Structure Of Organic Layers Research Articles

Phonon Directionality Impacts Electron-Phonon Coupling and Polarization of the Band-Edge Emission in Two-Dimensional Metal Halide Perovskites.

Two-dimensional metal halide perovskites are highly versatile for light-driven applications due to their exceptional variety in material composition, which can be exploited for the tunability of mechanical and optoelectronic properties. The band-edge emission is defined by the structure and composition of both organic and inorganic layers, and electron-phonon coupling plays a crucial role in the recombination dynamics. However, the nature of the electron-phonon coupling and what kind of phonons are involved are still under debate. Here we investigate the emission, reflectance, and phonon response from single two-dimensional lead iodide microcrystals with angle-resolved polarized spectroscopy. We find an intricate dependence of the emission polarization with the vibrational directionality in the materials, which reveals that several bands of low-frequency phonons with nonorthogonal directionality contribute to the band-edge emission. Such complex electron-phonon coupling requires adequate models to predict the thermal broadening of the emission and provides opportunities to design polarization properties.

P‐213: Management of light extraction and viewing angle behavior of cavity‐driven top‐emitting OLEDs with buckling patterns

Different scale of buckling patterns (1D ordered and 2D random) was employed for light extracting layer of top‐emission OLED. In the case of 2D random structure, thermal expansion and shrink of organic layers produced quasi‐periodicity. Improvement of TOLED efficiency as well as viewing angle behavior was analyzed in terms of the scale of periodic patterns and optical cavity effect. Methods in this work could be utilized as an effective tool for managing microcavity‐driven performance of TOLED.

Sputter-cleaning modified interfacial energetic and molecular structure of DNTT thin film on ITO substrate

The effect of natural electrode contamination on interfacial energetic, structure and morphology of π-conjugated organic molecular layers were studied by depositing dinapthothienothiophene (DNTT) thin films of varying thickness on indium-tin-oxide (ITO) substrates and by using photoelectron spectroscopy, atomic force microscopy and X-ray reflectivity techniques. The DNTT thin film on unclean-ITO surface shows a smaller threshold ionization potential (by ∼0.4 eV) compared to the film on clean-ITO one. A molecule–substrate interaction, present in the DNTT/clean-ITO system, gives rise to an interfacial dipole and charge transfer, presumably through flat-lying seed-layer at the interface. On further deposition, the interfacial coverage increases, while the molecules on top of the seed-layer take different orientation (mostly edge-on) to form highly-dewetted fibrous-islands of very high-thickness but very low-coverage. Overall, the growth of DNTT film on clean-ITO surface is layer-plus-island-like or Stranski–Krastanov-type. On the other hand, the contamination layer at the DNTT/unclean-ITO interface is found to act as a spacer layer, which reduces the intimate molecule–substrate interaction and also the roughness to give rise an edge-on ordered island-like or Volmer–Weber-type film-growth with reduced hole injection barrier (by ∼0.2 eV) and better (almost double) film-coverage to make it a more efficient hole injector compared to the clean interface one.

Research Progress of Organic Field-Effect Transistor Based Chemical Sensors.

Due to their high sensitivity and selectivity, chemical sensors have gained significant attention in various fields, including drug security, environmental testing, food safety, and biological medicine. Among them, organic field-effect transistor (OFET) based chemical sensors have emerged as a promising alternative to traditional sensors, exhibiting several advantages such as multi-parameter detection, room temperature operation, miniaturization, flexibility, and portability. This review paper presents recent research progress on OFET-based chemical sensors, highlighting the enhancement of sensor performance, including sensitivity, selectivity, stability, etc. The main improvement programs are improving the internal and external structures of the device, as well as the organic semiconductor layer and dielectric structure. Finally, an outlook on the prospects and challenges of OFET-based chemical sensors is presented.

