Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Dielectric Function of Undoped and Doped Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene-vinylene] by Ellipsometry in a Wide Spectral Range.

ABSTRACT: Ellipsometric measurements in a wide spectral range (from 0.05 to 6.5 eV) have been carried out on the organic semiconducting polymer, poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene-vinylene] (MDMO-PPV), in both undoped and doped states. The real and imaginary parts of the dielectric function and the refractive index are determined accurately, provided that the layer thickness is measured independently. After doping, the optical properties show the presence of new peaks, which could be well-resolved by spectroscopic ellipsometry. Also for the doped material, the complex refractive index, with respect to the dielectric function, has been determined. The broadening of the optical transitions is due to the delocalization of polarons at higher doping level. The detailed information about the dielectric function as well as refractive index function obtained by spectroscopic ellipsometry allows not only qualitative but also quantitative description of the optical properties of the undoped/doped polymer. For the direct characterization of the optical properties of MDMO-PPV, ellipsometry turns out to be advantageous compared to conventional reflection and transmission measurements.

SUBMITTER: Gasiorowski J

PROVIDER: S-EPMC3809355 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Synthesis and Photophysical and Electroluminescent Properties of Poly(1,4-phenylene-ethynylene)-<i>alt</i>-poly(1,4-phenylene-vinylene)s with Various Dissymmetric Substitution of Alkoxy Side Chains.

Project description:The synthesis and characterization of a set of conjugated polymers, poly(1,4-phenylene-ethynylene)-alt-poly(1,4-phenylene-vinylene)s (PPE-PPVs), with a dissymmetrical configuration (partial or total) of alkoxy side chains is reported. Five new polymers bearing octyloxy and/or octadecyloxy side chains at the phenylene-ethynylene and phenylene-vinylene segments, respectively, were obtained. Two symmetrical substituted polymers were used for comparison. Polymers with weight-average molecular weight, Mw, up to 430 000 g/mol and degree of polymerization between 17 and 322 were obtained by a Horner-Wadsworth-Emmons olefination polycondensation reaction of the respective luminophoric dialdehydes and bisphosphonates. As expected, identical conjugated backbones in all polymers results in very similar photophysical response in dilute solution, with high fluorescence quantum yields between 50% and 80%. In contrast, the thin film properties are dependent on the combinatorial effects of side chain configuration, molecular weight, and film thickness parameters, which are the basis of the resulting comparison and discussion.

| S-EPMC4730230 | biostudies-literature

Controlling Morphology and Aggregation in Semiconducting Polymers: The Role of Solvents on Lasing Emission in Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene].

Project description:Systematic experiments were performed to investigate solvent-dependent morphology and aggregation of the semiconducting polymer film poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), which was span-cast from nonaromatic strong polarity solvents tetrahydrofuran (THF), trichloromethane (TCM) and aromatic weak polarity solvents chlorobenzene (CB), toluene, and p-xylene. The results indicated that the conformation of the spin-cast MEH-PPV films with weak aggregation such as THF and TCM demonstrated excellent lasing emission performances because of inhibiting the fluorescence quenching induced by bi-molecule process. The Atomic Force Microscope (AFM) images confirmed the distinct morphologies of the spin-cast MEH-PPV films. The amplified spontaneous emission (ASE) was investigated in a simple asymmetric slab planar waveguide structure by methods of variable stripe length (VSL) and shifting excitation stripe (SES). The amplified spontaneous emission (ASE) experiments confirmed the distinct polymer chain conformation. The conformation, which preserved from the spin-cast process, indicated the distinct interactions between solvents and MEH-PPV polymer chains. The pure film spectra were performed to confirm the effect of distinct conformation on the material energy level. This work provides insights into the morphology and aggregation effect of the spin-cast polymer films on the performances of lasers.

| S-EPMC5551749 | biostudies-other

Poly(1,4-phenylene vinylene) Derivatives with Ether Substituents to Improve Polymer Solubility for Use in Organic Light-Emitting Diode Devices.

