X-ray nanoscale profiling of layer-by-layer assembled metal/organophosphonate films

The nanoscale structure of multilayer metal/phosphonate thin films prepared via a layer-by-layer assembly process was studied using specular X-ray reflectivity (XRR), X-ray fluorescence (XRF), and long-period X-ray standing wave (XSW) analysis. After the SiO(2) X-ray mirror surfaces were functionalized with a monolayer film terminated with phosphonate groups, the organic multilayer films were assembled by alternating immersions in (a) aqueous solutions containing Zr(4+), Hf(4+), or Y(3+) cations and then (b) organic solvent solutions of PO(3)-R-PO(3), where R was a porphyrin or porphyrin-square spacer molecule. The different heavy metal cations provided X-ray fluorescence marker layers at different heights within the different multilayer assemblies. The XSW measurements used a 22 nm period Si/Mo multilayer mirror. The long-period XSW generated by the zeroth-order (total external reflection) through fourth-order Bragg diffraction conditions made it possible to examine the Fourier transforms of the fluorescent atom distributions over a much larger q(z)() range in reciprocal space than previously achieved.     

X-ray studies of self-assembled organic monolayers grown on hydrogen-terminated Si(111)

The structure of self-assembled monolayers (SAMs) of undecylenic acid methyl ester (SAM-1) and undec-10-enoic acid 2-bromo-ethyl ester (SAM-2) grown on hydrogen-passivated Si(111) were studied by X-ray reflectivity (XRR), X-ray standing waves (XSW), X-ray fluorescence (XRF), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). The two different SAMs were grown by immersion of H-Si(111) substrates into the two different concentrated esters. UV irradiation during immersion was used to create Si dangling bond sites that act as initiators of the surface free-radical addition process that leads to film growth. The XRR structural analysis reveals that the molecules of SAM-1 and SAM-2 respectively have area densities corresponding to 50% and 57% of the density of Si(111) surface dangling bonds and produce films with less than 4 angstroms root-mean-square roughness that have layer thicknesses of 12.2 and 13.2 angstroms. Considering the molecular lengths, these thicknesses correspond to a 38 degrees and 23 degrees tilt angle for the respective molecules. For SAM-2/Si(111) samples, XRF analysis reveals a 0.58 monolayer (ML) Br total coverage. Single-crystal Bragg diffraction XSW analysis reveals (unexpectedly) that 0.48 ML of these Br atoms are at a Si(111) lattice position height that is identical to the T1 site that was previously found by XSW analysis for Br adsorbed onto Si(111) from a methanol solution and from ultrahigh vacuum. From the combined XPS, XRR, XRF, and XSW evidence, it is concluded that Br abstraction by reactive surface dangling bonds competes with olefin addition to the surface.     

Direct observation of cations and polynucleotides explains polyion adsorption to like-charged surfaces

We show an experimental approach for directly observing the condensation of polynucleotides and their electrolyte counterions at a liquid/solid interface. X-ray standing waves (XSW) generated by Bragg diffraction from a d = 20 nm Si/Mo multilayer substrate are used to measure the distinct distribution profiles of the polyanions and simple cations along the surface normal direction with subnanometer resolution. The 1D spatial sensitivity of this approach is enhanced by observing the XSW induced fluorescence modulations over multiple orders of Bragg peaks. We study the interesting divalent cation driven adsorption of anionic polynucleotides to anionic surfaces by exposing a hydroxyl-terminated silica surface to an aqueous solution with ZnCl2 and mercurated poly-uridylic acid (a synthetic RNA molecule). The in situ long-period XSW measurements are used to follow the evolution of both the Zn and Hg distribution profiles during the adsorption process. The conditions and physical mechanisms that govern the observed divalent cation adsorption and subsequent polynucleotide adsorption to an anionic surface are explained by a thermodynamic model that incorporates nonlinear electrostatic effects.     

