Coordination assisted molecular assemblies of perylene-3,4,9,10-tetracarboxylic acid with copper (II) ion at the air/water interface

Perylene-3,4,9,10-tetracarboxylic acid (PTCA) was found to form stable Langmuir films at the air/water interface through the coordination with Cu(II) ion in the subphase although the compound itself could not form monolayer on a plain water surface. The Langmuir films can be transferred onto solid substrates by a Langmuir–Schaefer (LS) method. Surface pressure–area isotherm and measurement of the UV–Vis and FT-IR spectra of the transferred LS films confirmed the coordination between the carboxylic group and Cu(II) ion in the Langmuir films. Atomic force microscopy (AFM) measurements indicated that the Langmuir film was composed of small nanoparticles with a diameter of several tens of nanometers. X-ray diffraction (XRD) measurement on the transferred LS films revealed that the film formed a clear layer structure with a distance of 3.9 nm, which was in agreement with the height measurement from the AFM.     

Long Jumps of an Organic Molecule Induced by Atomic Force Microscopy Manipulation

Non‐contact atomic force microscopy at cryogenic temperatures is used for the controlled lateral manipulation of individual 3,4,9,10‐perylene‐tetracarboxylicacid‐dianhydride (PTCDA) molecules on the Ag(111) surface. The molecules are moved along the [‐110] direction of the Ag lattice in the regime of repulsive tip‐molecule forces performing discrete jumps that span distances from single to multiple lattice spacings. The analysis of the two‐dimensional force field measured before and during the manipulation reveals that the displacement beyond nearest neighbor sites cannot be explained by long range tip‐molecule forces but instead has to involve an energy transfer to translational modes of the molecule. Combined with the results of the simultaneous measurement of the energy dissipation, these findings allow to identify a likely manipulation mechanism and provide insight into the process of energy transfer between excited large molecules and metal surfaces. Furthermore, implications for the theoretical treatment of NC‐AFM based molecule manipulation are discussed.     

Interface formation between two organic films based on phthalocyanine and perylene derivatives

The process of interface formation between two organic films composed of donor (copper phthalocyanine, CuPc) and acceptor (perylene-3,4,9,10-tetracarboxylic dianhydride, PTCDA) molecules has been studied in situ using the total current spectroscopy technique. It is established that the donor-acceptor interaction between CuPc and PTCDA molecules do not distort the energy structure of the density of electron states. The main π*, σ*₁, and σ*₂ bands of antibonding (unoccupied) electron states are identified, which are determined both by C-C bonds in the aromatic rings and by additional C-N and C-O bonds. The width of the interface potential barrier is evaluated and its relation to the limiting polarizability of molecules is demonstrated. The interface potential barrier is formed in the course of negative charge transfer between donor (CuPc) and acceptor (PTCDA) molecules.     

Crystallization of Small Organic Molecules in a Polymer Matrix: Multistep Mechanism Enables Structural Control

The widely employed crystallization of organic molecules in solution is not well understood and is difficult to control. Employing polymers as crystallization media may allow enhanced control via temperature‐induced regulation of polymer dynamics. Crystallization of a small organic molecule (perylene diimide) is investigated in polymer matrices (polystyrene) that enable the mechanistic study and control over order evolution. The crystallization is induced by heating above the glass transition temperature of the polymer, and quenched by cooling, leading to stabilization of crystallization intermediates. The mechanistic studies include direct imaging by electron microscopy, revealing a complex self‐assembly process starting from amorphous aggregates that densify and transform into an unstable crystalline phase of N ,N′‐bis(2,6‐dimethylphenyl)perylene‐3,4,9,10‐tetracarboxylic diimide (DMP‐PDI), followed by a conversion into a more stable crystalline form. Stabilization of crystallization intermediates at room temperature provides diverse structures based on a single molecular component. These findings have implications for the rational design of organic crystalline materials.     

Tuning morphology and fluorescence of aggregated nanostructures of derived perylene diimide molecules

In this paper, we report on the self-assembly of water-soluble N,N'-di(N,N'-dimethyl-dodecane-1, 12-diamide)-perylene-3,4,9,10-tetracarboxylic diimide (PDDoAM) in formic acid and chloride salts for producing varied nano-aggregates with different optical properties. Interestingly, the self-assembly can lead to nanocubic, microsheet and "tower-like" nanostructures respectively, as demonstrated by Scanning Electron Microscopy (SEM) images. The optical properties of molecular aggregates were investigated by means of Confocal Raman Microscopy, indicating the morphologies and fluorescence of these nanomaterials are dependent on acids, acid concentrations and casting methods.     