P‐4.4: Multifunctional Laminated Organic Passivation Layer on InSnZnO Thin‐Film Transistors for Enhanced Reliability

To improve the stability of the ZnO‐based thin‐film transistors (TFTs) in multiple environments, we propose a new multifunctional laminated organic passivation layer (MLO PVL) structure for ITZO TFTs. This MLO PVL structure is composed of a self‐assembled monolayer (SAM) and an ultraviolet (UV) absorber‐modified polydimethylsiloxane (PDMS) layer, which provides the functionality of both passivation layers at the same time. The SAM film could be prepared by vapor‐phase treatment, while the UV‐absorber‐modified PDMS layer could be fabricated using the spin‐coating method. Thus, the MLO PVL could be manufactured through a low‐temperature and low‐cost process. Compared to the unpassivated devices, the MLO‐passivated ITZO TFTs exhibit better properties, such as an on‐off current ratio (Ion/Ioff) of up to 8.99×109, a field‐effect mobility of 19.55 cm2V−1s−1, and a subthreshold swing (SS) down to 100 mV/dec. Furthermore, the MLO‐passivated ITZO TFTs showed an outstanding improvement in the bias stress stability and UV light illumination stress stability with negligible threshold voltage shifts in both positive bias stress (PBS) and positive bias illumination stress (PBIS) tests. This new passivation structure provides a potential strategy for improving the stability of ZnO‐based TFTs.

Impact of Brittle Deformation on Pore Structure Evolution in Shale: Samples Collected from Different Fault Positions

Tectonic deformation has an important influence on the pore structure and physical properties of shale, and different parts of the same structural style also have great differences. In this study, eight shale samples were collected from two different faults based on the distance from each fault. Comparative analysis of the micro/nanopore structural characteristics and physical properties of these samples was carried out by scanning electron microscopy, liquid nitrogen adsorption, and carbon dioxide adsorption. The results show that as brittle deformation is enhanced (from far away from the fault to inside the fault), the number of organic pores decreases overall, and the connectivity of microfractures and different pore types increases. The total pore volume and total pore specific surface area of shale both increase, the pore volume of mesopores decreases by 31%, and the macropores increase rapidly by 29%. The storage capacity of shale-related folds is higher than that of shale in faults, which is more conducive to the adsorption of shale gas. The permeability of shale in faults is higher than that of shale-related folds, which is more conducive to the seepage and migration of shale gas. The organic layer structure, which is a unique and very rare microstructure at the shale fault site (under shear), was observed inside the fault. It is believed that the organic matter in the shale at the fault site has transformed from the amorphous state at the initial stage of formation to the orientation of the aromatic lamellae to stretching and extension to an increase in the pore size and the enhancement of connectivity. In addition, inorganic nanoparticles were also observed at the fault site. Both structures are important for the small pores in the fault and the increase in reservoir space. When the fault forms a closed environment or tectonic activity ceases in the later period, the early fault location likely becomes a potential high-quality hydrocarbon generation reservoir. These results help improve the understanding of the physical properties of shale reservoirs and shale gas reservoir migration within fault structures and are of great significance for shale gas exploration, development, and prediction.

Magnetic Properties and Magnetodielectric Effect in (C6H5CH2NH3)2[CuCl4] with Organic-Inorganic Hybrid Layered Structure

Metal Organic Frameworks (MOFs) are a group of multiferroic candidates that exhibit various optical, electrical, magnetic, and structural properties depending on the type of organic cations, transition metals and halogen elements, and their molar ratio. (C6H5CH2NH3)2[CuCl4] (BZACC), one of the MOF materials, has a special hybrid layered structure of organic and inorganic layers. Magnetic property measurement showed that BZACC exhibits weak in-plane ferromagnetism below the Curie point (TC) of 10.25 K and the saturated magnetic moment of 1 µB per formula unit at 2 K. When the magnetic field is less than 0.1 T along the c axis, it exhibits weak antiferromagnetism below 8 K. From the measurement of the dielectric constant with external magnetic field, we observed a maximum magnetodielectric (MD) effect of 0.4% at 2 K. Furthermore, it was found that the magnetic-field dependence of the MD effect is similar to that of the second derivative of magnetization with respect to magnetic field. We suggest that the observed MD effect is the consequence of the magnetic-field-induced spin structure change in the inorganic layer, which induces the change in the interlayer magnetic coupling and, as a result, induces the change in the dielectric constant by the applied magnetic field.

