Backbone Structure Effect on the Thermoelectric Properties of IDT-Based p-Type Conjugated Polymers.

Four conjugated polymers are synthesized through indacenodithiohene (IDT) unit copolymerized with thiophene and thiophene derivatives. Indacenodithiohene-co-thieno[3,2-b]thiophene (IDT-TT) and indacenodithiohene-co-trans-1,2-di(2-thienyl)ethylene (IDT-TVT) exhibit better charge transport mobilities than indacenodithiohene-co-thiophene (IDT-T) and indacenodithiohene-co-3,4-ethoxylene dioxythiophene (IDT-EDOT), and also display superior thermoelectric properties after doping. Theoretical calculations suggest that IDT-EDOT and IDT-TVT have better coplanarities; the inferior performance for IDT-EDOT might be due to its low molecular weight. Meanwhile, it is worth mentioning that via the synergistic effect of two dopants (CN6CP, CuTFSI), the electrical conductivities of the polymers are further improved. The XPS data shows that the coordination interaction between copper ion and the cyano groups of CN6CP introduces cupric ions into the polymer films, which leads to the increase of the doping ratio.

High-Performance Polymer Solar Cells Achieved by Introducing Side-Chain Heteroatom on Small-Molecule Electron Acceptor.

Side chains of photovoltaic materials play an important role in determining charge transport property, film morphology, and the corresponding device performance. In this work, two new acceptor materials, ATT-6 and ATT-7 with different side chains, m-hexylphenyl and m-hexyloxyphenyl on the indacenodithiophene, are designed and synthesized for applications in non-fullerene polymer solar cells. ATT-7 shows a higher absorption coefficient, increased crystallinity, and improved electron mobility in comparison with ATT-6. Using wide-bandgap polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)] (PBDB-T) as donor, optimized devices based on PBDB-T:ATT-7 and PBDB-T:ATT-6 delivers power conversion efficiencies of 10.30% and 8.39%, respectively. The higher performance of ATT-7-based device can be attributed to efficient exciton dissociation, reduced bimolecular recombination, and enhanced and balanced charge carrier mobilities. These results indicate that side-chain modification is an easy but efficient way in the design of high-performance non-fullerene acceptors.

Interface engineering of semiconductor/dielectric heterojunctions toward functional organic thin-film transistors.

Interface modification is an effective and promising route for developing functional organic field-effect transistors (OFETs). In this context, however, researchers have not created a reliable method of functionalizing the interfaces existing in OFETs, although this has been crucial for the technological development of high-performance CMOS circuits. Here, we demonstrate a novel approach that enables us to reversibly photocontrol the carrier density at the interface by using photochromic spiropyran (SP) self-assembled monolayers (SAMs) sandwiched between active semiconductors and gate insulators. Reversible changes in dipole moment of SPs in SAMs triggered by lights with different wavelengths produce two distinct built-in electric fields on the OFET that can modulate the channel conductance and consequently threshold voltage values, thus leading to a low-cost noninvasive memory device. This concept of interface functionalization offers attractive new prospects for the development of organic electronic devices with tailored electronic and other properties.

The configuration, solvatochromism and metallo-responses of two novel cyano-containing oligo(phenylene-vinylene) derivatives.

Two novel cyano-containing oligo(phenylenevinylene) (OPV) derivatives have been designed and synthesized. Photophysical and sensing properties of the two compounds were studied. Such studies reveal the intramolecular charge transfer process between cyano groups and OPV core. The results showed that the alkyl difference of substituted OPV leads to the changes of molecular configuration and metallo-response of two compounds.

Water-soluble fluorescent conjugated polymers and their interactions with biomacromolecules for sensitive biosensors.

Over the past decades, water-soluble conjugated polymers (CPs) have gained increasing attention as optical platforms for sensitive detection of biomacromolecules (DNA, protein and cell) due to the amplification of fluorescent signals. To meet the requirement for high throughput assays, chip and microarray techniques based on CPs have also been developed. Very recently, fluorescence imaging in vivo and at the cellular level have also been successfully accomplished using these water-soluble CPs. In this tutorial review, we provide a brief review of the synthesis and optical properties of CPs, focusing especially on their applications in biosensors and cell imaging.

