Tetracarboxylic Diimide Research Articles

New organic–inorganic hybrid materials based on perylene diimide–polyhedral oligomeric silsesquioxane dyes with reduced quenching of the emission in the solid state

Abstract Solid state luminescent materials are the subject of ever growing interest both from a scientific and a technological point of view because high-tech applications of light emitting materials very often require their use in the condensed phase. Aggregation caused quenching processes however represent an obstacle to the development of most luminogens in the condensed phase. This is why particularly fascinating are those materials showing high emission intensity in the solid state. Aggregation caused quenching is particularly detrimental for π-extended polycyclic aromatic hydrocarbons, for example perylene tetracarboxylic acid diimides which are characterized by a near-unity fluorescence quantum yield in solution but are far less emissive in the solid state. Here we report on the easy preparation and on the optical investigation of perylene tetracarboxylic acid diimide derivatives linked to the inorganic cage of polyhedral oligomeric silsesquioxanes. These new hybrid perylene diimide–polyhedral oligomeric silsesquioxane dyes show in solution the typical absorption and emission features of the perylene diimide fragment, with a quantum efficiency close to unity. Moreover, in the solid state (both as spin-coated films and powders) the electronic absorption spectra indicate a reduced fluorophore aggregation and significant quantum yield efficiencies induced by the positive effect of the polyhedral oligomeric silsesquioxane cage.

In Situ Monitoring Alzheimer's Disease β‐Amyloid Aggregation and Screening of Aβ Inhibitors Using a Perylene Probe

A cationic perylene tetracarboxylic acid diimide derivative (1) is employed as a probe for in situ monitoring of Aβ aggregation and screening Aβ inhibitors. The assay is based on the fluorescence change through the aggregation of compound 1 following Aβ assembly. Importantly, this probe, compared with the well known amyloid-staining compound thioflavin T (ThT), is more sensitive to Aβ oligomer, which is highly toxic and plays a crucial role in the early stages of Alzheimer's disease.

Electrochromic Poly(DNTD)/WO3 Nanocomposite Films via Electorpolymerization

Poly(DNTD,N,N′-di[p-phenylamino(phenyl)]-1,4,5,8-naphthalene tetracarboxylic diimide) and its nanocomposite film incorporated with WO3 nanoparticles was prepared by a facile electropolymerization method on an indium in oxide (ITO) coated glass slide from the DNTD monomer and WO3 nanoparticles suspended methylene chloride solution. The morphology and microstructure of the nanocomposite film were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM image shows that the WO3 nanoparticles are uniformly embedded in the polymeric matrix. The nanocomposite film also displays smooth topography with evenly sized and uniformly distributed nanoparticles under high resolution AFM observations. An air-stable electrochromical window was assembled and obtained by a homemade electrochemical cell to study the electrochromism and stability of the nanocomposite film. The composite film exhibits multiple colors at both the cathodic and anodic potentials, i.e., light blue at −1.4 V, o...

Device characteristics of perylene-based transistors and inverters prepared with hydroxyl-free polymer-modified gate dielectrics and thermal post-treatment

Organic field-effect transistors (OFETs) and complementary inverters were produced on the basis of n-type N,N′-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8) using the neutral cluster beam deposition (NCBD) method. Significant improvements in surface morphology and crystallinity were observed after the surface modification of SiO2 gate dielectric layers with hydroxyl-free polymer insulators such as polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), and thermal post-treatment. Electric characteristics and operational stability of PTCDI-C8-based OFETs were also clearly enhanced after the surface modification, and in particular, the thermally post-treated OFETs with COC-modified SiO2 gate dielectrics exhibited a high room-temperature mobility of 0.68cm2/Vs. Two structural types (generic vs. encapsulated) of inverters in top-contact configuration were fabricated by integration of the p-type pentacene and n-type PTCDI-C8 OFETs using COC-modified SiO2 gate dielectrics. Due to the increased electron mobilities and good coupling between p- and n-type OFETs, hysteresis-free, fast-switching inverters were realized with high gains of ∼20 in the first and third quadrants of voltage transfer characteristics under ambient conditions. The device characteristics of the encapsulated inverters monitored as a function of the time were well maintained with slight degradation.

