P-phenylene Vinylene Research Articles

In Situ Monitoring of Mechanofluorescence in Polymeric Nanofibers.

Mechanofluorescent polymers represent a promising class of materials exhibiting fluorescence changes in response to mechanical stimuli. One approach to fabricating these polymers involves incorporating aggregachromic dyes, whose emission properties are governed by the intermolecular distance, which can, in turn, be readily altered by microstructural changes in the surrounding polymer matrix during mechanical deformation. In this study, a mechanofluorescent additive featuring excimer-forming oligo(p-phenylene vinylene) dyes (tOPV) is incorporated into electrospun polyurethane fibers, producing mats of fibers with diameters ranging from 300 to 700nm. The influence of the additive concentration and fiber orientation on the mechanofluorescent response under tensile deformation is investigated. In situ fluorescence spectroscopy and microscopy imaging reveal a strain-dependent change of the fluorescence color from orange to yellow or green, with a more pronounced response in prealigned fibers. Stresses experienced by the nanofibers during elongation are mapped in real-time. The data reveal that forces initially concentrate in fibers that are aligned parallel to the applied strain, and only later redistribute as other fibers once they also align. These findings advance the understanding of force transfer within fibrous polymer mats and are expected to facilitate the development of self-reporting nanofibers for applications in load-bearing devices, wearable technologies, and mechanochromic textiles.

Regioregular Poly(p-phenylene iminoborane): A Strictly Alternating BN-Isostere of Poly(p-phenylene vinylene) with Stimuli-Responsive Behavior.

Incorporation of BN units into π-conjugated organic compounds, as substitutes for specific CC couples, often leads to new hybrid materials with modified physical and chemical properties. Poly(p-phenylene iminoborane)s are derived from well-known poly(p-phenylene vinylene) (PPV) by replacement of the vinylene groups by B=N linking units. Herein, an unprecedented poly(p-phenylene iminoborane) is presented that features a strictly alternating sequence of BN units along the main chain. The synthesis thereof was achieved by AB-type polymerization of a monomer featuring an N and a B terminus. Monodisperse oligomers with up to three BN units in the chain were additionally prepared and structurally characterized. Associated with the introduction of a dipole in the regioregular backbone structure, they display notable fluorescence already in solution and large Stokes shifts, distinct from their previously reported BBNN-sequenced congeners. All compounds show aggregation-induced emission enhancement (AIEE) properties. Computational studies provided evidence for emission from either locally excited (LE) or twisted intramolecular charge transfer (TICT) states. These processes can be optionally addressed by various stimuli, giving rise to dual emission, solvatochromic, thermochromic, and reversible mechanochromic behavior.

Cyano-Substituted Oligo(p-phenylene vinylene) Derivatives with Aggregation-Induced Enhanced Emissions and Mechanofluorochromic Luminescence.

Developing red fluorescence emitters with simple structures via convenient synthetic routes is highly desirable yet challenging. Herein, two novel donor-acceptor-type red emitters, DCFOPV-TPA and SCFOPV-TPA, featuring the intramolecular charge transfer effect were designed by integrating triphenylamine and trifluoromethyl into a CN-substituted oligo(p-phenylene vinylene) backbone. Both chromophores exhibited aggregation-induced enhanced emission and solvatochromic behavior. Moreover, DCFOPV-TPA also displayed reversible mechanofluorochromic properties under external force.

N-Type ion gel gated vertical organic electrochemical transistors based on benzodifurandione-based Oligo(p-phenylene vinylene)s

Organic electrochemical transistors (OECTs) using aqueous gate dielectrics have garnered significant interest for bioelectronic applications. However, their viability for long-term use in neuromorphic computing and synaptic devices is limited due to their short-term functionality. In this study, we synthesize two benzodifurandione-based oligo (p-phenylene vinylene) polymers, BDOPV-TCNVT and ClBDOPV-TCNVT, and investigate their electrochemical transistor properties using quasi-solid-state ion gel-gated vertical OECTs (v-OECTs). Compared to BDOPV-TCNVT, the chlorinated ClBDOPV-TCNVT demonstrates lower frontier molecular orbitals and easier electrochemical doping. The higher volumetric capacitance of as-spun ClBDOPV-TCNVT (1.94 F cm−3) compared to as-spun BDOPV-TCNVT films (1.49 F cm−3) is mainly attributed to the easier ion infiltration resulting from its lower crystallinity with mixed chain orientation. The quasi-solid-state v-OECTs based on both polymers (as-spun) exhibit transconductance (gm) of 0.06–0.08 mS. Following thermal treatments, the gm gradually decreases for both polymers due to enhanced edge-on ordering with tight interchain packing, hindering ion penetration. Despite the poor electrochemical doping by quasi-solid-state ion gel gated dielectrics, the enlarged area and decreased channel length in v-OECTs (compared to parallel OECTs) can enhance the gm. Further optimization of v-OECTs requires tailored material designs specifically suited for efficient vertical charge transport together with ion infiltration.

