Perylenetetracarboxylic Diimide Research Articles

TiO2(110) Charge Donation to an Extended π-Conjugated Molecule.

The surface reduction of rutile TiO2(110) generates a state in the band gap whose excess electrons are spread among multiple sites, making the surface conductive and reactive. The charge extraction, hence the surface catalytic properties, depends critically on the spatial extent of the charge redistribution, which has been hitherto probed by small molecules that recombine at oxygen vacancy (Ovac) sites. We demonstrate by valence band resonant photoemission (RESPES) a very general charge extraction mechanism from a reduced TiO2(110) surface to an extended electron-acceptor organic molecule. Perylene-tetra-carboxylic-diimide (PTCDI) is not trapped at Ovac sites and forms a closely packed, planar layer on TiO2(110). In this configuration, the perylene core spills out the substrate excess electrons, filling the lowest unoccupied molecular orbital (LUMO). The charge transfer from the reduced surface to an extended π-conjugated system demonstrates the universality of the injection/extraction mechanism, opening new perspectives for the coupling of reducible oxides to organic semiconductors and supported catalysts.

Morphology-controlled self-assembly of an amphiphilic perylenetetracarboxylic diimide dimer-based semiconductor: from flower clusters to hollow spheres

Morphology-controlled self-assembly of a perylenetetracarboxylic diimide dimer was achieved in THF–H2O mixtures by changing the volume ratios of the solvents. The nanostructures showed a hydrazine-sensing response.

Synthesis and aggregation properties of a series of dumbbell polyhedral oligosilsesquioxane-perylene diimide triads

A series of perylenetetracarboxylic diimide compounds connected with POSS groups have been synthesized and their solid state emission properties are investigated.

Shift of absorption energy during thin dye film growth: interpretation by geometric models of the growth morphology

We measure absorption spectra of two different perylene molecules in thin films with thicknesses varied between 1 and 30nm physical vapor deposited on glass substrates. Atomic force microscopy (reveals the formation of crystallized needles for N, N`-dimethyl perylene tetracarboxylic acid diimide and amorphous round-shaped islands for 1,6,7,12-tetrachloro-N,N`-dimethyl perylene tetracarboxylic. For both molecules, a spectral shift of the lowest energy transition to lower energies was observed with increasing film thickness. Common models taking electric fields, electronic coupling or exciton confinement into account cannot completely describe the observed spectral shift. Here we show that the experimental values can be fitted with an advanced layering model based on the energetic difference between bulk and interface/surface materials. In contrast to the known simple d−1 model, which describes the energetic shift for the special case of a layer-by-layer growth, we extend this idea to other film morphologies.

A Highly Selective and Turn‐on Fluorescent Probe for Fe3+ Ion Based on Perylene Tetracarboxylic Diimide

AbstractWe have demonstrated a turn‐on fluorescent sensor 6 for detection of Fe3+ based on photo‐induced electron transfer (PET) mechanism. The probe comprises a perylene tetracarboxylic diimide (PDI) fluorophore and two bis((1,2,3‐triazol‐4‐yl)methyl)amine (DTA) moieties as the metal ion receptors. It exhibits high selectivity toward Fe3+ over various other metal ions in CH3CN/H2O (1:1, V/V). The binding stoichiometry for 6‐Fe3+ complexes has been determined to be 1:2 by a Job plot of fluorescence. The association constant between 6 and Fe3+ was estimated to be 1.04×1010 (mol/L)−2 by Benesi‐Hildebrand equation.