Perylene ligand wrapping G-quadruplex DNA for label-free fluorescence potassium recognition

A perylene ligand, N,N-bis-(1-aminopropyl-3-propylimidazol salt)-3,4,9,10-perylene tetracarboxylic acid diimide ligand (PDI), which consisted of π-conjugated perylene moiety and hydrophilic side chains with positively charged imidazole rings, was used to wrap G-quadruplex for fluorescence turn-on K+ recognition. Electrostatic attraction between PDI's positively charged imidazole rings and DNA's negatively charged phosphate backbones enabled PDI to accumulate on DNA. Upon trapping K+, these G-rich DNA sequences transitioned to G-quadruplex. Subsequently, PDI ligands wrapped G-quadruplex, in which the flat aromatic core of PDI ligand interacted with G-quartet through π–π stacking and the side chains were positioned in grooves through electrostatic interactions. Consequently, the interaction mode change and conformational transition from PDI stacked G-sequence to PDI wrapped G-quadruplex led to PDI fluorescence enhancement, which was readily monitored as the detection signal. This strategy excluded the sequence tagging step and exhibited high selectivity and sensitivity towards K+ ion with the linear detection range of 10–150nM. Besides, PDI ligands may hold diagnostic and therapeutic application potentials to human telomere and cancer cells.

Preclusion of nano scale self-assembly in block-selective non-aqueous solvents for rod–coil and coil–rod–coil macromolecular surfactants based on perylene tetracarboxylic diimide

Self-assembly of amphiphilic molecules ranging from simple surfactants to block copolymers in a solvent depends on one part of the molecule (one block in block copolymers) being soluble, and the other not. The aggregation of the insoluble segment in the block-selective solvent leads to the self assembly. In this paper, we describe a system of amphiphilic rod–coil and coil–rod–coil molecules, which do not show self assembly in block-selective non-aqueous solvents. We prepared rod–coil molecules based on hydrophilic propylene oxide/ethylene oxide copolymer (PO–EO copolymer) (Jeffamine®) as the flexible segment and photo-conducting large aromatic perylenediimide (PTCDI) as the rod. PO–EO copolymer was attached either to one side of PTCDI (MJ–PTCDI) or both sides (DJ–PTCDI). The former can be considered an inverse macromolecular surfactant, since the tail is hydrophilic and the head is hydrophobic. The DJ–PTCDI is a pseudo Gemini surfactant. Because of the presence of the chromophore, UV–Vis and fluorescent spectra could be used to study the self assembly of these amphiphilic rod coil polymers in solution. PTCDI forms π-interaction mediated aggregates in aqueous solution and these are H-stacked in MJ–PTCDI and J-stacked in DJ–PTCDI. Variable temperature UV and NMR spectra show that the assembly is stable over a large temperature range in water. The aggregates are also stable up to a pH of 12. However, when a non-aqueous solvent is used, no aggregation occurs. This is attributed to the “solvation” of the π-system of the PTCDI. With the addition of water, such solvation seems to be interrupted and aggregation occurs when water becomes a major component. We find that the mole percentage of the aggregates in acetone/water mixtures increases almost linearly with the concentration of water, providing a route to control the extent of aggregation of the chromophores. Due to the long, waxy PO–EO copolymer, MJ–PTCDI and DJ–PTCDI do not show liquid crystalline behavior or nanorod morphology, which were seen with short side chains. The optical microscopy of the bulk material shows aggregated crystals of PTCDI in the waxy matrix, showing that even in the presence of PO–EO copolymer, the molecular assembly of PTCDI takes place in the bulk. Secondary assembly was seen, in that upon ageing of the aqueous solutions, the drop cast films show that the spherical aggregates one-dimensionally coalesced into long fibers. Although UV–Vis spectra indicated no aggregation in non-aqueous solvents, drop-cast films of these solutions show needle-like aggregates and Lego-like assemblies.

ChemInform Abstract: Angular‐Shaped Naphthalene Tetracarboxylic Diimides for n‐Channel Organic Transistor Semiconductors.

A series of compounds based on the angular-shaped naphthalene tetracarboxylic diimide core have been synthesized, characterized and used as active layers of organic field-effect transistors (OFETs). The fabricated OFET devices exhibit n-type semiconducting characteristics, demonstrating the first examples of semiconductors based on angular-shaped naphthalene tetracarboxylic diimides.