Project description:New ether-substituted poly(1,4-phenylene vinylene) (PPV) derivatives were synthesized via Horner-Emmons coupling. The structures of the monomers and the resultant oligomers were confirmed by 1H and 13C NMR spectroscopies. The molecular weights of the oligomers were characterized by gel permeation chromatography, giving the number-average and weight-average molecular weights and the corresponding polydispersity indices. Measurements of UV-vis absorption and fluorescence were used to characterize the optical properties of the oligomers. Estimation of the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels and other electrochemical characteristics of the oligomers were investigated by cyclic voltammetry. Dialkyl and dialkoxy PPV oligomers were also prepared and characterized following the same instrumental methods used for the ether-substituted oligomers, providing a known reference system to judge the performance of the new conjugated oligomers. Devices were fabricated to analyze the electroluminescent characteristics of the oligomers in organic light-emitting diodes.

| S-EPMC6941186 | biostudies-literature

Adsorption of 1,4-phenylene diisothiocyanate onto the graphene oxide sheets functionalized with polydiphenylamine in doped state.

Project description:Adsorption processes of 1,4-phenylene diisothiocyanate (PDITC) on two new platforms of the type graphene oxide (GO) sheets and GO layers functionalization with polydiphenylamine (PDPA) are studied by Raman scattering and photoluminescence (PL). An interaction in solid state phase of the two constituents, i.e. PDITC and GO sheets, and a deposition of PDITC onto the PDPA functionalized GO layers, respectively, by the drop casting method, were performed. In the first case, it is shown that interaction in solid state phase of GO with PDITC leads to an intercalation of the organic compound between GO sheets simultaneously with the appearance of the o-thiocarbamate groups, that induces: (i) an enhancement of the PDITC Raman lines situated in the 400-800 and 1000-1300 cm-1 spectral ranges, (ii) a change in the ratio between the relative intensities of the two Raman lines peaked at 1585 and 1602 cm-1 accompanied by an up-shift in the case of the second line and (iii) a down-shift of the PDTIC PL band from 502 to 491 nm. Using cyclic voltammetry, an electrochemical functionalization of the GO layers with PDPA doped with H3PMo12O40 heteropolyanions takes place, as demonstrated by Raman scattering and FTIR spectroscopy. The presence of the amine groups in the molecular structure of the doped PDPA functionalized GO layers induces a chemical adsorption of PDITC on this platform, when the thiourea groups appear simultaneously with o-thiocarbamate groups. A chemical mechanism is proposed to take place at the interface of the GO sheets and the doped PDPA functionalized GO layers, respectively, with PDITC.

| S-EPMC6700158 | biostudies-literature

Synthesis and folding behaviour of poly(p-phenylene vinylene)-based ?-sheet polychromophores.

Project description:This contribution describes the design and synthesis of ?-sheet-mimicking synthetic polymers comprising distinct poly(p-phenylene vinylene) (PPV) and poly(norbornene) (PNB) backbones with multiple turns. The rod-coil-coil-rod tetrablock copolymers, synthesized using ring-opening metathesis polymerization (ROMP) and featuring orthogonal face-to-face ?-? stacking and phenyl/perfluorophenyl interactions, show persistent folding both in bulk and at the single molecule level, irrespective of the number of ?-turns. Single molecule polarization studies reveal that the copolymers are more anisotropic than the corresponding homopolymers. Examination of the spectral signatures of the single molecules shows a dominant emissive chromophore in the linked materials compared to the homopolymer. The lack of significant spectral changes of the folded materials along with the existence of a dominant emission spectrum supports the proposed structure of well-aligned, minimally-interacting chromophores. Utilization of this reliably folding, phenyl/perfluorophenyl functionality could provide an extremely useful tool in future functional materials design.

| S-EPMC6385485 | biostudies-literature

[2.2.2.2]Paracyclophanetetraenes (PCTs): cyclic structural analogues of poly( <i>p</i>‑phenylene vinylene)s (PPVs).

