Tetracarboxylic Diimide Research Articles

Fabrication of aligned microwire arrays of perylene bisimide by micromolding in capillary

In this work, we synthesized a novel perylene tetracarboxylic acid diimides derivative (APBI-G) which shows a strong self-assembling tendency to the semiconducting nano/microwires based on the augmented intermolecular hydrogen bonding interaction. We demonstrate the spinning of continuous thread of APBI-G from the liquid–liquid interface and also the fabrication of patterned nano/microwire arrays using MIMIC (micromolding in capillaries) method. MIMIC-fabricated APBI-G nano/microwires showed the excellent uniaxial orientation, large birefringence, and reproducible electrical conductivity (1.93 ± 0.47 × 10 −6 S cm −1).

Field effects on the statistical behavior of the molecular conductance in a single molecular junction in aqueous solution

We have combined molecular dynamics simulations with first-principles calculations to study electron transport in a single molecular junction of perylene tetracarboxylic diimide (PTCDI) in aqueous solution under external electric gate fields. It is found that the statistics of the molecular conductance are very sensitive to the strength of the electric field. The statistics of the molecular conductance are strongly associated with the thermal fluctuation of the water molecules around the PTCDI molecule. Our simulations reproduce the experimentally observed three orders of magnitude enhancement of the conductance, as well as the temperature dependent conductance, under the electrochemical gates. The effects of the molecular polarization and the dipole rearrangement of the aqueous solution are also discussed.

Hindered Intramolecular Electron Transfer in Room-Temperature Ionic Liquid

Three perylene tetracarboxylic diimide (PDI) compounds, namely, N,N'- di(2-N'',N''-dimethylamino)ethylperylene-3,4:9,10-tetracarboxylic diimide (1), N,N'-di(2-N'',N''-dimethylamino)propylperylene-3,4:9,10-tetracarboxylic diimide (2), and N,N'- dicyclohexyl-1,7-pyrrolidinylperylene-3,4:9,10-tetracarboxylic diimide (3), have been designed and prepared. Their photophysical properties in room-temperature ionic liquid (RTILs) were studied by steady-state absorption and emission spectra and fluorescence lifetime measurements. The intramolecular photoinduced electron transfer from dimethylamine to PDI in 1 and 2 has been efficiently hindered because of the solvation of RTILs. A two-conformation mechanism for the PET in 1 and 2 is proposed, which explains the results of the fluorescence lifetime measurements well. The solvation of RTILs to 3 resembled that of a normal polar organic solvent with polarity larger than that of DMF.

Soluble and Columnar Liquid Crystalline Peropyrenequinones by Coupling of Phenalenones in Caesium Hydroxide

Perylene tetracarboxylic diimides (PTCDIs) 1 are very versatile, stable and synthetically very accessible red dyes with high extinction coefficients, that have, amongst a variety of other applications, found widespread use in molecular optoelectronics, including electrophotography, solar cells and light-emitting diodes. When substituted with appropriate alkyl or trialkylaryl substituents, they exhibit lamellar or columnar liquid crystalline self-assembly, which gives rise to high intermolecular charge carrier mobilities. The columnar liquid-crystalline state is also prominent in the corresponding orange perylene tetracarboxylic tetraalkyl esters (PTCTEs) 2 in which it can be stabilised at room temperature with racemically branched alkyl groups. A key feature of tetracarboxylic perylene derivatives is their intense absorption at relatively long wavelengths (about 525 nm for dialkyl imides and about 475 nm for tetraalkyl esters in solution) with respect to their small chromophore size (which favours solubility), when compared with other relatively stable polycyclic aromatic hydrocarbon (PAH) ACHTUNGTRENNUNGderivatives. Considerable efforts have been undertaken to obtain perylene derivatives that absorb at yet longer wavelengths, whilst maintaining solubility. These approaches include the introduction of arylimidazole moieties, donor substitution in the bay regions, extension of the core in the rylene series and lateral oligomerisation. To shift the absorption maximum to longer wavelengths by a particularly simple approach that maintains the small chromophore size of 1, and to ensure at the same time columnar liquid-crystalline self-assembly at room temperature, we have investigated the known base-induced dehydro-dimerisation of 3-hydroxy-1-phenalenone (3a). The resulting violet dihydroxyperopyrenequinone 4 can be regarded as a homologue of 1 in which both nitrogen atoms have been exchanged for methine moieties (Scheme 1). Since 4 is enolised (no H NMR coupling in alkyl-substituted 4 between the a protons of R with any ring proton), which yields to two fully sp-configured terminal rings, its colour is