Structural characterization of 4-bromostyrene self-assembled monolayers on si(111)

Organic functionalization of silicon holds promise for a variety of applications ranging from molecular electronics to biosensing. Because the performance and reliability of organosilicon devices will be intimately tied to the detailed structure of the organic adlayers, it is imperative to develop systematic strategies for forming and characterizing self-assembled monolayers (SAMs) on silicon with submolecular spatial resolution. In this study, we use 4-bromostyrene for the photochemical growth of Br-terminated SAMs on Si(111). A variety of experimental and theoretical techniques including atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), X-ray standing waves (XSW), X-ray fluorescence (XRF), and density functional theory (DFT) have been employed to determine the coverage and conformation of the 4-bromostryene molecules within the SAM. In particular, AFM verifies a continuous and atomically flat SAM, and the XRR data indicate a SAM thickness of 8.50 A and a molecular coverage of 46% of the surface silicon atoms. Because the DFT calculations indicate a molecular length of 8.89 A, the measured XRR thickness implies a molecular tilt angle of approximately 17 degrees. The XRR analysis also suggests that the Br atoms are preserved on top of the SAM in agreement with XPS measurements that show bromine bound solely to carbon and not to silicon. XRF reveals a Br atomic coverage of 50%, again in close agreement to that found by XRR. Single-crystal Bragg diffraction XSW is used to generate a three-dimensional map of the Br distribution within the SAM, which in conjunction with the XRR result suggests that the 4-bromostyrene molecules are tilted such that the Br atoms are located over the T4 sites at a height of 8.50 A above the top bulklike Si(111) layer. The direction of molecular tilt toward the T4 sites is consistent with that predicted by the DFT calculation. Overall, through this unique suite of complementary structural characterization techniques, it is concluded that the Br functional handle is preserved at the top of the SAM and is available for further substitutional chemistry.     

Thickness, surface morphology, and optical properties of porphyrin multilayer thin films assembled on Si(100) using copper(I)-catalyzed azide-alkyne cycloaddition

We report the structure, optical properties and surface morphology of Si(100) supported molecular multilayers resulting from a layer-by-layer (LbL) fabrication method utilizing copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), also known as "click" chemistry. Molecular based multilayer films comprised of 5,10,15,20-tetra(4-ethynylphenyl)porphyrinzinc(II) (1) and either 1,3,5-tris(azidomethyl)benzene (2) or 4,4'-diazido-2,2'-stilbenedisulfonic acid disodium salt (3) as a linker layer, displayed linear growth properties up to 19 bilayers. With a high degree of linearity, specular X-ray reflectivity (XRR) measurements yield an average thickness of 1.87 nm/bilayer for multilayers of 1 and 2 and 2.41 nm/bilayer for multilayers of 1 and 3. Surface roughnesses as determined by XRR data fitting were found to increase with the number of layers and generally were around 12% of the film thickness. Tapping mode AFM measurements confirm the continuous nature of the thin films with roughness values slightly larger than those determined from XRR. Spectroscopic ellipsometry measurements utilizing a Cauchy model mirror the XRR data for multilayer growth but with a slightly higher thickness per bilayer. Modeling of the ellipsometric data over the full visible region using an oscillator model produces an absorption profile closely resembling that of a multilayer grown on silica glass. Comparing intramolecular distances from DFT modeling with experimental film thicknesses, the average molecular growth angles were estimated between 40° and 70° with respect to the substrate surface depending on the bonding configuration.     

LB films of rodlike phthalocyanine aggregates: specular X-ray reflectivity studies of the effect of interface modification on coherence and microstructure

We present here X-ray specular reflectivity (XRR) characterization of the ordering of Langmuir-Blodgett films of the liquid crystalline phthalocyanine (Pc) 2,3,9,10,16,17,23,34-octakis(2-benzyloxyethoxy)copper(II) phthalocyanine, 1, on Si(100) wafers with a native oxide layer and these same substrates modified with monolayers of varying percentages of methyl- and phenyl-terminated silanes. The central copper atom in these Pc's provides for high contrast in X-ray reflectivity for single-bilayer films of 1. The XRR data are modeled as arising from multiple layers of organic material, above and below the rows of copper atoms in the aligned Pc cores; variations in the total thickness of these films, and the spacing between the rows of copper atoms, are attributed to changes in the interaction with the substrate, and changes in the Pc orientation and side chain packing. The most pronounced effect on these parameters comes from variations in the ratio of the phenyl-silane versus methyl-silane content of the substrate modifiers and annealing of these films past their crystalline (K) --> liquid crystalline (LC) mesophase transition temperature. Transfer of multiple bilayers of this Pc leads to additional changes in the thickness of each layer, eventually forming a hexagonal close-packed array, reminiscent of bulk fibers of this material, as revealed by X-ray diffraction (XRD).     