Solvent-dependent nanostructures of gels of a Gemini surfactant based on perylene diimide spacer and oligostyrene tails

We discuss the thermo-reversible gelation of a non-ionic Gemini surfactant with perylene tetracarboxylic diimide (PTCDI) as the spacer and oligostyrene as the tails, with cyclohexane, toluene, cis-decalin and trans-decalin. The gel with trans-decalin shows a morphology that is distinctly different from those of other solvents. As is usually seen with Gemini surfactants, vesicular morphology is observed in the case of gels using cyclohexane, toluene and cis-decalin, with a wall thickness of about 40nm. The trans-decalin gel shows a fibrous morphology, and these fibers exhibit an eaves-trough type of folding as was seen before with other systems that we studied (Dahan and Sundararajan, 2014; Khanna et al., 2009). X-ray diffraction and UV–Vis spectroscopy indicate that the molecular packing is more ordered in the case of trans-decalin gels. In addition, the storage modulus (G′) of the trans-decalin gels is an order of magnitude higher than those of gels from the other three solvents. Unlike the other reported cases of gels with either perylene diimide derivatives or Gemini surfactants, gelation occurs in the present work, without any hydrogen bonding moieties or charge centers in the structure of the molecule studied here.

Cation-induced self-assembly of an amphiphilic perylene diimide derivative in solution and Langmuir–Blodgett films

A novel amphiphilic perylenetetracarboxylic diimide (PDI) derivative, N-(4′-benzo-15-crown-5-ether)-N-hexyl-1,7-di(4-tert-butyl-phenoxy)perylen-3,4,9,10-tetracarboxylic diimide (15C5PDI), has been synthesized and characterized. Dimerization of 15C5PDI is induced in CHCl3 solution with the present of K+, resulting in the formation of the slipped co-facial J-aggregates, as revealed by absorption and fluorescence spectroscopies. Analysis of the surface pressure–area (π–A) isotherms and spectral change for the monolayer formed at the air/water interface, disclosed that 15C5PDI molecules adopted the H-type aggregation mode with a face-to-face configuration and edge-on orientation on both the surface of pure water and K+ aqueous solution. Consequently, a particularly interesting fluorescence emission change from “switch-on” to “switch-off” could be observed upon aggregation that was accompanied by a transformation from strongly fluorescent J-type into non-fluorescent H-type packing of the 15C5PDI dyes. Depending mainly on the coordination bonding between 15-crown-5-ether groups and K+ ions, one dimensional nanofibrils formed on the surface of the K+ aqueous solution with a more closely arrangement of 15C5PDI molecules relative to those on pure water subphase revealed by the π–A isotherms and atomic force microscopy (AFM) images. X-ray diffraction studies indicate that the film crystallinity and general molecular order in the Langmuir–Blodgett (LB) films deposited from the KCl solution are improved effectively in comparison with those from pure water subphase. Furthermore, the conductivity of the LB films prepared in K+ solution is more than ca. 1 order of magnitude higher than those from water.

High-Efficiency Sorbent for Dyes Based on Cellulose Resin Crosslinked with Perylene Tetracarboxylic Diimides

The novel cellulose resin crosslinked with perylene tetracarboxylic diimides 3 was synthesized and its structure was characterized by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electronmicroscopy (SEM), etc. Dyes adsorption experiments of polymer 3 suggested that it exhibited excellent adsorption capacities for tested four cationic and anionic dyes [Orange G sodium salt (OG), Brilliant ponceau 5R (BP), Methylene blue (MB), and Crystal violet (CV)]. The adsorption capacities for OG, BP, MB, CV were as high as 1.04, 1.21, 1.14, and 0.96 mmol/g, respectively. The adsorption processes obeyed the pseudo second-order model and followed the Langmuir isotherm equation. The adsorption processes were exothermic and spontaneous. The pH = 2 ˜ 12 made slight influences on adsorption capacities of polymer 3 for dyes. It was supposed that the adsorption mechanism was not only the electrostatic forces and hydrogen bond but also the π-π stacking interaction playing an important role in the adsorption processes.