PTCDA molecules on an InSb(001) surface studied with atomic force microscopy

PTCDA (3,4,9,10-perylene-tetracarboxylic-dianhydride) molecular structures assembled on an InSb(001) c(8 × 2) reconstructed surface have been studied using frequency modulated atomic force microscopy. The high-resolution imaging of the structures is possible through repulsive interactions, using the constant height scanning mode. During initial stages of growth the [110] diffusion channel dominates as indicated by formation of long PTCDA molecular chains parallel to the [110] crystallographic direction on the InSb surface. For a single monolayer coverage a wetting layer of PTCDA is formed. Finally it is shown that the PTCDA/InSb is a promising system for building molecular nanostructures by manipulation of single molecules with the AFM tip.     

From zero to two dimensions: supramolecular nanostructures formed from perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) and Ni on the Au(111) surface through the interplay between hydrogen-bonding and electrostatic metal-organic interactions

Supramolecular self-assembly of the organic semiconductor perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) together with Ni atoms on the inert Au(111) surface has been investigated using high-resolution scanning tunneling microscopy under ultrahigh vacuum conditions. We demonstrate that it is possible by tuning the co-adsorption conditions to synthesize three distinct self-assembled Ni-PTCDI nanostructures from zero-dimensional (0-D) nanodots over one-dimensional (1-D) chains to a two-dimensional (2-D) porous network. The subtle interplay among non-covalent interactions responsible for the formation of the observed structures has been revealed from force-field structural modeling and calculations of partial charges, bond orders and binding energies in the structures. A unifying motif for the 1-D chains and the 2-D network is found to be double N-H??O hydrogen bonds between PTCDI molecules, similar to the situation found in surface structures formed from pure PTCDI. Most interestingly, we find that the role of the Ni atoms in forming the observed structures is not to participate in metal-organic coordination bonding. Rather, the Ni adatoms acquire a negative partial charge through interaction with the substrate and the Ni-PTCDI interaction is entirely electrostatic.      

含咪唑基团苝酰亚胺的合成及其与脱氧核糖核酸相互作用的研究

以3,4,9,10-苝四甲酸二酐为原料,设计合成了含咪唑阳离子基团修饰的苝酰亚胺衍生物(PDI-OH)。通过紫外吸收可见光谱、荧光光谱、黏度实验等技术方法研究合成化合物与小牛胸腺脱氧核糖核酸(ctDNA)的相互作用。结果表明:PDI-OH与ctDNA相互作用后发生明显的减色效应和微弱红移;ctDNA能够使PDI-OH发生荧光猝灭现象,其相互作用荧光猝灭机制为静态猝灭和动态猝灭共存;PDI-OH与ctDNA作用后相对黏度明显减小;ctDNA存在下PDI-OH的Stern-Volmer图为一条曲线,二者以部分嵌插和静电混合作用模式相结合。     

Optoelectronic properties of a perylene substituted (cholesteryl)benzoateethynylene co-polymer

A perylene cholesteryl-benzoateethynylene co-polymer was synthesized by Sonogashira reaction and characterized by NMR, UV–Vis, static and dynamic fluorescence spectroscopy and cyclic voltammetry. The optical and electrochemical properties in solution are consistent with photoinduced energy transfer from the electron donor conjugated backbone to the electron acceptor perylene substituent. Photovoltaic properties are indeed found, even if the performance of the solar cells is quite low due to the formation of aggregates. The incorporation of (6,6)-phenyl C61–butyric acid methyl ester (PCBM), however, increases by an order of magnitude the efficiency of the prototype (from 10⁻⁴ to 10⁻³%) due to both better phase mixing and improved electrical continuity as supported by Atomic Force Microscopy (AFM) and Electrical Force Microscopy (EFM) studies.     

Nanofabrication of PTCDA molecular chains on rutile TiO(2)(011)-(2 × 1) surfaces

The adsorption of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on a rutile TiO(2)(011)-(2 × 1) surface is studied using ultra-high vacuum scanning tunneling microscopy. The self-assembly process is dominated by the fine interplay between the lateral intermolecular interactions and the binding to the substrate. By means of temperature-induced change in the adsorption configuration and the activation of diffusion, the molecules are assembled into one-dimensional chains oriented along the [Formula: see text] crystallographic direction.     