Влияние термообработки на структуру органических слоев, содержащих углеродные нанотрубки

Влияние термообработки на структуру органических слоев, содержащих углеродные нанотрубки

A new luminescent organic-inorganic hybrid material based on cadmium iodide

The title compound,1,4-diazoniabicyclo[2.2.2]octane-tetraiodocadmate(II), (C6H14N2)[CdI4], is self-assembled into alternating organic and inorganic layered structure. The anionic layer consists of isolated [CdI4]2− tetrahedra placed parallel to (102) plane. The organic part is made up of 1,4-diazabicyclo[2.2.2]octane cations [(DABCOH2)2+] that link to the anionic layer via N–H⋯I hydrogen bonds. The hydrogen-bonding capability was interpreted by Hirshfeld surface and fingerprint plot analysis. The vibrational properties have been studied via FT-IR spectroscopy with calculated semi-empirical PM3 mode. The main interest for this family of materials lies in the strong excitonic luminescence at room temperature. For that, a full optical study was carried out by optical absorption and photoluminescence.

Strong bioinspired HPA-rGO nanocomposite films via interfacial interactions for flexible supercapacitors

Flexible supercapacitors with excellent performance are needed to meet the increasing demand for wearable and flexible electronics. The challenge remains to design exceptionally flexible supercapacitors with remarkable electrochemical properties. Natural nacre shows outstanding fracture toughness due to its alternating inorganic and organic layered structure and abundant interfacial interactions, providing an inspiration for designing flexible supercapacitors. Herein, we demonstrated nacre-inspired flexible supercapacitors via synergistic interfacial interactions of π-π conjugated bonds, hydrogen bonding, and electrostatic interaction between halloysite (HA)-polyaniline (PANI) nanocomposites and graphene oxide (GO) nanosheets. The resultant nacre-inspired HPA-rGO nanocomposite films demonstrate strong tensile strength (351.9 MPa), high electrical conductivity (397.0 S cm−1), and long cycle life with ~ 85% of capacitance retention after 10,000 cycles. Furthermore, the assembled all-solid-state supercapacitors (ASSSs) based on bioinspired HPA-rGO electrodes can not only display extraordinary flexibility with no decay of capacitance behavior after 5000 bending cycles, but also deliver remarkable mass energy density up to 16.3 Wh kg−1, outperforming other flexible graphene-based supercapacitors. This nacre-inspired strategy for designing flexible electrodes provides an avenue for the next-generation power source in the fields of aerospace and smart wearable electronics.

Fabrication of Bevel Structures by Means of the Spatial Gradient of Ion Dose in Ar Gas Cluster Ion Beam and Its Unique Characteristics

AbstractFor the accurate characterization of organic layered structures, a novel methodology to fabricate the bevel structure is suggested by utilizing the argon cluster ion‐beam sputtering (Ar GCIB), namely, little chemical damage to the organic material and a spatial gradient of ion dose in the sub‐millimeter range. The Ar GCIB sputtering settings are elaborately tuned on the basis of the Faraday/target current, and its optimization condition for preparing the bevel structure is determined. As a standard sample, an organic bevel structure is manufactured from the organic layered structure of C60/boron subphthalocyanine chloride/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) films, and their molecular distributions and chemical/electronic structures are investigated using various analytical techniques, including X‐ray photoelectron spectroscopy, secondary ion mass spectrometry, Auger electron spectroscopy, Raman spectroscopy, and matrix‐free ultraviolet‐laser desorption/ionization. Every experimental result demonstrates clearly that the bevel structure prepared by the method keeps its original molecular distribution and chemical structure. On the contrary, conventional etching techniques such as Ar+ ion beam, focused ion beam, and ion milling cause critical distortion in chemical information without exception. Ultimately, the suggested method, a unique way to prepare a damage‐free organic bevel structure, widens the availability of analytical techniques that have limitations in spatial or depth resolution.