Single Mesowire Transistor From Perylene Tetracarboxylic Diimide

We have recently fabricated new nano/mesowires of perylene tetracarboxylic diimide (PTCDI) without side chains by self-assembling them from a gas phase. In this letter, we discuss a single PTCDI mesowire transistor that was successfully fabricated, characterized, and modeled. This organic n-channel field effect transistor shows good output and transfer characteristics. Our transistor model includes the Poole-Frenkel electric field dependence of charge carrier mobility in organic materials and fits all experimental output characteristics of the transistor. The zero-field charge carrier mobility of the PTCDI mesowire is found to be 0.72 cm2/(V·s). The experimental results are promising for the further development of single nanowire transistors and advancement of organic nanoelectronics.

Modulating Morphology of Thiol-Based Monolayers in Honeycomb Hydrogen-Bonded Nanoporous Templates on the Au(111) Surface: Simulations with the Modified Force Field

The difference in monolayer morphology caused by different functional thiols (ASH, BP3SH, and C12SH) within the surface-supported porous network of naphthalene tetracarboxylic di-imide (NDI) and melamine (MEL) molecules has been investigated by molecular dynamics simulations with the modified force field. The hydrogen-bonded bimolecular network is taken as the template when different thiols are deposited on the Au(111) surface. Force field parameters of intermolecular (NDI–NDI, MEL–MEL, NDI–MEL, and thiol–thiol) and interfacial (Au···S) interactions are modified to reproduce MP2 potential energy curves and the adsorption height. Interfacial interactions between the network and the Au(111) surface support the NDI–MEL bimolecular template, lying flat in an ordered hexagonal pattern on the substrate. The packing morphology of the triple hydrogen-bonded network obtained from molecular dynamics simulations and quantum chemical calculations matches the image from the scanning tunneling microscope. The backbone ...

Stability of small chemical groups on hexagonal-SiC(0001) surfaces: A theoretical study

Density functional theory (DFT) calculations are used to investigate the stability on SiC(0001) surfaces of different chemical groups -NH2, -NO2, -CH3, -OH, -SH and -CN. The adsorption stability decreases in the order -NO2>−OH>−NH2>−SH>−CN>−CH3. The stability of the single molecule-substrate bond is strongly influenced by the polarizability, which in turn depends on different parameters such as the electronegativity, atomic size and chemical environment. In a further step, methyl (−ACH3) and phenyl (−AC6H5) substituted groups are also considered and similar behaviour is observed. The inductive effect of the -CH3 or -C6H5 groups modifies the polarization of the Si adatom-molecule bond and the steric hindrance due to their size influences the molecular orientation. These two parameters affect the calculated adsorption energy, and are more important for –C6H5 substituent. This study provides clear tendencies that can be applied to more complex systems. Comparison of the adsorption of two large molecules, H2Pc (metal-free phthalocyanine) and PTCDI (perylene tetracarboxylic diimide) on the SiC(0001) surface is presented as an example.

Orientation of Nonplanar Molecules in Polycrystalline Layers from Infrared Spectra: Core-Chlorinated Naphthalene Tetracarboxylic Diimides

By means of infrared spectroscopic ellipsometry in the range of 350–5000 cm–1, the anisotropic dielectric functions of dichlorinated naphthalene diimide with fluoroalkyl chains (NDI-F), a novel high-performance n-type organic semiconductor, thin films were determined with high precision. Films of varying thicknesses (between 5 and 60 nm) evaporated in vacuum or spin coated from solution on different silicon wafers can all be described by the same anisotropic vibrational susceptibility, indicating weak dependence of the molecular orientation on processing procedure and film thickness for this material. It is shown how to determine the predominant molecular orientation by thorough comparison of ellipsometric measurements with calculations based on density functional theory. The method used additionally reveals subtle discrepancies between experiment and single molecule calculation which certainly arise from intermolecular interaction.