Versatile threshold voltage control of OTFTs via discontinuous pn-heterojunction formation

We demonstrate the versatility of the threshold voltage control for organic thin-film transistors (OTFTs) based on formation of discontinuous pn-heterojunction on the active channel layer. By depositing n-type dioctyl perylene tetracarboxylic diimide molecules discontinuously onto base p-type pentacene thin films (the formation of the discontinuous pn-heterojunction), a positive shift of the threshold voltage was attained which enabled realizing a depletion-mode transistor from an original enhancement-mode pristine pentacene transistor. Careful control of the threshold voltage based on this method led assembling a depletion-load inverter comprising a depletion-mode transistor and an enhancement-mode transistor connected in series that yielded tunable signal inversion voltage approaching 0V. In addition, the tunability could be applied to improve the program/erase signal ratio for non-volatile transistor memories by more than 4 orders of magnitude compared to reference memory devices made of pristine pentacene transistors.

A simple and sensitive label-free fluorescent approach for protein detection based on a Perylene probe and aptamer

Highly sensitive detection of proteins is of great importance for effective clinical diagnosis and biomedical research. However, so far most detection methods rely on antibody-based immunoassays and are usually laborious and time-consuming with poor sensitivity. Here, we developed a simple and ultra-sensitive method to detect a biomarker protein–thrombin by taking advantage of the fluorescent probe Perylene tetracarboxylic acid diimide (PTCDI) derivatives and thrombin aptamer. The water-soluble dye PTCDI shows strong fluorescence in buffer solution for the existence of free dye monomer, but becomes weak after aggregation through self-assembly on nucleic acid aptamer. In the presence of thrombin, it specifically binds to thrombin aptamer which causes the conformational transition between aptamer and PTCDI and results in a significant fluorescence recovery. The results showed that as low as 40pM of thrombin could be detected by this method. The high sensitivity of the developed sensing system mainly attributes to the ultra-sensitivity of the fluorescence intensity changes of PTCDI. With the specificity of aptamer, the assay exhibited high selectivity for thrombin against three other proteins (bovine serum albumin, lysozyme, mouse IgG) and 1% diluted fetal bovine serum. The detection method might be extended to sensitive detection of a variety of proteins for its advantages of isothermal conditions required, simple and rapid without multiple separation and washing steps.

Supramolecular organogels based on perylenetetracarboxylic diimide trimers linked with benzenetricarboxylate

Two new perylenetetracarboxylic diimide (PDI) derivatives, namely, trimer 1 and trimer 2, composed of three PDI units with different tail groups, are prepared. Solubility of these two trimers is significantly different due to the different tail groups. The aggregation behavior of these two compounds in solution was investigated using absorption and fluorescence spectra. The results indicate that both trimers 1 and 2 can form large molecular aggregates via an intermolecular process in either good solvent or poor solvent. Trimer 1 can form gel in a mixed solvent of methanol and tetrahydrofuran (THF), while trimer 2 can only form gel in non-polar solvents, such as hexane and toluene. This can be ascribed to the multiple long alkyl chains in trimer 2, which have introduced extra hydrophobic interactions besides the π–π interactions between the molecules of trimer 2. The morphology examination of the dried gel of trimer 1 by atomic force microscopy (AFM) reveals simply long fibers. But, the dried gel of timer 2 shows network-like morphology, which can be ascribed to the hydrophobic interactions between the multiple alkyl chains.

Perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate in wine.

We report the application of perylenetetracarboxylic diimide (PTCDI) nanowires for sensing ethyl acetate. The conductivity of the crystalline nano/microwires increases quickly and selectively in the presence of ethyl acetate vapor, but not with water, acid and alcohol vapors, suggesting that the nanowires of PTCDI may be used for monitoring ethyl acetate during a wine manufacturing process.

