.157(3) A, beta = 101.059(5) degrees, monoclinic, space group P2(1)/c, Z = 2.     

Nonfluorinated volatile copper(I) 1,3-diketiminates as precursors for Cu metal deposition via atomic layer deposition

Novel nonfluorinated Cu(diketiminate)L complexes with L = neutral olefinic ligand have been prepared as stable, volatile Cu(I) precursors for the deposition of copper films by an atomic layer deposition (ALD) process. Among them, the complexes of 4-a and 5-a are the most volatile and stable at low temperature (55 degrees C). A clean, conformal copper film was deposited at 120 degrees C in an ALD process. These Cu(I) complexes are the first examples of nonfluorinated copper(I) diketiminates that can be readily applied to an industrial microelectronic fabrication process.     

Deposition of CuInS2 thin films using copper- and indium/sulfide-containing precursors through a two-stage MOCVD method

Copper indium disulfide (CuInS2; CIS) films were deposited on various substrates by two-stage metal-organic chemical vapor deposition (MOCVD) at relatively mild conditions, using Cu- and In/S-containing precursors without toxic H2S gas: first, a pure Cu thin film was prepared on glass or indium/tin oxide glass substrates by using a single-source precursor, bis(ethylbutyrylacetato)copper(II) or bis(ethylisobutyrylacetato)copper(II); second, on the resulting Cu film, tris(N,N-ethylbutyldithiocarbamato)indium(III) was treated to produce CIS films by a MOCVD method at 430 degrees C. In this process, their thicknesses and stoichiometries were found to be elaborately controlled on demand by adjusting the process conditions. The optical band gap of the stoichiometric CIS film was about 1.41 eV, which is in the near-optimal range for harvesting solar radiation energy.     

Tris(phosphino)borato silver(I) complexes as precursors for metallic silver aerosol-assisted chemical vapor deposition

A series of light- and air-stable tris(phosphino)borato silver(I) complexes has been synthesized, structurally and spectroscopically characterized, and implemented in the growth of low resistivity metallic silver thin films by aerosol-assisted chemical vapor deposition (AACVD). Of the four complexes in the series, [RB(CH2PR'2) 3]AgPEt3 (R = Ph (1, 3), (n)Bu (2, 4); R' = Ph (1, 2), (i)Pr (3, 4), complexes 1 and 2 have been characterized by single-crystal X-ray diffraction. Complex 2 represents a significant improvement over previously available nonfluorinated Ag precursors, owing to ease of handling and efficient film deposition characteristics. Thermogravimetric analysis (TGA) shows that the thermolytic properties of these complexes can be significantly modified by altering the ligand structure. Polycrystalline cubic-phase Ag thin films were grown on glass, MgO(100), and 52100 steel substrates. Ag films of thicknesses 3 microm, grown at rates of 14-18 nm/min, exhibit low levels of extraneous element contamination by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that film growth proceeds primarily via an island growth (Volmer-Weber) mechanism.     

Photophysical and structural impact of phosphorylated anions associated to lanthanide complexes in water

A new ligand, LC, bis-[(6'-carboxy-2,2'-bipyridine-6-yl)]phenylphosphine oxide, in which the tridentate 6-carboxy-2,2'-bipyridyl arms are directly linked to a phenylphosphine oxide fragment, has been synthesized. The corresponding [Ln.LC]Cl.xH2O complexes (Ln = Eu, x = 4, and Tb, x = 3) were isolated from solutions containing equimolar amounts of LC and hydrated LnCl3 salts and characterized by elemental analysis, mass spectrometry, and infrared spectroscopy. The interactions of the Eu complex with various anions (AMP(2-), ADP3-, ATP,4- HPO4(2-), and NO3-) were studied by titration experiments, using UV-vis, luminescence spectroscopy, and excited-state lifetime measurements. The results are in keeping with strong interactions with the ADP3-, ATP4-, and phosphate anions in TRIS/HCl buffer (0.01 M, pH = 7.0), as revealed by the determination of the conditional stepwise association constants. These values are higher than the one determined for ligand LB, bis[(6'-carboxy-2,2'-bipyridine-6-methyl-yl)]-n-butylamine (Delta log K approximately 1-2). The interaction of complexes [Ln.LB]+ and [Ln.LC]+ with nitrate, monohydrogenophosphate, methyl phosphate (MeP2-), methyldiphosphate (MeDP3-), and methyltriphosphate (MeTP4-) anions was investigated by means of quantum mechanical (QM) calculations. The results, combined with data on the photophysical impact of the sequential competitive binding of anions to the Eu complexes in water, suggest that LB is too flexible to ensure a good coordination pocket, while the molecular structure of ligand LC stabilizes both the formation of the lanthanide complexes and its adducts with ATP.     