Effects of post-deposition annealing on chemical composition of SiNx film in SiO2/SiNx/SiO2/Si stacked structure

To systematically evaluate the quality of SiN_x films in multi-stacked structures, we investigated the effects of post-deposition annealing (PDA) on the film properties of SiN_x within the SiO₂/SiN_x/SiO₂/Si stacked structure by performing X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), Fourier transform infrared (FT-IR) spectroscopy, and scanning transmission electron microscope–electron energy loss spectroscopy (STEM-EELS) analyses. The XPS results showed that PDA induces the oxidation of the SiN_x layer. In particular, new finding is that Si-rich SiN_x in the SiN_x layer is preferentially oxidized by PDA even in multi-stacked structure. The XRR results showed that the SiN_x layer becomes thinner, whereas the interface layer between the SiN_x layer and Si becomes thicker. It is concluded by STEM-EELS and XPS that this interface layer is SiON layer. The density of N–H and Si–H bonding within the stacked structure strongly depends on the PDA temperature. Our study helps elucidate the properties of SiN_x films in stacked structures from various perspectives.     

Synthesis, characterization, and materials chemistry of Group 4 silylimides

This paper focuses on the development of potential single source precursors for M-N-Si (M = Ti, Zr or Hf) thin films. The titanium, zirconium, and hafnium silylimides (Me(2)N)(2)MNSiR(1)R(2)R(3) [R(1) = R(2) = R(3) = Ph, M = Ti(1), Zr (2), Hf (3); R(1) = R(2) = R(3) = Et, M = Ti (4), Zr (5), Hf (6); R(1) = R(2) = Me, R(3) = (t)Bu, M = Ti (7), Zr (8), Hf (9); R(1) = R(2) = R(3) = NMe(2), M = Ti (10), Zr (11), Hf (12)] have been synthesized by the reaction of M(NMe(2))(4) and R(3)R(2)R(1)SiNH(2). All compounds are notably sensitive to air and moisture. Compounds 1, 2, 4, and 7-10 have been structurally characterized, and all are dimeric, with the general formula [M(NMe(2))(2)(μ-NSiR(3))](2), in which the μ(2)-NSiR(3) groups bridges two four-coordinate metal centers. The hafnium compound 3 possesses the same basic dimeric structure but shows additional incorporation of liberated HNMe(2) bonded to one metal. Compounds 11 and 12 are also both dimeric but also incorporate additional μ(2)-NMe(2) groups, which bridge Si and either Zr or Hf metal centers in the solid state. The Zr and Hf metal centers are both five-coordinated in these species. Aerosol-assisted CVD (AA-CVD) using 4-7 and 9-12 as precursors generates amorphous films containing M, N, Si, C, and O; the films are dominated by MO(2) with smaller contributions from MN, MC and MSiON based on XPS binding energies.     

Solvent extraction of Hf(IV) and Zr(IV) with some 1-phenyl-3-methyl-4-acylpyrazolones-5

The distribution of Hf, Zr and Nb between aqueous solutions of mineral acids and solutions of 1-phenyl-3-methyl-4-acylpyrazolones-5 (acyl=acetyl, ethoxycarbonyl, butyryl, capronyl, capryl and benzoyl) in various organic solvents has been studied. The dependence of the distribution ratio of metal on the acidity of the aqueous phase, the analytical concentrations of reagents and metals, and on the organic solvent was investigated. The composition of the complex extracted is MeP₄ for Hf and Zr. The conditions for the separation of Zr, Hf and Nb are defined, and a comparison is made with extractions by means of thenoyltrifluoroacetone.     

Effect of energy dependence of primary beam divergence on the X-ray standing wave characterization of layered materials.

Incident primary beam divergence is a source of systematic error in X-ray standing wave (XSW) characterization of single and multilayer thin films. Primary beam divergence significantly alters the XSW profile of a layered material and can lead to large errors when used with higher excitation energies. The present study suggests that when one uses Mo-Kalpha excitation, the primary beam divergence should be in range of 0.005(0). On the other hand, in the case of Cu-Kalpha excitation, primary beam divergence can be relaxed up to 0.01(0).     

Effect of water and air-water interface on the structural modification of Ni-arachidate Langmuir-Blodgett films

Nickel arachidate (NiA) Langmuir-Blodgett (LB) films have been deposited on hydrophilic Si(0 0 1) substrates by three (up-down-up) and five (up-down-up-down-up) strokes. During deposition, substrates were kept inside the water subphase for different times after each down stroke. Structural information of all the LB films have been obtained from X-ray reflectivity (XRR) studies. One and two symmetric monolayer (SML) was deposited on top of the asymmetric monolayer (AML) in three and five stokes respectively. All the preformed LB films were then used to go through the air-water interface with the same speed that was used at the time of film deposition. Structural information obtained from the XRR studies show that mainly the top layer density decreases after passing through the air-water interface but the layered structure remains the same. Information obtained from both the XRR and atomic force microscopy (AFM) studies suggest that molecules peeled from the top SML layer do not reincorporate with the LB film through tail-tail hydrophobic interaction. Our study shows that NiA LB film has better stability compared with cadmium arachidate LB film inside the water subphase without forming any out-of-plane molecular reorganization.     