Sensitized monomer fluorescence and excitation energy transfer in perylene-doped phenanthrene in crystalline and in polymer matrix

Sensitized monomer fluorescence and excitation energy transfer in crystalline and spin cast polymer films was investigated at room temperature. The fluorescence spectra of perylene doped phenanthrene reveals the characteristic monomeric emission of perylene and partial quenching of phenanthrene emission. The excimer formation of perylene is not observed in mixed crystalline luminophors and in spin cast films of the phenanthrene luminophors. The observed quenching of phenanthrene emission indicates the excitation energy transfer from phenanthrene to perylene in crystalline as well as in polymer matrix. Energy transfer is not observed in the experiments when phenanthrene and perylene were physically mixed where the components exist separately. The overlap between the excitation spectrum of perylene and emission spectrum of the phenanthrene supports the fact that the perylene molecules accept the excitation energy from phenanthrene. The energy transfer was found to depend upon the perylene concentration.     

Oriented immobilization of IgG on hydroxylated Si(001) surfaces via protein-A by a multiple-step process based on a self-assembly approach

The aim of this study was the oriented immobilization of IgG molecules on the silicon surfaces. A multiple-step procedure was applied for oriented immobilization of IgG in this study. After hydroxylation of the Si(001) surfaces, 3-glycidoxypropyltrimethoxysilane (GPTS) molecules were self-assembled onto these substrates. Dipping time and GPTS concentration were found to be effected by on both layer thicknesses and water-contact angles. 2,2′-(ethylenedioxy)diethylamine (EDA) molecules were then covalently attached to the silicon surface with GPTS molecules. There was no effect of concentration on the formation of EDA molecules on the surfaces, while EDA deposition increased with the dipping time significantly. Imaging ellipsometry and atomic force microscopy (AFM) images exhibited aggregate formation at this step. Protein-A molecules were bound to the free amino groups of EDA molecules on the substrate surface, especially onto the aggregates by using a carbodiimide (i.e., EDAC) as the activating agent. We were able to immobilize IgG molecules in an oriented form onto the protein-A attached surfaces, especially in the regions, where EDA aggregates are located.     

DPPC/胆固醇混合LB膜的AFM研究

用LB膜技术将二棕榈酰磷脂酰胆碱(DPPC)和胆固醇的混合液转移到疏水云母上,并利用原子力显微镜(AFM)在空气中表征了LB膜的性质。结果表明,当C(DPPC)∶C(cho lestero l)=2.6∶1,膜压15mN/m时,能形成有缺陷的LB膜。并分析了这种缺陷LB膜的形成过程。此法制得的LB膜接近受损伤的肾上皮细胞膜,用于诱导晶体生长,从而建立受损伤的肾上皮细胞膜导致肾结石形成的化学模型。     

Improvement of photovoltaic properties by addition of a perylene compound in P3HT:PCBM BHJ system

The synthesized n-type perylene derivative, N,N'-bis-(4-bromophenyl)-1,6,7,12-tetrakis(4-n-butoxy-phenoxy)-3,4,9,10-perylene tetracarboxdiimide (PIBr), was applied as an additive to polymer solar cells (PSCs) with P3HT [poly(3-hexylthiophene)]:PCBM [[6,6]-phenyl C61-butyric acid methyl ester] blend films. Without post thermal annealing, a considerable improvement of about 98% in power conversion efficiency was achieved by the addition of 1 wt% PIBr into a P3HT:PCBM layer, when compared with that of reference cell without the additive. The results, in combination with relevant data from UV-Vis. absorption, photoluminescence, X-ray measurements and carrier mobility studies, revealed that the addition of the perylene compound within active layer contributed to more effective charge transfer and enhanced electron mobility.     

Very high temperature chemical vapor deposition of new carbon thin films using organic semiconductor molecular beam sources

We carried out the preparation and characterization of new carbon films deposited using an organic molecular beam deposition apparatus with very high substrate temperature (from room temperature to 2670 K), which we newly developed. When we irradiated molecular beam of organic semiconductor perylene tetracarboxylic acid dianhydride (PTCDA) on Y_0.07Zr_0.93O₂ (111) at 2170 K, a new carbon material was formed via decomposition and fusing of the molecules. The films were characterized with an atomic force microscope (AFM), Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Zirconium carbide (ZrC) films were identified beneath the topmost carbon layer by XRD and XPS analyses, which results from chemical reactions of the substrate and the molecules. Partially graphitized aromatic rings of PTCDA were observed from Raman spectroscopy. The present technique – very high temperature chemical vapor deposition using organic semiconductor sources – will be useful to study a vast unexplored field of covalent carbon solids.     