Ultrathin n-Type Organic Nanoribbons with High Photoconductivity and Application in Optoelectronic Vapor Sensing of Explosives

Well-defined ultrathin nanoribbons have been fabricated from an amphiphilic electron donor-acceptor (D-A) supramolecule comprising perylene tetracarboxylic diimide as the backbone scaffold to enforce the one-dimensional intermolecular assembly via strong pi-stacking. These nanoribbons demonstrated high photoconductivity upon illumination with white light. The high photoconductivity thus obtained is likely due to the optimal molecular design that enables a good kinetic balance between the two competitive processes, the intramolecular charge recombination (between D and A) and the intermolecular charge transport along the nanoribbon. The photoconduction response has also proven to be prompt and reproducible with the light turning on and off. The photogenerated electrons within the nanoribbon can be efficiently trapped by the adsorbed oxygen molecules or other oxidizing species, leading to depletion of the charge carriers (and thus the electrical conductivity) of the nanoribbon, as typically observed for n-type semiconductor materials as applied in chemiresistors. Combination of this sensitive modulation of conductivity with the unique features intrinsic to the nanoribbon morphology (large surface area and continuous nanoporosity when deposited on a substrate to form a fibril film) enables efficient vapor sensing of nitro-based explosives.

Tuning the Charge-Transport Parameters of Perylene Diimide Single Crystals via End and/or Core Functionalization: A Density Functional Theory Investigation

Perylene tetracarboxylic diimide (PTCDI) derivatives stand out as one of the most investigated families of air-stable n-type organic semiconductors for organic thin-film transistors. Here, we use density functional theory to illustrate how it is possible to control the charge-transport parameters of PTCDIs as a function of the type, number, and positions of the substituents. Specifically, two strategies of functionalization related to core and end substitutions are investigated. While end-substituted PTCDIs present the same functional molecular backbone, their molecular packing in the crystal significantly varies; as a consequence, this series of derivatives constitutes an ideal test bed to evaluate the models that describe charge-transport in organic semiconductors. Our results indicate that large bandwidths along with small effective masses can be obtained with the insertion of appropriate substituents on the nitrogens, in particular halogenated aromatic groups.

Photoconductivity of thin organic films

Thin organic films were deposited on silicon oxide surfaces with golden interdigitated electrodes (interelectrode gap was 2 μm), and the film resistivities were measured in dark and under white light illumination. The compounds selected for the measurements include molecules widely used in solar cell applications, such as polythiophene ( PHT), fullerene ( C 60 ), pyrelene tetracarboxylic diimide ( PTCDI) and copper phthalocyanine ( CuPc), as well as molecules potentially interesting for photovoltaic applications, e.g. porphyrin–fullerene dyads. The films were deposited using thermal evaporation (e.g. for C 60 and CuPc films), spin coating for PHT, and Langmuir–Schaeffer for the layer-by-layer deposition of porphyrin–fullerene dyads. The most conducting materials in the series are films of PHT and CuPc with resistivities 1.2 × 10 3 Ω m and 3 × 10 4 Ω m, respectively. Under light illumination resistivity of all films decreases, with the strongest light effect observed for PTCDI, for which resistivity decreases by 100 times, from 3.2 × 10 8 Ω m in dark to 3.1 × 10 6 Ω m under the light.

Blending induced stack-ordering and performance improvement in a solution-processed n-type organic field-effect transistor

The mobilities of the solution-processed n-type organic semiconductor, N,N′-di((Z)-9-octadecene)-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-e), were dramatically improved (up to 30 times) by blending with electron donors. The reason can be assigned to the facilitated charge transport due to the increased stack-ordering and crystallinity of the spin-coated thin films after blending. This provides a new way to enhance the performance of existing organic semiconductors by intentional blending.