Iron(III) selective fluorescence probe based on perylene tetracarboxylic diimide

Responses of organic fluorophore, perylenediimide derivative N,N′-di[3-[2-(3-thienyl)ethyl]phenyl]perylene-3,4,9,10-bis-(dicarboxyimide) (PDI1) was investigated in polymer matrix of polyvinyl chloride (PVC) by emission spectrometry. Its response to Fe(III) ions was evaluated in terms of the effect of pH. The properties of time dependent response, reversibility, limit of detection, linear concentration range for the metal ion and repeatability characteristics of the sensing element also have been studied. The offered sensor exhibited remarkable fluorescence intensity quenching at pH 6.0 in the concentration range of 1 × 10−6 to 2.5 × 10−3 M Fe(III) ions. The reproducibility of the sensor membrane was investigated by alternately changing the solution between 1 × 10−4 M Fe(III) in Na2HPO4 (4 × 10−2 M) and NaH2PO4 buffer (2 × 10−3 M).

Discontinuous pn-Heterojunction for Organic Thin Film Transistors

Utilization of discontinuous pn-oragnic heterojunction is introduced as a versatile method to improve charge transport in organic thin film transistors (OTFTs). The method is demonstrated by depositing n-type dioctyl perylene tetracarboxylic diimide (PTCDI-C8) discontinuously onto base p-type pentacene OTFTs. A more pronounced impact of the discontinuous upper layer is obtained on the transistor performances when thinner base layers are employed; a >100-fold enhancement in hole mobility and a >20 V shift in threshold voltage are achieved after applying PTCDI-C8 discontinuously onto 2 nm thick pentacene thin films. Local surface potential measurements (Kelvin-probe force microscopy) and temperature-dependent transport measurements (77–300 K) reveal that the interfacial dipole formed at the pn-heterostructures effectively dopes the base pentacene films p-type and leads to a reduction in transport activation energy.

Morphology and Conductivity of Self-Assembled Pyrene-Perylenetetracarboxylic Diimide Dyad

One perylenetetracarboxylic diimide (PDI) derivatives (PDI 1) linked with pyrene by flexible chain at the bay positions was synthesized and the molecular structure was characterized by 1H NMR, MALDI-TOF mass spectra as well as elemental analysis. The molecular self-assembly were prepared from solution via a slow evaporation of solvent. The properties of these molecular aggregates were studied by electronic absorption and fluorescence spectra. The morphologies and structures were examined by scanning electronic microscopy (SEM) and X-ray diffraction (XRD) techniques. The conducting properties were evaluated by currentvoltage (IV) measurements. The results revealed highly ordered structure for these molecular self-assembly. The thin solid film fabricated from these molecular self-assembly show an electric conductivity as high as 4.85 × 10-4 S cm-1 under the ambient light, which means this compound might be used as a semiconductor in nanoelectronics.

A Facile Method to Preparation of Amphiphilic Perylene Tetracarboxylic Diimide/ZnS Hybrid Nanocomposites and Improved Semiconducting Property

A self-assembled film of an amphiphilic perylene tetracarboxylic diimide derivative (N-hexane-N'-(1-phenyl-4-aminoethanol)-1,7-di (4-tert-butylphenoxy) perylene-3,4;9,10-tetracarboxylate diimide, HH-PDI) has been used as the organic template to produce the first example of monodispersed nanoparticles of HH-PDI/ZnS composites. The HH-PDI pure film and HH-PDI/ZnS nanocomposites were characterized by UV-vis absorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and current-voltage (I-V) measurements. Experimental results revealed the film crystallinity and general molecular order for HH-PDI molecules in the nanocomposites are improved effectively in comparison with those in the pure film due to the introduction of ZnS nanocrystals. The electrical conductivity of the HH-PDI/ZnS nanocomposites (6.6×10-5 S cm-1) is more than ca. 2 order of magnitude higher than that of (3.6×10-7 S cm-1). The present result provides an efficient way to improve the performance of organic semiconductors through introducing inorganic semiconducting nanocrystals.

Covalently linked perylenetetracarboxylic diimide dimers and trimers with rigid "J-type" aggregation structure.