A comprehensive investigation of organic active layer structures toward high performance near-infrared phototransistors

Tin phthalocyanine (SnPc) is a kind of organic semiconductor material with excellent absorbing characteristic in near-infrared (NIR) region but rarely applied in photosensitive organic field-effect transistors (PhOFETs). Here, a series of SnPc based PhOFETs with different active layer structures were fabricated and characterized for the purpose of making a systematic investigation of organic active layer structure toward NIR phototransistors. Among the sample devices with different active layer structures, the tri-layer planar heterojunction structure of Device C exhibits high photoresponsivity of 2686.1 mA/W and the photosensitivity is up to 104. The tri-layer hybrid planar-bulk heterojunction configuration of Device D also possesses excellent overall performance, whose photoresponsivity reaches 1894.7 mA/W and photosensitivity is up to 5925. Meanwhile, the detectivity remains at the level of 1012 Jones. After a comprehensive investigation of different organic active layer structures, some useful design principles for NIR phototransistors are obtained. While the mobility of SnPc is relatively low, the photosensitive performance of the devices can be improved to various extent by applying planar and hybrid planar-bulk heterojunction configuration. Given the similar features of some organic NIR materials, we believe that the device design concepts we used for SnPc can be helpful to guiding and designing higher performance NIR phototransistors based on other organic materials.

Force-field parameters for beryllium complexes in amorphous layers.

Unknown force-field parameters for metal organic beryllium complexes used in emitting and electron transporting layers of OLED structures are determined. These parameters can be used for the predictive atomistic simulations of the structure and properties of amorphous organic layers containing beryllium complexes. The parameters are found for the AMBER force field using a relaxed scan procedure and quantum-mechanical DFT calculations of potential energy curves for specific internal (angular) coordinates in a series of three Be complexes (Bebq2; Be(4-mpp)2; Bepp2). The obtained parameters are verified in calculations of some molecular and crystal structures available from either quantum-mechanical DFT calculations or experimental data. Graphical Abstract Beryllium complexes in amorphous layersᅟ.

Chlorine adlayer-templated growth of a hybrid inorganic–organic layered structure on Au(111)

Growth of a hybrid inorganic–organic layered structure on the Au(111) surface using a one-step solution growth is reported. The hybrid structure is consist of 4,4′-bipyridine [4,4′-BiPyH2]2+ cations, Cl anions and Au adatoms, provided from substrate by means of the adsorbate-induced surface phase transition of a surface reconstruction. Its surface and bulk structures were characterized by scanning tunneling microscopy (STM), secondary ion mass spectrometry (SIMS), and Raman spectroscopy. STM results reveal growth of the first [4,4′-BiPyH2]2+ layer on top of the p3×3R30° chlorine overlayer formed on the Au(111) surface. These two layers are found to provide a platform for a following three-dimensional growth facilitated by hydrogen bonding, aurophilic and π–π stacking interactions.

Structure of Rigid Polymers Confined to Nanoparticles: Molecular Dynamics Simulations Insight.

Nanoparticles (NPs) grafted with organic layers form hybrids able to retain their unique properties through integration into the mesoscopic scale. The organic layer structure and response often determine the functionality of the hybrids on the mesoscopic length scale. Using molecular dynamics (MD) simulations, we probe the conformation of luminescent rigid polymers, dialkyl poly(p-phenylene ethynylene)s (PPE), end-grafted onto a silica nanoparticle in different solvents as the molecular weights and polymer coverages are varied. We find that, in contrast to NP-grafted flexible polymers, the chains are fully extended independent of the solvent. In toluene and decane, which are good solvents, the grafted PPEs chains assume a similar conformation to that observed in dilute solutions. In water, which is a poor solvent for the PPEs, the polymer chains form one large cluster but remain extended. The radial distribution of the chains around the core of the nanoparticle is homogeneous in good solvents, whereas in poor solvents clusters are formed independent of molecular weights and coverages. The clustering is distinctively different from the response of grafted flexible and semiflexible polymers.