Self-assembly and optical properties of N N′-bis(4-(1-benzylpiperidine))perylene-3,4,9,10-tetracarboxylic diimide

Well-defined nanobelts with strong fluorescence were fabricated from a perylene tetracarboxylic diimide molecule modified with specific side-chain substitution. The new perylene diimide was characterised by 1H, 13C NMR, mass and IR spectral techniques. The photophysical and electrochemical properties were investigated by UV–vis absorption, fluorescence, differential scanning calorimetry and cyclic voltammetry. 1D nanobelt self-assembly of the compound was studied with optical, fluorescence and scanning electron microscopic techniques. The observed self-assembly was supported by computational studies using density functional theory and natural bond order analysis. The optimised molecule was fit into crystal space theoretically, and the observed band gap was correlated well with optical and electrical properties.

Synthesis and characterization of pyromellitic diimides-containing conjugated polymers

Conjugated polymers based on pyromellitic diimides, the most compact aromatic tetracarboxylic diimides have been synthesized. Relatively low-lying LUMO energy levels and strong intermolecular interactions, together with solution processibility might enable them to become a promising new class of polymers for n-channel semiconducting materials.

Organic phototransistors based on solution grown, ordered single crystalline arrays of a π-conjugated molecule

High quality, single crystalline, ordered arrays of a π-conjugated organic molecule, N,N′-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8), were grown by solution processing and used to fabricate a low-cost, high-performance organic phototransistor (OPT). The single crystalline nature of the microstructure was investigated using 2D-GIXD measurement. The organic field-effect transistor fabricated using periodic arrays of elongated crystals exhibited a photoresponsivity (P) of ca. 1 A W−1 and a photo to dark current ratio (Ion/Ioff) of 2.5 × 103 at VG = 12 V and a maximum P of ca. 7 A W−1 at the high gate bias regime (VG = 50 V) with an optical power of ca. 7.5 mW cm−2. With polymeric gate dielectric, the OPT exhibited very stable n-type characteristics both in the dark and under light illumination and showed reproducible photo-switching behavior. The dependence of the photocurrent on the gate/drain voltage and on illumination intensity provided an effective way to control the number of photo-carriers generated in the active material, enabling the precise tuning of the device's performance. Performance comparison between OPTs with ordered crystal arrays and thin films of PTCDI-C8 confirmed that the material's intrinsic properties were better realized in the crystalline device, presumably because of higher charge carrier mobility and better charge transport capability. This one-step, solution-based, self-assembly fabrication of multifunctional (photodetection, photoswitching, signal amplification) optoelectronic devices has potential to aid the development of organic semiconductors with high-quality micro/nanostructures for large-scale application and low-cost optoelectronic devices.

Synthesis of novel triarylamine-based dendrimers with N4,N6-dibutyl-1,3,5-triazine-4,6-diamine probe for electron/energy transfers in H-bonded donor–acceptor–donor triads and as efficient Cu2+ sensors

Two novel highly soluble triarylamine dendrimers TPAD1 and TPAD2 with N4,N6-dibutyl-1,3,5-triazine-4,6-diamine probe were synthesized via normal synthetic routes. Both dendrimers (TPAD1 and TPAD2) form H-bonded donor–acceptor–donor (D–A–D) supramolecular triads TPAD1-PBI-TPAD1 and TPAD2-PBI-TPAD2 with 3,4,9,10-perylene tetra carboxylic diimide derivative (PBI). The presence of multiple H-bonds in the solution state was elucidated by 1H NMR titrations and IR spectral studies. J-aggregations and electron/energy transfers provided by both dendrimers were verified by UV–Vis and photoluminescence (PL) titrations with PBI and the particle sizes of supramolecular triads were calculated by X-ray diffraction (XRD) analysis. Similarly, both dendrimers also showed sensitivities towards Cu2+ in comparison with 19 interfering metal ions, which were evidenced via UV–Vis and PL titraions in both single and dual metal systems. The maximum detection limit of Cu2+ ions was determined to be 20 ppm from PL titrations for both dendrimers, and the 1 : 2 stoichiometry of the complexes formed by both dendrimers (TPAD1-Cu2+ and TPAD2-Cu2+) were calculated by Job plots based on UV–Vis absorption titrations. More importantly, the binding mechanism of the 1,3,5-triazine-4,6-diamine probe of both dendrimers was well characterized by 1H and 13C NMR titrations ([D8]THF : D2O = 2 : 1 in vol.) and supported by the fluorescence reversibility by adding metal ions and PMDTA sequentially.