A secondary ion mass spectrometric study of thallium oxide thin films grown via metal organic chemical vapour deposition

Within a comprehensive programme including synthesis via metal organic chemical vapour deposition (MOCVD) and characterization of inorganic compounds and materials of possible interest in technologies based on thin films, results concerning the deposition of metal oxides by means of volatile organometal precursors are reported. In particular, thallium oxide films obtained by the MOCVD technique and commercial powders of Tl₂O₃ and Tl₂O adsorbed on several metal substrates (stainless steel, Si, Cu, Mo, Pt) were studied by secondary ion mass Spectrometry (SIMS) under ion beam bombardment at different ion energies. The positive- and negative-ion mass spectra exhibit typical isotopic patterns of several ionic species produced by interesting interfacial reactions, and the analysis of their relative abundances provides a measure of oxide reactivity towards different substrates. SIMS measurements of metal substrates were also performed. The ability and limits of SIMS in the reactivity study of thallium oxide powders and films and, in addition, in the identification of reaction products evidencing impurity species that, in turn, can be ascribed to the substrates or to the precursors used for the oxide synthesis is pointed out.     

Synthesis and structural characterization of 2,6-dimesitylphenyl complexes of scandium, ytterbium, and yttrium

The molecular structures of a number of 2,6-dimesitylphenyl-based (2,6-dimesitylphenyl = Dmp) complexes of the group 3 elements scandium and yttrium as well as of the lanthanide element ytterbium are reported. Reaction of 1 equiv of DmpLi with 1 equiv of MCl(3) (M = Sc, Yb, Y) in tetrahydrofuran at room temperature followed by crystallization from toluene/hexanes at -30 degrees C produces DmpMCl(2)(THF)(2) (M = Sc: 1; M = Yb: 2) and DmpMCl(2)(THF)(3) (M = Y: 3), respectively. The one-pot reaction of DmpLi with 1 equiv of YbCl(3) in tetrahydrofuran at room temperature followed by addition of 1 equiv of KO(t)Bu produces the heterobimetallic monoalkoxide complex DmpYb(THF)(O(t)Bu)(mu-Cl)(2)Li(THF)(2) (4), which was crystallized from toluene/tetrahydrofuran (20:1) at -30 degrees C. Crystal data for 1: monoclinic, P2(1)/n; T = 203 K; a = 10.178(3) A; b = 15.468(3) A; c = 20.132(5) A; beta = 101.85(3) degrees; V = 3102.0(17) A(3); Z' = 4; D(calcd) = 1.228 g cm(-3); R(1) = 5.89%. Crystal data for 2: monoclinic, P2(1)/n; T = 173 K; a = 10.2447(7) A; b = 15.5683(12) A; c = 20.0979(14) A; beta = 101.749(4) degrees; V = 3238.3(5) A(3); Z' = 4; D(calcd) = 1.485 g cm(-3); R(1) = 4.32%. Crystal data for 3: monoclinic, P2(1)/n; T = 203 K; a = 15.950(3) A; b = 11.865(2) A; c = 18.254(3) A; beta = 92.323(3) degrees; V = 3451.9(10) A(3); Z' = 4; D(calcd) = 1.327 g cm(-)(3); R(1) = 4.43%. Crystal data for 4: triclinic, P1; T = 193 K; a = 10.2252(2) A; b = 11.3497(2) A; c = 18.5814(2) A; alpha = 98.7353(6) degrees; beta = 102.8964(6) degrees; gamma = 94.8058(5) degrees; V = 2062.09(5) A(3); Z' = 2; D(calcd) = 1.375 g cm(-3); R(1) = 4.56%. The molecular structures of 1-3 feature monomeric complexes with distorted trigonal-bipyramidal (1 and 2) or octahedral (3) coordination geometry about the metal atom, with the two chlorine atoms occupying the axial positions. 4 represents the first example of an alkoxide derivative of a terphenyl lanthanide complex. The molecular structure of the ate complex 4 exhibits a heavily distorted trigonal-bipyramidal coordination polyhedron about the ytterbium atom, with one of the mu-chlorine atoms and the oxygen atom of the tetrahydrofuran ligand representing the axial positions of the trigonal-bipyramidal arrangement. A terminal alkoxide ligand is another main feature of the molecular structure of complex 4.     