Nickel(ii) and iron(iii) selective off-on-type fluorescence probes based on perylene tetracarboxylic diimide

Two novel "turn-on" fluorescent probes with perylene tetracarboxylic diimide (PDI) as the fluorophore and two different di-(2-picolyl)-amine (DPA) groups as the metal ion receptor (PDI-1 and PDI-2) were successfully synthesized with satisfactory yields. PDI-1 exhibited high selectivity toward Ni(2+) in the presence of various other metal cations including Zn(2+), Cd(2+) and Cu(2+) which were expected to interfere significantly. A 1 : 2 stoichiometry was found for the complex formed by PDI-1 and Ni(2+) by a Job's plot and by non-linear least square fitting of the fluorescence titration curves. By introducing an extra diamino ethylene group between DPA and the phenyl bridge, the receptor was modified and the high selectivity of the sensor toward Ni(2+) shifted to Fe(3+). The enhancement factor of the fluorescence response of PDI-2 to Fe(3+) was as high as 138. The binding behavior of the receptors in these two compounds is affected significantly by the PDI fluorophores. Most interestingly, both Ni(2+) and Fe(3+) are paramagnetic metal ions, which are known as fluorescence quenchers and are rarely targeted with "turn-on" fluorescence probes. This result suggests that PDIs are favorable fluorophores for a "turn-on" fluorescence probe for paramagnetic transition metal ions because of their high oxidation potential.

Photoinduced long-term memory effects in n-type organic perylene transistors

In this paper, the photoexcitation response of high mobility n-type organic field-effect transistors is analyzed. White light exposure of N,N′-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8H) transistors is demonstrated to promote the occurrence of metastable conductance states with very long retention times, similar to what has been previously reported for p-type compounds. Even in the absence of a gate-source voltage VGS, the complete recovery of the initial electrical condition can take up to 20 days. However, the initial state restoring is electrically controllable by the application of a positive VGS. These effects suggest that PTCDI-C8H is an interesting n-type material for the development of light-sensitive organic circuitry.

Heteroepitaxy growth high performance films of perylene diimide derivatives

High performance films of phenyl substituted perylene diimide are obtained by heteroepitaxy growth through Weak Epitaxy Growth technique. As epitaxially grown on the para-sexiphenyl ( p-6P) ordered layers, the N, N′-di-phenyl perylene tetracarboxylic diimide (PTCDI-Ph) grows to form continuous and highly oriented films with large grain size, which possess low density of grain boundary and smooth surface. This quality films bring about improvement of two orders of magnitude in mobility compare to the traditional films, and present relative good air stability. Ambipolar transport behavior was also observed as tuning the thickness of p-6P.

The Importance of Grain Boundaries for the Time-Dependent Mobility Degradation in Organic Thin-Film Transistors

The relationships between organic semiconductor morphology and device stability of organic field-effect transistors (FETs) are very complex and not yet fully understood. Especially for obtaining high-performance, air-stable n-channel FETs, gaining a deep insight into possible degradation mechanisms can help improve their air stability. Here, we investigate the performance and stability of organic n-channel FETs based on solution-grown single-crystalline ribbons of the conjugated semiconductor bis(1H,1H-perfluorobutyl)-dicyano-perylene tetracarboxylic diimide (C3F7CH2−PTCDI-(CN)2). The FETs show an electron mobility of 0.25 cm2/(V s) in air and an on/off ratio up to 1 × 107. Their mobility does not significantly change when devices are stored in air for more than 5 weeks. This excellent air stability stands in contrast to FETs based on thin evaporated polycrystalline films of the same compound that degrade by more than an order of magnitude during the same 5 week period. We attribute this striking difference in air stability to the grain boundaries in the polycrystalline films and discuss different possible degradation mechanisms.