From monomer to polymer: Controlled synthesis and comprehensive analysis of poly(p-phenylene vinylene) via ROMP

This study focuses on synthesis and evaluation of [2.2] paracyclophane-1,9-diene to produce a soluble poly(p-phenylenevinylene) (PPV) derivative homopolymer using ring-opening metathesis polymerization (ROMP). The resulting homopolymer displayed a narrow polydispersity index (PDI) of 1.22, indicating precise control over polymerization. The PPV derivative exhibited excellent solubility in various organic solvents. Photophysical properties, including optical absorption and fluorescence emission spectra, were investigated to evaluate utilization in optoelectronic devices. Optical band gaps ranged from 2.21 to 2.25 eV for thin films and 2.07 to 2.19 eV for solutions, while the electrochemical band gap, determined by cyclic voltammetry, was 2.37 eV. These materials demonstrated promising fluorescence activity in various solvents and thin films, suggesting potential applications in organic light-emitting diodes (OLEDs) and related optoelectronic devices.

Negative Capacitance Effect Using a Pure Imaginary Electric Mobility Controlled By an Adiabatic Parameter in Thin Film Materials Based On Drude Model

Existence of a pure imaginary mobility of charge carriers in organic polymers materials, precisely the poly p-phenylene vinylene is explored in this work. Indeed, we propose a new model of dynamic equation of particles able to carry electric charges, we introduce a control parameter of the adiabatic evolution combined with a phase difference between the external perturbation of the material and the position of carrier, leading from then on to the non-use of the complex mobility. This model after transformation allowed us to demonstrate the existence of negative capacitance at low and high frequencies in the poly p-phenylene vinylene. Also thanks to this new model, we were able to obtain results in line with the experimental ones, thus confirming the validity of our model

Poly(arylene iminoborane)s, Analogues of Poly(arylene vinylene) with a BN-Doped Backbone: A Comprehensive Study.

Despite the great success of the concept of doping organic compounds with BN units to access new materials with tailored prop-erties, its use in polymer chemistry has only been realized quite re-cently. Herein, we present a comprehensive study of oligo- and poly-(arylene iminoborane)s comprising a back-bone of phenylene or thio-phene moieties, as well as combinations thereof, linked via B=N units. The novel polymers can be regarded as BN analogues of poly-(p-phenylene vinylene) (PPV) or poly(thiophene vinylene) (PTV) or their copolymers, respectively. Our modular syn-thetic approach al-lowed us to prepare four polymers and twelve monodisperse oligo-mers with modulated electronic properties. Alter-nating electron-re-leasing di-aminoarylene and electron-accepting dibo-rylarylene building blocks give rise to a pronounced donor-acceptor character. Effective π-con-ju-ga-tion over the arylene iminoborane back-bone is evidenced by sys-tematic bathochromic shifts of the low-energy UV-vis absorp-tion max-imum with increasing chain length, which is furthermore sup-ported by crystallographic and compu-tational investigations. Further-more, all compounds investigated show emission of visible light in the solid state and aggregation-induced emission (AIE) behavior, due to the presence of partially flexible linear B=N linkages in the back-bone.

Co-Self-seeding: A facile approach to generate heterogeneous π-Conjugated Fiber-Like comicelles with tunable Length, composition and morphology