Aggregation of Cyanine Dye Molecules in the Near Fields of Plasmonic Nanoparticles Excited by Pulsed Laser Irradiation

Influence of laser irradiation on the supramolecular structure of thin organic dye layers is shown to depend on the presence of metal nanoparticles supporting localized surface plasmon resonance. Silver nanoparticles with the average size of 13 nm were produced on the sapphire substrate via physical vapor deposition under UHV conditions. The thus obtained granular silver film was spin-coated by monocarbocyanine dye. The samples were characterized by vis-NIR spectroscopy, SEM, and AFM. It is established that in the presence of silver nanoparticles pulsed laser irradiation at the wavelength of 532 nm leads to an increase of the relative concentration of the J-aggregates of the monocarbocyanine dye molecules, while on the bare sapphire substrate only the destruction of the dye molecules was observed.

Polarization-dependent NEXAFS study of adsorption of long-chain surfactants on mechanically milled iron powder

In this work we have demonstrated the possibility of using the polarization-dependent NEXAFS spectra to study the structure of organic layers at the surface of powdered materials with plate-like shaped particles. The polarization dependence of the NEXAFS spectra may be easily obtained by just changing the angle between the X-ray beam direction and the substrate onto which the powder particles are set. For the first time, we have carried out a detailed study of the surfactant layers (n-perfluorononanoic and stearic acid), which are formed at the surface of iron plate-like particles under mechanical milling of iron powder with an addition of corresponding surfactants. The surfactant molecules are predominantly oriented perpendicular to the surface of the mechanically milled particles. Such orientation is similar to the arrangement of the molecules in the layers formed under equilibrium conditions, e.g. deposition from solutions. The changes in the chemical environment occurring in the molecule tails (defluorination or dehydrogenation) under mechanochemical treatment, do not result in a significant change in the molecular orientation and disordering of the adsorbed layer.

47.4: Distinguished Paper: Realization of Outstandingly High Efficacy White OLED by Controlling Evanescent Mode and Wide Angular Incident Light

AbstractOptimization of angular light distribution in organic layer and light extraction structure based on high refractive index substrate were investigated. Due to advanced optical design for decreasing waveguide and evanescent modes, white OLED device with outstandingly high efficacy of 133 lm/W at 1,000 cd/m2 was realized.

Mechanochemical Synthesis of [Zn3(C2O4)3(4,4'-bipy)4] and its Reorganization at High Temperatures

Abstract The metal organic layered structure catena-(bis(μ2-4,4'-bipyridine)-tris(μ2-oxalato)-bis(4,4'-bipyridine)-tri-zinc(ii)) ([Zn3(C2O4)3(4,4'-bipy)4]) was synthesized mechanochemically applying three different routes. The synthesis succeeded by i) simultaneously neat grinding the three starting materials zinc acetate dihydrate, oxalic acid dihydrate and 4,4'bipyridine, ii) grinding two compounds and adding the third afterwards, independent of the sequence. The products were characterized using powder X-ray diffraction, Raman spectroscopy, gas adsorption measurements, and scanning electron microscopy. Temperature-dependent synchrotron XRD measurements revealed that the monoclinic structure of [Zn3(C2O4)3(4,4'-bipy)4] rearranges reversibly to a higher ordered orthorhombic structure [Zn(C2O4)(4,4'-bipy)] at high temperatures.

Current Density and Spectrum Analysis of Voltage Withstanding Phosphorescent Organic Light-Emitting Diodes with Thick Organic Layer Structure

Current Density and Spectrum Analysis of Voltage Withstanding Phosphorescent Organic Light-Emitting Diodes with Thick Organic Layer Structure