Covalently linked perylenetetracarboxylic diimide (PDI) dimers (D1 and D2) and trimers (T1 and T2) with slipped “face-to-face” stacked structure are prepared and their molecular structures are characterized by 1H NMR, MALDI-TOF mass spectroscopy and elemental analysis. The rigid molecular structures of these compounds make it easier to establish a direct correlation between the aggregate structure and the photophysical properties. The minimized molecular structures of these compounds reveal that they are all “face-to-face” stacked aggregates with large longitudinal displacement. Their absorption spectra show red-shifted bands, suggesting the presence of “J” type excitonic coupling between the PDI subunits in these compounds. However, their steady state and time resolved fluorescence spectra revealed that the emission from the “excimer-like” states dominates the fluorescence of these compounds, this is similar to that of “H-type” aggregates and may be ascribed to the “face-to-face” stacked structure. In the fluorescence spectra of these compounds, a minor “J-type” emission can be identified for the compounds with a relatively large longitudinal displacement. An increase in the number of subunits in one aggregate from 2 to 3 also brings about distinctive changes in their photophysical properties, which can be ascribed to the changes in the stacking structure caused by the steric hindrance.

Thermo-reversible gelation of rod-coil and coil-rod-coil molecules based on poly(dimethyl siloxane) and perylene imides and self-sorting of the homologous pair.

Organogels with perylene derivatives and phthalocyanines reported in the literature so far involve self-assembly promoted by hydrogen bonds, in addition to aromatic and van der Waals interactions. Although the self assembly of these types of molecules without a hydrogen bonding group in the structure occurs in solution or during crystallization, the gelation studies reported so far incorporated a hydrogen bonding pair of the type N-H···O=C in the structure of the molecule. We present a case of thermo-reversible gelation without a hydrogen bonding group in the structure of (1) a coil-rod-coil molecule based on perylenetetracarboxylic diimide (PTCDI) and poly(dimethyl siloxane) (PDMS) and (2) a rod-coil molecule with perylene dicarboxylic imide (PDI) and PDMS. However IR spectroscopy shows the presence of multiple types of hydrogen bonding between the solvents and the gelator molecules. In addition, publications so far on gelation of perylene diimide based molecules involve groups attached to both imide nitrogens and with or without substitution in the bay position. We discuss here the gelation with a Mono-substituted perylene imide. The PDMS segment was attached to one side of PDI (Mono-PDMS) or to both imide nitrogens of PTCDI (Di-PDMS). The Mono-PDMS is an inverse macromolecular surfactant applicable to non-aqueous systems, and the Di-PDMS is a Gemini surfactant. The PDMS segment that we attached to PTCDI here is longer than most substituents used by other authors. These molecules gel propylamine, as well as mixed solvents of hexane-water and diisopropylamine-water. Both hexane and diisopropylamine dissolve Mono-PDMS and Di-PDMS at room temperature and addition of water results in precipitation. However, heating the solution to about 70 °C, adding water (5-15 wt%) and slowly cooling the solution, lead to gelation. The Di-PDMS forms fibers which are not flat but curved as an eaves trough. The Mono-PDMS forms hollow spheres. Although the Mono-PDMS and Di-PDMS are a homologous pair, blends of these do not show molecular intercalation during gelation, but self-sort. The fibers of Di-PDMS based gels encapsulate the spheres of the Mono-PDMS based gels.

Iron(III) Selective Fluorescence Probe Based on Perylene Tetracarboxylic Diimide

Iron(III) Selective Fluorescence Probe Based on Perylene Tetracarboxylic Diimide

Self-assembled organic monolayers on epitaxial graphene with enhanced structural and thermal stability.

Scanning tunnelling microscopy and X-ray reflectivity are used to characterize adlayers of perylenetetracarboxylic diimide (PTCDI) deposited on epitaxial graphene (EG) on SiC(0001). PTCDI adopts a herringbone structural phase on EG/SiC that can accommodate sub-5 nm voids with molecularly defined boundaries and isolated molecular vacancies at room temperature. The PTCDI monolayer remains intact up to substrate temperatures of ~260 °C, thus demonstrating enhanced thermal stability compared to previously studied perylene derivatives on EG/SiC.