Co-self-seeding approach of living crystallization-driven self-assembly (CDSA) enables the generation of fiber-like micelles with a π-conjugated core of tunable length/composition/ morphology with appealing photophysical and photochemical properties. However, our understanding on the co-self-seeding strategy in the preparation of fiber-like comicelles containing a heterogeneous π-conjugated core is limited owing to very rare reports associated to this recently emerging strategy. Herein, we report that polydisperse comicelles containing a heterogeneous OPE9/OPV5 (OPE = oligo(p-phenylene ethynylene), OPV = oligo(p-phenylene vinylene), the subscripts indicate the exact number of repeat unit of OPE and OPV segments) core can be formed from the mixture of OPE9-b-P2VP56 and OPV5-b-PNIPAM47 (P2VP = poly(2-vinylpyridine), PNIPAM = poly(N-isopropylacrylamide), the subscripts denote the degree of polymerization) with different mass ratios of OPE9-b-P2VP56 to OPV5-b-PNIPAM47 (MOPE9/MOPV5) by crystallization-driven co-self-assembly via heating/cooling protocol. Subsequently, by co-self-seeding from the seed comicelles obtained by the fragmentation of as-prepared polydisperse comicelles, apparent continuous (gradient) and segmented (block) fiber-like comicelles containing a heterogeneous OPE9/OPV5 core of controlled length/composition/morphology can be generated with varying annealing temperature and MOPE9/MOPV5. Co-self-seeding from pairs of separated seed micelles of OPE9-b-P2VP56 and OPV5-b-PNIPAM47 with different MOPE9/MOPV5 also can give apparently continuous and segmented fiber-like comicelles containing a heterogeneous OPE9/OPV5 core. These two co-self-seeding approaches have some common and different characteristics. It is found that for these samples with the MOPE9/MOPV5 = 1/1 and 2/1, the Ln of comicelles obtained from seed comicelles showed much sharper increase with the increase of temperature relative to the Ln of comicelles generated from mixed seed micelles as the temperatures were above 70 °C. On the contrary, for the MOPE9/MOPV5 = 5/1, both sets of samples showed very similar trend of dependence of Ln of resulting comicelles on the annealing temperature. These results revealed that both packing modes and mass ratios (MOPE9/MOPV5) of seed (co)micelles affected the co-self-seeding behavior.

Nowhere to run: oligo (p-phenylene vinylene) kills oral intracellular bacteria photodynamically

Bacterial infections pose a severe threat to human health due to the exacerbation of antibiotic resistance and intracellular bacterial infections. Research suggests that oligo(p-phenylene vinylene) (OPV), commonly employed in the manufacture of organic solar batteries, can help address this issue. This study demonstrates the ability of OPV to target and sterilize intracellular Porphyromonas gingivalis and methicillin-resistant Staphylococcus aureus (MRSA) photodynamically. Most notably, OPV specifically targets bacteria without affecting healthy cells under dark conditions. Its chemical composition includes a conjugated backbone and ionic imidazole side chains, which allow OPV to bind to cell membranes. Furthermore, dental blue light curing lamps may excite OPV. Compared with antibiotics and traditional photosensitizers, OPV proves to be a potentially superior solution to eradicate intracellular microbial infections, both in fundamental research and clinical applications.

Enabling Quick Response to Nitrogen Dioxide at Room Temperature and Limit of Detection to Ppb Level by Heavily n-Doped Graphene Hybrid Transistor.

Sensitive detection of nitrogen dioxide (NO2) is of significance in many areas for health and environmental protections. In this work, we developed an efficient NO2 sensor that can respond within seconds at room temperature, and the limit of detection (LOD) is as low as 100 ppb. Coating cyano-substituted poly(p-phenylene vinylene) (CN-PPV) films on graphene (G) layers can dope G sheets effectively to a heavy n state. The influences of solution concentrations and annealing temperatures on the n-doping effect were investigated in detail. The CN-PPV-G transistors fabricated with the optimized parameters demonstrate active sensing abilities toward NO2. The n-doping state of CN-PPV-G is reduced dramatically by NO2, which is a strong p-doping compound. Upon exposure to 25 ppm of NO2, our CN-PPV-G sensors react in 10 s, indicating it is almost an immediate response. LOD is determined as low as 100 ppb. The ultrahigh responding speed and low LOD are not affected in dry air. Furthermore, cycling use of our sensors can be realized through simple annealing. The superior features shown by our CN-PPV-G sensors are highly desired in the applications of monitoring the level of NO2 in situ and setting immediate alarms. Our results also suggest that transfer curves of transistors can react very promptly to the stimulus of target gas and, thus, are very promising in the development of fast-response sensing devices although the response values may not reach maximum as a tradeoff.

Insights on the Molecular Orientation of Oligo(p-phenylene vinylene) Derivatives with Alkyl Chains in Langmuir Films

One of the oligo(p-phenylene vinylene) derivatives having alkyl chains, OPV-1, is known to form characteristic rod-shaped nanoaggregates on the water surface, and thin films with aligned nanoaggregates can be obtained by the Langmuir–Blodgett (LB) technique. Although the molecular aggregation and orientation of the “conjugated rings part” in the LB films have already been investigated, analysis of the detailed molecular structure involving the “alkyl chains” is left behind. In the present study, to reveal the role of the alkyl chains in the molecular aggregation in Langmuir films prior to the LB transfer, infrared (IR) external reflection spectroscopic measurements on the water surface are carried out. It has been revealed that not only the conjugated rings of OPV-1 but also the alkyl chains with an ordered conformation are lying on the water surface. The characteristic orientation is found to be kept on a solid substrate even after the LB transfer by IR p-polarized multiple-angle incidence resolution spectrometry (pMAIRS). In addition, pMAIRS was first employed for analyses of the biaxial orientation in the LB films, and the molecular orientations for the conjugated rings and the alkyl chains were quantitatively evaluated from both in-plane and out-of-plane perspectives.