Effect of water contact on the density distributions of thin supported polymer films investigated by an X-ray reflectivity method

The diffusion processes of water molecules into polymer films (PMMA/PS homopolymers and random copolymers) in contact with liquid water were investigated using gravimetric methods and X-ray reflectivity (XRR) analysis. Methods of water contact and XRR measurement were designed for studying the systems in the nonequilibrium state of diffusion. Gravimetric measurements confirmed the Fickian diffusion behavior of films in contact with water. Vertical density distributions in PMMA and methylmethacrylate-rich copolymer films demonstrate the existence of a water-rich layer at the interface. However, with further absorption of water into the film, the overall density increased throughout the film. The results suggest that the diffusion of water into the polymer film occurs to recover density uniformity with a high concentration of water molecules at the surface. Some XRR data for the PS- and styrene-rich copolymer films could not be fit and converted to a vertical density distribution because of their huge diffusion coefficients. However, the reflectivity curves for these films and the vertical density distribution after sufficient water contact suggested that the surfaces of these films were commonly diffused after water contact. Atomic force microscopy (AFM) analysis demonstrated that the surface roughness of these films actually increased with water content.     

Periodic DFT calculations of the stability of Al/Si substitutions and extraframework Zn2+ cations in mordenite and reaction pathway for the dissociation of H2 and CH4

The local stability of Al atoms replacing Si in the zeolite framework is compared for all inequivalent tetrahedral (T) sites in mordenite. For Al/Si substitutions in two T sites the stable location of the compensating extraframework Zn(2+) cation forming a Lewis acid site is determined. In the most stable Zn-MOR structures Zn(2+) is located in a small ring (5MR, 6MR) containing two Al/Si substitutions. In less stable structures the Al atoms are placed at larger distances from each other and Zn(2+) interacts with only one Al site. The simulated adsorption of H(2) and CH(4) shows that adsorption strength decreases with increasing stability of the Zn(2+) Lewis site. A higher adsorption strength is observed for Zn(2+) deposited in the 5MR than for the 6MR. The reactivity of a series of stable Zn(2+) Lewis sites is tested via the dissociative adsorption of H(2) and CH(4). The heterolytic dissociation of the adsorbed molecule on the extraframework Zn(2+) cation produces a proton and an anion. The anion binds to Zn(2+) and proton goes to the zeolite framework, restoring a Br?nsted acid site. Because bonding of the anion to Zn(2+) is almost energetically equivalent for Zn(2+) in any of the extraframework positions the dissociation is governed by stabilizing bonding of the proton to the framework. Those structures which can exothermically accommodate the proton represent reaction pathways. Due to the repulsion between the proton and Zn(2+) the most favorable proton-accepting O sites are not those of the ring where Zn(2+) is deposited, but O sites close to the ring. Large differences are observed for neighboring positions in a- and b-directions and those oriented along the c-vector. Finally, among the stable Zn(2+) Lewis sites not all represent reaction pathways for dehydrogenation. For all of them the dissociation of H(2) is an exothermic process. In structures exhibiting the highest reactivity the Al/Si substitutions are placed at a large distance and the Zn(2+) cation interacts with O-atoms next to Al in the T4 site of the 5MR. This Lewis site is strong enough to break the C-H bond in the CH(4) molecule.     

Morphological behavior of thin polyhedral oligomeric silsesquioxane films at the molecular scale

Synchrotron X-ray reflectivity (XRR) was used to study the structure of thin films of polyhedral oligomeric silsesquioxanes (POSS) with side organic chains of different flexibility and containing terminal epoxy groups. POSS films were deposited from volatile solvents on hydroxylated and hydrogen-passivated silicon surfaces. The XRR data show a variety of structural morphologies, including autophobic molecular monolayers and bilayers as well as uniform films. The role of conformational and energetic factors governing the development of different morphologies in a restricted geometry is discussed.     

Zr(IV) and Hf(IV) based metal-organic frameworks with reo-topology

Zr and Hf based MOFs with enhanced pore accessibility for large molecules and good hydrothermal stability were obtained using a bent dithienothiophene dicarboxylate and Zr(4+) or Hf(4+) source. A modulator (benzoic acid) facilitates formation of an eight-connecting cluster leading to a new framework which adopts reo topology.     