Tailoring Bicomponent Supramolecular Nanoporous Networks: Phase Segregation, Polymorphism, and Glasses at the Solid−Liquid Interface

We study the formation of four supramolecular bicomponent networks based on four linear modules (linkers) bridging melamine via triple hydrogen-bonds. We explore at the nanoscale level the phenomena of polymorphism and phase segregation which rule the generation of highly crystalline nanoporous patterns self-assembled at the solid-liquid interface. The investigated linkers include two systems exposing diuracil groups in the alpha and omega position, naphthalene tetracarboxylic diimide and pyromellitic diimide. In situ scanning tunneling microscopy (STM) investigations revealed that, when blended with melamine, out of the four systems, three are able to form two-dimensional (2D) porous architectures, two of which exhibit highly ordered hexagonal structures, while pyromellitic diimide assembles only into one-dimensional (1D) supramolecular arrays. These bicomponent self-assembled monolayers are used as a test bed to gain detailed insight into phase segregation and polymorphism in 2D supramolecular systems by exploring the contribution of hydrogen-bond energy and periodicity, molecular flexibility, concentration and ratio of the components in solution as well as the effect of annealing via time-dependent and temperature-modulated experiments. These comparative studies, obtained through a joint experimental and computational analysis, offer new insights into strategies toward the bottom-up fabrication of highly ordered tunable nanopatterning at interfaces mediated by hydrogen bonds.

Low-voltage organic n-channel thin-film transistors based on a core-cyanated perylene tetracarboxylic diimide derivative

Using the small-molecule organic semiconductor bis(1 H,1 H-perfluorobutyl)-dicyano-perylene tetracarboxylic diimide, C 3F 7CH 2-PTCDI-(CN) 2, and a low-temperature-processed, high-capacitance gate dielectric based on a phosphonic acid self-assembled monolayer, we have manufactured n-channel thin-film transistors on glass substrates. The transistors operate with low voltages (2 V) and have an electron mobility of 0.04 cm 2/Vs and an on/off ratio of 10 5. By combining C 3F 7CH 2-PTCDI-(CN) 2 n-channel transistors with pentacene p-channel transistors, we have also manufactured low-voltage, low-power organic complementary inverters with good static and dynamic performance.

Organic Thin-Film Solar Cells Using Electron-Donating Perylene Tetracarboxylic Acid Derivatives

Various electron-donating amino groups were introduced into the perylene core of perylene tetracarboxylic acid derivatives (PTCs) to address the potential use in organic solar cells. Broad absorptions of the PTC solutions in the visible to near-infrared (NIR) region suggest that PTCs are promising light-harvesting molecules for solar cells. Electrochemical measurements reveal that the introduction of the electron-donating amino groups makes the energy level of the highest occupied molecular orbital (HOMO) shallow, imparting electron-rich characteristics to the PTCs. The electronic properties of the PTCs are studied on the basis of quantum chemical calculations. The results show that the variation of the amino groups has a significant influence on the HOMO level, while the lowest unoccupied molecular orbital (LUMO) level is relatively sensitive to the electronegativity of the PTC terminal atoms. The PTC thin films exhibit broad absorption bands in the visible to NIR region, as for the PTC solutions, and possess relatively shallow HOMO and LUMO energies that are higher or comparable to those of fullerene C60. These excellent properties encouraged us to employ amine-substituted PTCs as electron donors in a thin film solar cell with C60 as an n-type semiconductor. Photovoltaic devices with a structure of indium tin oxide (ITO)/PTCs/C60/bathocuproine (BCP)/Al were fabricated by spin-coating PTCs on an ITO electrode. The devices with perylene tetracarboxylic acid diimides (PTCDIs), bearing highly basic amino groups (Py-PTCDI, Me2N-PTCDI, and Ph2N-PTCDI), exhibit the higher power conversion efficiencies than those with carbazoyl PTCDI (Cz-PTCDI) and perylene tetracarboxylic acid dianhydrides (PTCDAs). The higher device performance originates from the efficient electron transfer from the PTCs to C60 as the results of the relatively shallow HOMO and LUMO levels of the PTCs bearing the highly basic amino groups. The dependence of the device performance on the PTC film thickness indicates that the introduction of diphenylamino groups on the perylene core suppresses the nonradiative decay of the exciton without decreasing the hole mobility. These results will provide important information for the molecular design of post PTC derivatives.