Synthesis and X-ray crystal structure determination of first examples of donor-functionalized terphenyl lanthanide complexes

The molecular structures of novel donor-functionalized terphenyl derivatives of trivalent ytterbium, yttrium, and samarium of composition [DanipYb(mu2-Cl)2(mu3-Cl)Li(THF)]2 (1) and [DanipLn(mu2-Cl)2(mu2-Cl)Li(THF)2]2 (Ln = Y, 2; Ln = Sm, 3) are reported [Danip = 2,6-di(o-anisol)phenyl]. The complexes are obtained from the reaction of equimolar amounts of DanipLi and LnCl3 (Ln = Yb, Y, Sm) in tetrahydrofuran at room temperature in 60% yield. 1-2 toluene crystallizes in the monoclinic space group Ponebar. Crystal data for 1-2 toluene at 203 K: a = 9.7281(9) A; b = 12.7989(12) A; c = 13.4870(12) A; alpha = 91.553(2) degrees; beta = 103.957(2) degrees; gamma = 109.916(2) degrees; V = 1521.2(2) A(3); Z' = 1; D(calcd) = 1.615 g cm(-3); R1 = 3.43%. 2-toluene crystallizes in the monoclinic space group Ponebar. Crystal data for 2-toluene at 203 K: a = 10.4152(10) A; b = 12.5783(12) A; c = 14.4640(14) A; alpha = 69.963(2) degrees; beta = 80.900(2) degrees; gamma = 66.603(2) degrees; V = 1633.3(3) A(3); Z' = 1; D(calcd) = 1.386 g cm(-3); R1 = 4.07%. 3-toluene crystallizes in the monoclinic space group Ponebar. Crystal data for 3-toluene at 203 K: a = 10.3457(8) A; b = 12.5658(10) A; c = 14.4365(11) A; alpha = 70.2250(10) degrees; beta = 81.2820(10) degrees; gamma = 66.8330(10) degrees; V = 1623.3(2) A(3); Z' = 1; D(calcd) = 1.521 g cm(-3); R1 = 3.40%. Complexes 1-3 represent first examples of donor-functionalized terphenyl complexes of the elements ytterbium, yttrium, and samarium, respectively. The molecular structures of 1-3 feature a "constraint geometry" type arrangement of the Danip ligand at the lanthanide atom. The complexes reported are dimeric and composed of lithium chloride bridged DanipLnCl(2) moieties (Ln = Yb, Y, Sm), stabilized through additional coordination of two methoxy functions to the lanthanide atom.     

The single molecular precursor approach to metal telluride thin films: imino-bis(diisopropylphosphine tellurides) as examples

Interest in metal telluride thin films as components in electronic devices has grown recently. This tutorial review describes the use of single-source precursors for the preparation of metal telluride materials by aerosol-assisted chemical vapour deposition (AACVD) and acquaints the reader with the basic techniques of materials characterization. The challenges in the design and synthesis of suitable precursors are discussed, focusing on metal complexes of the recently-developed imino-bis(diisopropylphosphine telluride) ligand. The generation of thin films and nanoplates of CdTe, Sb(2)Te(3) and In(2)Te(3) from these precursors are used as illustrative examples.     