稀土掺杂Ba0.6Sr0.4TiO3薄膜的介电及发光性能

以钛酸锶钡和稀土氧化物粉末靶为靶材, 用离子束溅射法在MgO(100)和Si(100)基片上组合制备了不同掺杂浓度的Ba0.6Sr0.4TiO3:Re(BST:Re)薄膜样品阵列. 沉积得到的多层无定形薄膜经低温扩散、高温晶化, 形成BST:Re多晶薄膜. 以扫描近场微波显微镜测定BST:Re/MgO(Re=Er, Eu, Pr/Al)样品的介电常数, 研究掺杂种类及掺杂浓度对BST薄膜介电常数的影响. 结果表明, 稀土离子的适量掺杂使BST薄膜介电常数有所提高, 其中, Er3+和Eu3+的最佳掺杂浓度分别为4.5%及5.7%(原子分数) 左右时, 介电常数值达到最高. 而共掺杂Pr3+和Al3+的样品则在n(AL):n(Pr)为4-8之间介电性能最佳. 另外, 测量了BST:Re/Si(Re=Er, Eu)样品的光致发光谱, 发现Er3+和Eu3+在BST薄膜样品中的发光猝灭浓度分别为4.20%和8.95%(原子分数).     

The Charge of Solid–Liquid Interfaces Measured by X‐Ray Standing Waves and Streaming Current

Measurements of ion distributions at a charged solid–liquid interface using X‐ray standing waves (XSW) are presented. High energy synchrotron radiation (17.48 keV) is used to produce an XSW pattern inside a thin water film on a silicon wafer. The liquid phase is an aqueous solution containing Br and Rb ions. The surface charge is adjusted by titration. Measurements are performed over a pH range from 2.2–9, using the native Si oxide layer and functional (amine) groups as surface charge. The Debye length, indicating the extension of the diffuse layer, could be measured with values varying between 1–4 nm. For functionalized wafers, the pH dependent change from attraction to repulsion of an ion species could be detected, indicating the isoelectric point. In combination with the measurement of the streaming current, the surface charge of the sample could be quantified.     

Synthesis and catalysis of di- and tetranuclear metal sandwich-type silicotungstates [(gamma-SiW10O36)2M2(mu-OH)2]10- and [(gamma-SiW10O36)2M4(mu4-O)(mu-OH)6]8- (M = Zr or Hf)

The di- and tetranuclear metal sandwich-type silicotungstates of Cs10[(gamma-SiW10O36)2{Zr(H2O)}2(mu-OH)2] x 18 H2O (Zr2, monoclinic, C2/c (No. 15), a = 25.3315(8) A, b = 22.6699(7) A, c = 18.5533(6) A, beta = 123.9000(12) degrees, V = 8843.3(5) A(3), Z = 4), Cs10[(gamma-SiW10O36)2{Hf(H2O)}2(mu-OH)2] x 17 H2O (Hf2, monoclinic, space group C2/c (No. 15), a = 25.3847(16) A, b = 22.6121(14) A, c = 18.8703(11) A, beta = 124.046(3) degrees, V = 8974.9(9) A(3), Z = 4), Cs8[(gamma-SiW10O36)2{Zr(H2O)}4(mu4-O)(mu-OH)6] x 26 H2O (Zr4, tetragonal, P4(1)2(1)2 (No. 92), a = 12.67370(10) A, c = 61.6213(8) A, V = 9897.78(17) A(3), Z = 4), and Cs8[(gamma-SiW10O36)2{Hf(H2O)}4(mu4-O)(mu-OH)6] x 23 H2O (Hf4, tetragonal, P4(1)2(1)2 (No. 92), a = 12.68130(10) A, c = 61.5483(9) A, V = 9897.91(18) A(3), Z = 4) were obtained as single crystals suitable for X-ray crystallographic analyses by the reaction of a dilacunary gamma-Keggin silicotungstate K8[gamma-SiW10O36] with ZrOCl2 x 8 H2O or HfOCl2 x 8 H2O. These dimeric polyoxometalates consisted of two [gamma-SiW10O36](8-) units sandwiching metal-oxygen clusters such as [M2(mu-OH)2](6+) and [M4(mu4-O)(mu-OH)6](8+) (M = Zr or Hf). The dinuclear zirconium and hafnium complexes Zr2 and Hf2 were isostructural. The equatorially placed two metal atoms in Zr2 and Hf2 were linked by two mu-OH ligands and each metal was bound to four oxygen atoms of two [gamma-SiW10O36](8-) units. The tertanuclear zirconium and hafnium complexes Zr4 and Hf4 were isostructural and consisted of the adamantanoid cages with a tetracoordinated oxygen atom in the middle, [M4(mu4-O)(mu-OH)6](8+) (M = Zr or Hf). Each metal atom in Zr4 and Hf4 was linked by three mu-OH ligands and bound to two oxygen atoms of the [gamma-SiW10O36](8-) unit. The tetra-nuclear zirconium and hafnium complexes showed catalytic activity for the intramolecular cyclization of (+)-citronellal to isopulegols without formation of byproducts resulting from etherification and dehydration. A lacunary silicotungstate [gamma-SiW10O34(H2O)2](4-) was inactive, and the isomer ratio of isopulegols in the presence of MOCl2 x 8 H2O (M = Zr or Hf) were much different from that in the presence of tetranuclear complexes, suggesting that the [M4(mu4-O)(mu-OH)6](8+) core incorporated into the POM frameworks acts as an active site for the present cyclization. On the other hand, the reaction hardly proceeded in the presence of dinuclear zirconium and hafnium complexes under the same conditions. The much less activity is possibly explained by the steric repulsion from the POM frameworks in the dinuclear complexes.     