Effect of molecular packing on interfacial recombination of organic solar cells based on palladium phthalocyanine and perylene derivatives

Planar heterojunction solar cells made of three different perylene tetracarboxylic diimide (PTCDI) derivatives as acceptor and palladium phthalocyanine as donor are demonstrated. Electron-hole pair recombination at donor/acceptor interface was compared for three PTCDI derivative solar cells by optical modeling and the effect of molecular packing of the PTCDI derivatives on charge dissociation is discussed. We observed that PTCDI with hexyl chains has the highest charge separation efficiency among three PTCDI derivatives, leading to a power conversion efficiency of 2.0% in solar cells.

Highly Polarized and Self-Waveguided Emission from Single-Crystalline Organic Nanobelts

Well-defined single-crystalline nanobelts with strong fluorescence were fabricated from a perylene tetracarboxylic diimide molecule modified with specific side-chains that afford flip-flap stacking, rather than the common translated stacking, between the molecules along the long axis of the nanobelt. The nanobelts thus fabricated possess highly polarized, self-waveguided emission, making them ideal candidates for application in nanolasers and other angle-dependent optical nanodevices.

Fluorescent Silica Nanoparticles by Silylation

Shining nanosil: Fluorescent trimethoxysilanes were prepared by the hydrosilylation of N-allyl perylene tetracarboxylic diimides and used for the covalent grafting of silica and silica nanoparticles (see picture). The fluorescent chromophores operate independently at the surface of these particles.

Organic complementary inverters with polyimide films as the surface modification of dielectrics

The organic complementary metal oxide semiconductor (O-CMOS) inverters were integrated with the p-type pentacene-based transistors and n-type N, N′-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI–C 8H 17)-based transistors. Polyimide (PI) films were inserted between the active layers and dielectrics as the role of surface modification. The performances of the O-CMOS including the mobility, on/off ratio, subthreshold slope, threshold voltage, gains, delay time, and leakage current suppression were dramatically enhanced when PI layer was introduced. An ideal O-CMOS inverter with the propagation delay time of 52 μs at 1 kHz was achieved for the device with PI modification layer. The detail mechanism for performance improvement was discussed.

The electrical and dielectrical behavior of n-conducting perylene tetracarboxylic diimide derivatives

A comparison of the electrical characteristics of organic field-effect transistors (OFETs) based on derivatives of the electron-conductor perylene tetracarboxylic diimide (PTCDI) in top-contact configuration is presented. The derivatives used are N,N′-dimethyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiMe-PTCDI), N,N′-diphenyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiPhenyl-PTCDI), N,N′-dimethoxyethyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiMethoxyethyl-PTCDI), N,N′-di(3-pentyl)-3,4,9,10-perylene-tetracarboxylic-diimide (Di3Pentyl-PTCDI), and N,N′-diheptyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiHeptyl-PTCDI). Current/voltage measurements were first performed in situ and later ex situ. Additionally, the effect of annealing and bias stress was probed in situ. A strong influence of the different side groups on the order of magnitude of the electron mobility is revealed, ranging from 4×10−6 cm2/V s for DiMethoxyethyl-PTCDI to 5×10−2 cm2/V s for DiHeptyl-PTCDI. While none of the devices was stable in air after exposition to air, only the DiMe-PTCDI one resumed its functionality after restoring vacuum conditions. The dielectric functions of the derivatives was derived, additionally revealing optical isotropy for all films and varying surface roughness. While DiHeptyl-PTCDI and Di3Pentyl-PTCDI, yielding also the highest electron mobilities, form smooth layers with negligible surface roughness, strong island formation was be observed for DiPhenyl-PTCDI and DiMethoxyethyl-PTCDI, yielding low mobilities. This island growth was also confirmed by atomic force microscopy measurements. Ageing of the samples for several months under ambient conditions leads to increased roughness for the very rough samples. Layers with smooth surface, on the other hand, showed no significant change in the dielectric behavior of the sample.