Project description:Background: Poly( p-phenylene vinylene)s ( PPVs) and [2.2.2.2]paracyclophanetetraene ( PCT) are both composed of alternating π-conjugated para-phenylene and vinylene units. However, while the former constitute a class of π-conjugated polymers that has been used in organic electronics for decades, the latter is a macrocycle that only recently revealed its potential for applications such as organic battery electrodes. The cyclic structure endows PCT with unusual properties, and further tuning of these may be required for specific applications. Methods: In this article, we adopt an approach often used for tuning the properties of PPVs, the introduction of alkoxy (or alkylthio) substituents at the phenylene units, for tuning the optoelectronic properties of PCT. The resulting methoxy- and methylthio-substituted PCTs, obtained by Wittig cyclisation reactions, are studied by UV-vis absorption, photoluminescence, and cyclic voltammetry measurements, and investigated computationally using the visualisation of chemical shielding tensors (VIST) method. Results: The measurements show that substitution leads to slight changes in terms of absorption/emission energies and redox potentials while having a pronounced effect on the photoluminescence intensity. The computations show the effect of the substituents on the ring currents and chemical shielding and on the associated local and global (anti)aromaticity of the macrocycles, highlighting the interplay of local and global aromaticity in various electronic states. Conclusions: The study offers interesting insights into the tuneability of the properties of this versatile class of π-conjugated macrocycles.

| S-EPMC10445936 | biostudies-literature

Dielectric properties of semi-insulating Fe-doped InP in the terahertz spectral region.

Project description:We report the values and the spectral dependence of the real and imaginary parts of the dielectric permittivity of semi-insulating Fe-doped InP crystalline wafers in the 2-700 cm-1 (0.06-21 THz) spectral region at room temperature. The data shows a number of absorption bands that are assigned to one- and two-phonon and impurity-related absorption processes. Unlike the previous studies of undoped or low-doped InP material, our data unveil the dielectric properties of InP that are not screened by strong free-carrier absorption and will be useful for designing a wide variety of InP-based electronic and photonic devices operating in the terahertz spectral range.

| S-EPMC5544691 | biostudies-other

Effects of Neutral, Anionic and Cationic Polymer Brushes Grafted from Poly(para-phenylene vinylene) and Poly(para-phenylene ethynylene) on the Polymer's Photoluminescent Properties.

Project description:The conformation of a fluorescent polymer, in the solid state or in solution, plays a critical role in the polymer's fluorescent properties. Thus, grafted side chains on a fluorescent polymer can directly influence its optical properties. In this study, the effect of grafted polymeric side chains on the photoluminescent properties of poly(para-phenylene vinylene) (PPV) and poly(para-phenylene ethynylene) (PPE) were investigated. Low- and high-molecular-weight grafts of neutral poly(n-butyl acrylate), cationic poly(trimethylaminoethyl methacrylate) and anionic poly(sulfopropyl acrylate) were grafted onto PPVs and PPEs, and the effect of the grafting on the graft copolymer's absorption and emission wavelengths, the fluorescence intensity and the quantum yield were studied. The results indicate that in the case of the ionic grafts, contrary to the expectations, the polymers have a reduced quantum yield. This contrasts with the copolymers with uncharged side chains (PnBA), where a major increase in the quantum yield is seen for the self-quenching conjugated pristine polymers. These results reinforce that the molecular conformation of the polymer in a solid or solution plays a critical role in fluorescent polymers photoluminescent properties.

| S-EPMC9322352 | biostudies-literature

Triptycene diols: a strategy for synthesizing planar π systems through catalytic conversion of a poly(p-phenylene ethynylene) into a poly(p-phenylene vinylene).

Project description: Not available

| S-EPMC3496247 | biostudies-literature

TD-DFT Simulation and Experimental Studies of a Mirrorless Lasing of Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)].

Project description:In this work, we investigate the TD-DFT simulation, optical, and mirrorless laser properties of conjugated polymer (CP) Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], also known as (PFO-co-PPV-MEHB) or ADS125GE. TD-DFT calculations were performed for three monomer units with truncated tails using time-dependent density functional theory (TD-DFT) calculations. The calculations showed a highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) structure and a very high oscillator strength of 6.434 for the singlet-singlet transition at 374.43 nm. Experimentally, the absorption and fluorescence spectra were examined at various concentrations in verity of solvents, such as benzene, toluene, and hexane. The experimental results obtained in hexane were comparable with theoretical UV-VIS spectra calculated under vacuum. Amplified spontaneous emission (ASE) spectra peaked at approximately 509 nm for CO PFO-co-PPV-MEHB in solution and were obtained at suitable concentrations and pump energies. Additionally, the photochemical stability of this CP and coumarin (C510) were compared. Time-resolved spectroscopy (TRS) studies with a sub-nanosecond resolution were performed for the CO under various pump energies. These results showed the excited state dynamics and single-pass optical gain of CO PFO-co-PPV-MEHB.

| S-EPMC8125217 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data