Core-extended rylene dyes via thiophene annulation

Annulation of thiophenes directly into the bay regions of rylene dyes through effective Stille coupling and subsequent ring-fusion under Scholl conditions leads to core-extended rylene tetracarboxylic diimides with interesting electro-optical properties.

Angular-shaped naphthalene tetracarboxylic diimides for n-channel organic transistor semiconductors

A series of compounds based on the angular-shaped naphthalene tetracarboxylic diimide core have been synthesized, characterized and used as active layers of organic field-effect transistors (OFETs). The fabricated OFET devices exhibit n-type semiconducting characteristics, demonstrating the first examples of semiconductors based on angular-shaped naphthalene tetracarboxylic diimides.

Interface properties of OFETs based on an air‐stable n‐channel perylene tetracarboxylic diimide semiconductor

AbstractIn this study, several experimental techniques were employed to gain insights into the molecular interactions at the interfaces in organic field‐effect transistors (OFETs). A self‐assembled monolayer (SAM) was applied to the gate insulator to influence the interactions at the interface. Macroscopic electrical measurements, microscopic potentiometry, absorption/luminescence spectroscopy, and ellipsometry are combined to study top‐contact OFETs based on an air‐stable n‐channel perylene derivative. They show clearly the advantage and capability of local electrical investigations compared to DC electrical characterization. The DC electrical measurements provide an improvement of the electron mobilities within the channel and unchanged contact resistances (within the error bars). Only the potentiometry allowed a deeper insight: It reveals a small decrease of the source contact resistance and a drain bias dependence of the mobility, which decreases due to prior hydrophobization of the SiO2 gate insulator. This is attributed to different charge carrier trap concentrations and injection barriers in the organic semiconductor near the dielectric interface caused by diffused water which is discussed in detail. The optical absorption/luminescence spectroscopy and ellipsometry indicate an unchanged ordered molecular arrangement with a molecular tilt angle of (33 ± 4)° with respect to the dielectric surface and rather weak intermolecular interaction for the devices with treated and untreated SiO2.

Decorated graphene sheets for label-free DNA impedance biosensing

An efficient DNA impedance biosensing platform is constructed, in which positively charged N,N-bis-(1-aminopropyl-3-propylimidazol salt)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) is anchored to graphene sheets. The π–π stacking and electronic interactions are elucidated by the distinct absorption features in UV–vis spectra and by quenching perylene fluorescence in contact with graphene. The rational design and tailoring of graphene surface invest it with desired properties (dispersive, structural, photoelectrical and conductive, etc.) and boost its application. Electrostatic interaction between PDI’s positively charged imidazole rings and negatively charged phosphate backbones of single-stranded DNA (ssDNA) facilitates ssDNA immobilization. This manner is different from these mainly based on the attraction between the rings in DNA bases and the hexagonal cells of graphene, which is disturbed after hybridization and causes the leaving of formed double-stranded DNA from graphene surface. The electrostatic ssDNA grafting occupies phosphate backbones and particularly leaves the bases available for efficient hybridization. DNA immobilization and hybridization lead to PDI/graphene interfacial property changes, which are monitored by electrochemical impedance spectroscopy and adopted as the analytical signal. The conserved sequence of the pol gene of human immunodeficiency virus 1 is satisfactorily detected via this PDI/graphene platform and shows high reproducibility, selectivity.

Nanoimprinting-induced efficiency enhancement in organic solar cells

The performance of bilayer heterojunction, pentacene and perylene tetracarboxylic diimide organic solar cells (OSC) is dramatically enhanced by performing nanoimprinting on the hole transport layer in which poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanogratings are built. A standard OSC embeded with PEDOT:PSS gratings enables photocarriers to move toward electrodes. In particular, the visualization of morphologies for these heterojunction layers reveals pillar-like grains that are induced by the geometric effect of PEDOT:PSS gratings. Toghther with analyzing absorption and time-resolved photoluminescence spectra, a consistent correlation between OSC performance, photophysical data, and pillar-like morphology has been obtained for the device with imprinted PEDOT:PSS nanogratings.