Parametric extraction and internal analysis of fullerene-based polymer bulk heterojunction solar cell

This paper present device model simulation describing the current-voltage characteristics of polymer/fullerene bulk heterojunction solar cell. In the research paper an organic photovoltaic device with PPV/PCBM [poly (2-methoxy-5-{3’,7’-dimethyloctyloxy}-p-phenylene vinylene) and {6,6}- phenyl C61-butyric acid methyl ester] was simulated via Silvaco TCAD 2-D simulation tool. PCBM acts as acceptor and PPV is donor. The models used to simulate the device were Langevin for recombination, s.binding and a.singlet. Simulation of these type of devices is an vital approach to project and predict the cell performance. Under the illumination of one sun (AM 1.5) the simulated organic cell showed a short circuit current density (JSC) of 28 A/m2, open circuit voltage (VOC) of 0.84 Volt and a fill factor (FF) of 52.51%, the resulting maximum efficiency of the PPV/PCBM organic solar cell is 1.22%.

Mechanochromism of polyurethane based on folding—unfolding of cyano-substituted oligo(p-phenylene) vinylene dimer

Mechanochromism of polyurethane based on folding—unfolding of cyano-substituted oligo(p-phenylene) vinylene dimer

Solvent-induced MultiStimuli-Responsive properties of cyano-substituted Oligo(p-phenylene vinylene) derivatives

Stimuli-responsive luminescent materials with controllable photophysical properties have attracted much attention because of their potential applications in smart materials and devices. Through the incorporation of electron-donating (NPh3) and electron-withdrawing (CN) functionalities, two donor-acceptor luminophores C4OPV-TPA and C8OPV-TPA bearing two different alkyl chain lengths were prepared and fully characterized. Although both C4OPV-TPA and C8OPV-TPA exhibited similar luminescence and AIEE effects in solution with intramolecular charge-transfer (ICT) transition, remarkable differences were observed in the self-assemble state. Specifically, precipitation of C4OPV-TPA into toluene and CH2Cl2, respectively, afforded two distinctly crystallines, with one in orange color (O-state) and the other in red color (R-state). Notably, C4OPV-TPA in O-state exhibited stimuli-responsive behaviors in solid state, which were ascribed to the formation of an inclusion complex with toluene molecules. Under thermal heating and mechanical grinding, toluene was released from crystal lattice of luminophore accompanied with red-shifted emission spectra. The molecular packing of C4OPV-TPA in R-state, on the other hand, adopted stronger H-aggregates without inclusion of CH2Cl2 molecules, which was further investigated by X-ray diffraction. These excellent optical properties enabled C4OPV-TPA serve as a fluorescent ink for thermal-responsive data storage device.

Flexible organic solar cell to power modern cardiac pacemakers: Versatile for all age groups, skin types and genders

Bio-medical electronic components execute an vital part in medical services. Powering these devices is a task. Thus, the biomedical electronic devices which are able to self-harvest and store power are in huge demand. Present pacemakers are powered by batteries which have limited volume for energy packing and are compulsory to be changed. This needs a surgical intervention and is costly, with attachment of complications and risk. The objective of this paper is to validate if a subdermal PPV-PCBM [poly (2-methoxy-5-{3′,7′-dimethyloctyloxy}-p-phenylene vinylene) and {6,6}-phenyl C61—butyric acid methyl ester] active layer bulk heterojunction (BHJ) organic photo-voltaic (OPV) device could power a cardiac pacemaker. Power yield of 0.05 milliWatts (mW), 0.45 milliWatts & 2.1 milliWatts for African, Asian & Caucasian skin tones are gained at 2-millimeter implementation depth, acceptable to operate cardiac pacemaker demanding approximate power of 10 microWatts. Additionally, results correspondingly display higher output power is generated if the skin is thinner and brighter.

Linear and macrocyclic oligo(p-phenylene iminoboranes) with ferrocenyl side groups - observation of selective, non-templated macrocyclization.