Synthesis of isostructural cage complexes of copper with cobalt and nickel for deposition of mixed ceramic oxide materials

Heterobimetallic molecular precursors [Co2(acac)2mu-OH)2Cu4(dmae)4Cl4] (2) and [Ni2(acac)2(mu-OH)2Cu4(dmae)4Cl4] (3) [dmaeH = N,N-dimethylaminoethanol and acac = 2,4-pentanedionate] for the deposition of mixed oxide thin films were prepared by the interaction of tetrameric N,N-dimethylaminoethanolato copper(II) chloride, [Cu(dmae)Cl]4 (1) with M(acac)2.xH2O, [M = Co, Ni] in toluene. Both heterobimetallic cage complexes were characterized by melting point, elemental analysis, FT-IR spectroscopy, mass spectrometry, magnetometery, and single-crystal X-ray diffraction. Complexes 2 and 3 are isostructural and crystallize in the monoclinic space group P21/n. A TGA study shows that both complexes undergo controlled thermal decomposition at 450 degrees C to give mixed metal oxides. Solid-state infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and X-ray powder diffraction (XRD) analysis were performed to analyze the chemical composition and surface morphology of the deposited oxide thin films. The results obtained indicate the formation of impurity-free crystalline mixed oxide films with particle sizes ranging from 0.55 to 2.0 microm.     

M?F Interactions and Heterobimetallics: Furthering the Understanding of Heterobimetallic Stabilization

Heterobimetallic complexes containing alkali, alkaline‐earth, and divalent europium metals utilizing the perfluoro‐tert‐butoxide (PFTB) ligand following the general formula, [AM(PFTB)₃(co‐ligand)_x] (A=Na, K; M=Mg, Sr, Ba, Eu; co‐ligand=THF, toluene), have been isolated. These compounds sublime at low temperatures with low residual weight indicating their potential as metal–organic chemical‐vapor deposition (MOCVD) precursors. The complexes have unique molecular architectures that are strongly influenced by M? F interactions, as was verified in the solid state by using X‐ray crystallography. The significance of these interactions were further reinforced by bond‐valence sums analysis and ¹⁹F VT‐NMR spectroscopy, in which rotational energies of 18.75 and 19.08 kcal mol^?1 were measured.     

Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film. TEM image shows that the in-situ formed lanthanide complexes were homogeneously distributed throughout the whole thin film. The quantum yield and the number of water coordinated to lanthanide metal center have been theoretically determined based on the luminescence data.     

Electrochemical deposition of mesoporous nickel hydroxide films from dilute surfactant solutions

A series of micelle-templated mesoporous nickel hydroxide films were prepared by electrochemical deposition from dilute surfactant solutions by using different types of template and by varying plating solvent composition. Lamellar mesostructured Ni(OH)2 films are obtained with only anionic surfactant sodium dodecyl sulfate (SDS) as the template. In particular, a unique cooperative assembly fashion, that is, the combination between Ni2+ and a complex composed of the primary template SDS and a cosurfactant, such as triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) copolymers and poly(ethylene glycol), was explored, by which two-dimensional hexagonal mesoporous Ni(OH)2 films were electrodeposited. Meanwhile, the deposition medium also plays a crucial role in determining the mesostructure of Ni(OH)2 films. For the composite nickel hydroxide films deposited from aqueous solution or dilute aqueous solution of ethylene glycol (<20 wt %) in the presence of SDS or the SDS-poly(alkylene oxide) polymer complexes, a mixed lamellar phase with d(001) = 37.4 A and d(001) = 28.5 A was obtained. However, single lamellar phase with d(001) = 37.4 A was electrodeposited from concentrated aqueous solutions of ethylene glycol (> or = 20 wt %). Furthermore, such deposition baths have access to hexagonal mesoporous nickel hydroxide films with d(100) = 37.4 A at 70 degrees C with the SDS-poly(alkylene oxide) polymer complexes as the templates. Within the potential window for Ni(OH)2, the morphology and quality of mesostructured films are significantly dependent on the deposition potential, while the mesostructures of the composite films always remain unchanged.