Understanding dissipative tip-molecule interactions with submolecular resolution on an organic adsorbate

Three-dimensional force spectroscopy measurements on 3,4,9,10-perylene-tetra-carboxylic dianhydride adsorbed on Ag(111) are combined with first-principles calculations to characterize the dissipative tip-molecule interactions with submolecular resolution. The experiments reveal systematic differences between the energy dissipation at the end groups and the center of the molecules that change with the tip-sample distance. Guided by the strength of the experimental conservative forces, an Ag-contaminated Si tip is identified as the likely tip termination in the experiments. Based on this tip configuration, the energy dissipation in the tip-sample contact is determined from the approach and retraction force curves calculated as a function of distance for different molecule sites. These calculations provide an explanation for the experimental trends in terms of the competition between localized dissipation mechanisms involving the quite mobile oxygen atoms on the sides of the molecule, and global molecular deformations involving the more rigid perylene core. The results confirm that the observed dissipation can be explained in terms of adhesion hysteresis and show the power of combined experimental-theoretical spectroscopy studies in the characterization of the underlying microscopic mechanisms.     

Morphology and electronic structure of thin 3,4,9,10-perylenetetracarboxylic dianhydride layers on Si(001)

The growth of 3,4,9,10-perylenetetracarboxylic dianhydride on Si(001) was examined in the light of varying flux of impinging molecules. Using atomic force microscopy and synchrotron radiation photoelectron spectroscopy Vollmer-Weber growth mode was observed on a wide range of growth rates. The island size initially decreases rapidly with growth rate, for the low growth rate reaches a minimum, and then gradually increases. Polarization dependent photoemission indicates that the orientation of the molecules within the islands remains flat on the substrate.     

Characterization of perylene diimide dye self-assemblies and their use as templates for the synthesis of hybrid and supermicroporous nanotubules

The self-organizing structures formed by a water-soluble perylene diimide dye (PDI) have been studied by several experimental techniques as potential templates for the preparation of hybrid nanomaterials. The dye forms chromonic-nematic and hexagonal liquid crystals in water. The aggregates in liquid crystals consist of one-molecule-wide stacks. From the changes in the solution proton NMR chemical shifts with concentration, it appears that adjacent molecules are twisted. There is significant broadening of the aromatic resonances at higher concentrations, arising from nonmotionally averaged dipole-dipole coupling between adjacent aromatic hydrogens. This is attributed to slow overall rotation of the aggregates in solution, suggesting that they grow up to several tens of nanometers. Dye aggregates serve as templates for the formation of silica tubules (1-5 μm length, average diameter ≈300 nm), with aligned and very thin (1-2 nm) dye nanostripes embedded in the walls. The silica tubes precipitated from solution are formed by the cooperative interaction between PDI and silica species during the sol-gel reaction. Upon calcination, silica nanotubules with supermicroporous walls are obtained. In comparison with conventional surfactant systems, the use of π-π stacked chromonic aggregates brings new possibilities for the templated fabrication of pores with sizes below the mesoporous range. Materials could find applications in photovoltaics as well as in shape selective catalysis and adsorption.     

Color-tunable anisotropic optical films fabricated using perylene diimide mixed with naphthalene benzimidazole

Naphthalene benzimidazole compound (NBI) was synthesized and mixed with perylene diimide (PDI) in order to modulate the absorbance wavelength of an optically anisotropic film between 400 and 550 nm. Equimolar mixture of NBI and PDI could form an ordered lyotropic liquid crystal (LLC) phase in 16.5 N formic acid solution when the solid content was larger than 20 wt.%, even though NBI salt itself did not show any LLC behaviors in all range of concentration. With increasing the content of NBI in NBI/PDI solution, the intensity of absorbance bands between 400 and 450 nm increased but polarization efficiency (P_eff) of the oriented films decreased. Based on the polarized optical microscopy morphological observations, it was realized that the orientation of PDI was hindered by the formation of NBI aggregates. When the molar ratio of NBI and PDI was 0.25, P_eff of the oriented film exhibited 84.1% at 475 nm and 49.8% at 400 nm, which can be compared with those (90.4% at 486 nm and 30.2% at 400 nm) of the oriented film without NBI.     

Assembling of dense fluorescent supramolecular webs via self-propelled star-shaped aggregates

We report a novel mechanism of assembly of dendronized rod molecules into a dense supramolecular fluorescencent web featuring self-propelled mechanistic inward motion of star-shaped aggregates within a solution droplet. We suggest that such a motion (observed in real time) is caused by the self-repulsion of the growing star-shaped nuclei from the liquid-solid-air interface in the course of one-dimensional growth of the anchored arms. An intriguing mechanism discovered here involves microscopic (hundred micrometers) directional motion of the microscopic aggregates driven by one-dimensional molecular assembly, which opens a new venue for guided assembly of dense mesoscopic supramolecular webs. Such assemblies can serve as interesting microfluidic networks, a web of optical switches, and model systems for studying intercellular communication.