Removal of 2,4-dichlorophenoxyacetic acid by calcined Zn-Al-Zr layered double hydroxide

The adsorption equilibrium, kinetics, and thermodynamics of removal of 2,4-dichlorophenoxy-acetic acid (2,4-D) from aqueous solutions by a calcined Zn-Al layered double hydroxide incorporated with Zr(4+) were studied with respect to time, temperature, pH, and initial 2,4-D concentration. Zr(4+) incorporation into the LDH was used to enhance 2,4-D uptake by creating higher positive charges and surface/layer modification of the adsorbent. The LDH was capable of removing up to 98% of 2,4-D from 5 to 400 ppm aqueous at adsorbent dosages of 500 and 5000 mg L(-1). The adsorption was described by a Langmuir-type isotherm. The percentage 2,4-D removed was directly proportional to the adsorbent dosage and was optimized with 8% Zr(4+) ion content, relative to the total metals (Zr(4+)+Al(3+)+Zn(2+)). Selected mass transfer and kinetic models were applied to the experimental data to examine uptake mechanism. The boundary layer and intra-particle diffusion played important roles in the adsorption mechanisms of 2,4-D, and the kinetics followed a pseudo-second order kinetic model with an enthalpy, ΔH(ads) of -27.7±0.9 kJ mol(-1). Regeneration studies showed a 6% reduction in 2,4-D uptake capacity over six adsorption-desorption cycles when exposed to an analyte concentration of 100 ppm.     

Photoelectrochemical properties of alternating multilayer films composed of titania nanosheets and Zn porphyrin

Alternating multilayer films composed of titania nanosheets and Zn porphyrins were prepared by use of a previously reported Langmuir-Blodgett film-transfer method in order to fabricate photoelectrochemical devices. Closely packed titania nanosheet monolayers on indium tin oxide (ITO), mica, and quartz surfaces strongly adsorbed cationic [5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrinatozinc]4+ (ZnTMPyP4+) by electrostatic interactions. The alternating deposition process afforded nanometer-scale multilayer films with the following structure: solid surface/(titania nanosheet/ZnTMPyP4+)n (n is the number of layers). The multilayer films were characterized by various physical measurements, including AFM, XRD, and UV-visible spectra. The visible-light irradiation of this multilayer film on an ITO electrode in the presence of triethanolamine as an electron donor yielded an anodic photocurrent. The action spectrum was consistent with the absorption spectrum of ZnTMPyP4+, which indicates that the photoexcitation of ZnTMPyP4+ is responsible for the photocurrent generation. However, the photocurrent density decreased with an increasing number of layers, which indicates that the harvesting of photoexcited electrons vertically through the titania nanosheets in the ITO/(titania nanosheet/ZnTMPyP4+)n structure was not efficient. To overcome this problem, the use of a lateral interlayer connection to all of the titania nanosheets with Ag paste was examined. As a result, a dramatic improvement in the photocurrent density was obtained. Thus, for efficient photocurrent generation with the titania nanosheet-ZnTMPyP4+ composite material, the lateral connection to all of the titania nanosheet layers is effective.