A series of linear oligo(p-phenylene iminoboranes), which are BN-modified congeners of oligo(p-phenylene vinylenes), featuring pendent ferrocene groups have been prepared. Stoichiometric reaction of a bis-silylamine with a bisborane led to selective formation of an unprecedented macrocycle, without the use of a template.

Living Crystallization-Driven Self-Assembly of Oligo(p-phenylene vinylene)-Containing Block Copolymers: Impact of Branched Structure of Alkyl Side Chain of π-Conjugated Segment

Living Crystallization-Driven Self-Assembly of Oligo(p-phenylene vinylene)-Containing Block Copolymers: Impact of Branched Structure of Alkyl Side Chain of π-Conjugated Segment

Poly(p-phenylene vinylene) incorporated into carbon nanostructures

Composites of poly(p-phenylene vinylene) (PPV) and different carbon nanostructures, such as fullerene C60, multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), graphene oxide (GO), and graphene nanoplatelets (GNPLs), were produced by Wittig’s soluble precursor procedure in solutions containing dispersed particles of carbon nanomaterials. These composites were investigated using infrared and Raman spectroscopy, scanning and transmission electron microscopy, thermogravimetry analysis, adsorption/desorption of N2 measurement, and electrochemistry. Composites are produced in the form of nanostructural porous materials. A significant increase in the BET (Brunauer–Emmett–Teller) surface is observed for composites in comparison to unmodified PPV. The highest BET surface area of 125 m2·g−1 was obtained for the PPV/SWCNT composite. Compared to pristine PPV, composites also exhibit higher thermal stability. The effect of the content of composite components on their electrochemical properties was also investigated. The electronic interaction between components of composite significantly affects their electrochemical properties, particularly in the case of oxidation processes. PPV incorporated into network of carbon nanostructures exhibit two well separated oxidation steps. The carbon component is responsible for the shift of the PPV reduction and oxidation processes toward less negative and less positive potentials, respectively, significantly lowering the energy of the band gap.Graphical abstract

Antimicrobial and Photoantimicrobial Activities of Chitosan/CNPPV Nanocomposites.

Multidrug-resistant bacteria represent a global health and economic burden that urgently calls for new technologies to combat bacterial antimicrobial resistance. Here, we developed novel nanocomposites (NCPs) based on chitosan that display different degrees of acetylation (DAs), and conjugated polymer cyano-substituted poly(p-phenylene vinylene) (CNPPV) as an alternative approach to inactivate Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Chitosan’s structure was confirmed through FT-Raman spectroscopy. Bactericidal and photobactericidal activities of NCPs were tested under dark and blue-light irradiation conditions, respectively. Hydrodynamic size and aqueous stability were determined by DLS, zeta potential (ZP) and time-domain NMR. TEM micrographs of NCPs were obtained, and their capacity of generating reactive oxygen species (ROS) under blue illumination was also characterized. Meaningful variations on ZP and relaxation time T2 confirmed successful physical attachment of chitosan/CNPPV. All NCPs exhibited a similar and shrunken spherical shape according to TEM. A lower DA is responsible for driving higher bactericidal performance alongside the synergistic effect from CNPPV, lower nanosized distribution profile and higher positive charged surface. ROS production was proportionally found in NCPs with and without CNPPV by decreasing the DA, leading to a remarkable photobactericidal effect under blue-light irradiation. Overall, our findings indicate that chitosan/CNPPV NCPs may constitute a valuable asset for the development of innovative strategies for inactivation and/or photoinactivation of bacteria.

The effect of positional disorder and the Beer-Lambert law in organic photovoltaics : A kinetic Monte Carlo simulation analysis.

It is urgent to address climate change by radically changing our energy sources. Organic photovoltaics (OPVs) are a competitive clean energy emerging technology and will undoubtedly have a market niche in a world that needs to take advantage of every possible type of renewable energy. Recent studies have brought relevant improvements on internal efficiency, focusing on two properties at the interface: energetic disorder and bending. However, how positional disorder affects internal efficiency is still an open question. Here, we show that positional disorder is desired at the interface, but only up to a threshold value of 0.2 nm for poly p-phenylene vinylene. Using a kinetic Monte Carlo simulator, we realized that not enough excitons were reaching the interface, and introduced the Beer-Lambert law of attenuance to correct it. Furthermore, we realized that the same disorder that facilitates charge separation at the interface diminishes exciton and charge mobility in bulk, so we propose here a new morphology for the active layer of OPVs. Our suggestion implicates in better overall performance, improving not just the internal but the overall cell efficiency.