Construction and photophysical properties of organic-inorganic nanonetworks based on oligo(phenylenevinylene) and functionalized gold nanoparticles.

Novel organic-inorganic nanonetworks of oligo(phenylenevinylene) (OPV) and gold nanoparticles (GNPs) have been synthesized by the amine-based epoxide ring-opening reaction. The resulting OPV-GNPs nanocomposites exhibit homogeneous and well-defined interfaces between the organic ligands and the inorganic nanoparticles, thereby promoting efficient electronic interfacial interaction between the two constituents. The functionalized gold nanoparticles serve as chemical reagents for the construction of nanohybrids, while the epoxide-terminated OPV acts as linkage between gold nanoparticles. The new architecture provides a facile methodology for fabrication of novel organic-inorganic nanohybrids under relatively mild conditions, which facilitates further applications of hybrid materials.

Current rectification in temperature-responsive single nanopores.

Herein we demonstrate a fully abiotic smart single-nanopore device that rectifies ionic current in response to the temperature. The temperature-responsive nanopore ionic rectifier can be switched between a rectifying state below 34 degrees C and a non-rectifying state above 38 degrees C actuated by the phase transition of the poly(N-isopropylacrylamide) [PNIPAM] brushes. On the rectifying state, the rectifying efficiency can be enhanced by the dehydration of the attached PNIPAM brushes below the LCST. When the PNIPAM brushes have sufficiently collapsed, the nanopore switches to the non-rectifying state. The concept of the temperature-responsive current rectification in chemically-modified nanopores paves a new way for controlling the preferential direction of the ion transport in nanofluidics by modulating the temperature, which has the potential to build novel nanomachines with smart fluidic communication functions for future lab-on-chip devices.

Cysteine and pH-responsive hydrogel based on a saccharide derivative with an aldehyde group.

For the development of chemoresponsive hydrogel, a new saccharide-derived hydrogelator 1 [methyl-4,6-O-(4'-aldehydephenylidene)-alpha-D-glucopyranoside] was synthesized and characterized. The resulting hydrogel not only shows thermal responsiveness but also exhibits cysteine and pH responsiveness due to the presence of aldehyde and acetal groups in 1. The release of guest molecules from the hydrogel of 1 was examined by employing compound 2 (fluorescein disodium) and compound 3 [methyl-4,6-O-(2'-pyrenylidene)-alpha-D-glucopyranoside] as guest molecules. The results indicate that the release of compound 2 from the hydrogel of 1 is controlled by the diffusion process, while the release of compound 3 from the hydrogel of 1 is facilitated by the presence of cysteine. These results demonstrate (1) the proof of principle to design chemoresponsive gels by incorporating reactive groups into the gelators and (2) it is possible to stimulate the release of guest molecules from hydrogels upon addition of reactive chemicals by manipulating the intermolecular interactions among the hydrogelators and guest molecules.

Fluorescent DNA-poly(phenylenevinylene) hybrid hydrogels for monitoring drug release.

A new class of fluorescent DNA-poly(phenylenevinylene) hybrid hydrogels (DNA/SP-PPV) have been prepared by in situ polymerization of monomer with salmon DNA as template, which are used for monitoring drug release driven by media pH.

Fluorescence logic-signal-based multiplex detection of nucleases with the assembly of a cationic conjugated polymer and branched DNA.

An energy-transfer cascade is generated from a cationic conjugated polymer (PFP) and negatively charged, Y-shaped DNA labeled with three dyes at its termini (fluorescein (Fl), Tex Red, and Cy5). Multistep fluorescence resonance energy transfer regulates the fluorescence intensities of PFP and the dyes. Different types of logic gates can be operated by observing the emission wavelengths of different dyes with multiplex nucleases as inputs.

A novel building block for donor-acceptor conjugated polymers containing perylene, poly(p-phenylenevinylene), and fullerene.

A series of new polymers containing perylene, poly(p-phenylenevinylene) (PPV) and/or pendant fullerene units have been synthesized by Wittig condensation. All of the polymers were characterized by 1HNMR, FT-IR, and GPC. The optical properties of the polymers were studied by UV-vis and FL spectra. The cyclic voltammetry showed us a good candidate for a photoinduced electron-transfer system. And the photocurrent measurement revealed an interesting phenomenon that the photocurrent increased with the contents of the fullerene in the polymers increased.

Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials.

Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of <0.1 K and a high-pressure-sensing sensitivity of up to 28.9 kPa(-1). More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

Molecular and nanoscale materials and devices in electronics.

Over the past several years, there have been many significant advances toward the realization of electronic computers integrated on the molecular scale and a much greater understanding of the types of materials that will be useful in molecular devices and their properties. It was demonstrated that individual molecules could serve as incomprehensibly tiny switch and wire one million times smaller than those on conventional silicon microchip. This has resulted very recently in the assembly and demonstration of tiny computer logic circuits built from such molecular scale devices. The purpose of this review is to provide a general introduction to molecular and nanoscale materials and devices in electronics.

Organic thermoelectric materials and devices based on p- and n-type poly(metal 1,1,2,2-ethenetetrathiolate)s.

A series of metal coordination polymers containing 1,1,2,2-ethenetetrathiolate (ett) linking bridge (poly[Ax(M-ett)]) are synthesized. The Seebeck coefficients of these conducting materials are high, and vary according to the center metals and counter cations. The TE device fabricated demonstrates the great potentials of these materials for TE applications.

A convenient preparation of multi-spectral microparticles by bacteria-mediated assemblies of conjugated polymer nanoparticles for cell imaging and barcoding.

A novel technique was developed for preparing encoded multicolour microparticles based on the self-assembly of bacteria and conjugated polymer nanoparticles (CPNs) by a very simple and time-saving manner. These bacteria-CPNs microparticles show multicolor emissions by tuning FRET efficiencies among CPNs under single excitation wavelength and can be successfully applied for cell imaging and optical barcoding.

Architecture of graphdiyne nanoscale films.

We have demonstrated a methodology to generate large area graphdiyne films with 3.61 cm(2) on the surface of copper via a cross-coupling reaction using hexaethynylbenzene. The device based on graphdiyne films for measurement of electrical property is fabricated and shows conductivity of 2.516 x 10(-4) S m(-1) indicating a semiconductor property.

A biomimetic zinc activated ion channel.

A novel biomimetic zinc activated ion channel was prepared by incorporating a zinc responsive peptide, zinc finger, into a single polymeric nanochannel.

Single-nucleotide polymorphism (SNP) genotyping using cationic conjugated polymers in homogeneous solution.

This protocol describes a simple, convenient and sensitive single-nucleotide polymorphism (SNP) genotyping method using an optically amplifying cationic conjugated polymer and single base primer extension reaction. The fluorescence resonance energy transfer (FRET) efficiency between the conjugated polymer (PFP, poly{(1,4-phenylene)-2,7-[9,9-bis(6'-N,N,N-trimethyl ammonium)-hexyl fluorene] dibromide}) and a fluorescein-labeled dNTP (dNTP-Fl) is correlated to the incorporation of the dNTP-Fl into an allele-specific primer; incorporation occurs by a single base extension reaction when the target DNA and the primer are complementary at the SNP site. By triggering the FRET from PFP to fluorescein and measuring the change in fluorescence intensity of samples, the SNP genotypes can be discriminated. In comparison with other SNP genotyping methods, this protocol simplifies procedures and improves sensitivity by eliminating the need for primer labeling, cumbersome workups, chemical/enzymatic coupling reactions and sophisticated instruments. The assay takes about 2 h for PCR amplification followed by 5.5-7.5 h to obtain the genotypes.

Synthesis, characterization, and field-effect transistor properties of carbazolenevinylene oligomers: from linear to cyclic architectures.

Two cyclic carbazolenevinylene dimers 1 and 2 were synthesized by McMurry coupling reactions. A linear compound 3 was also prepared for comparison. Compounds 1-3 were fully characterized by means of NMR spectroscopy, HRMS, elemental analysis, and UV/Vis absorption spectroscopy. Quantum chemical simulations showed that the cyclic compounds possessed smaller HOMO-LUMO gaps and more extended conjugation. The UV/Vis absorption spectra of the cyclic compounds showed blueshifts compared with that of the linear compound 3. Time-dependent DFT (TD-DFT) analysis revealed that this was due to the different selection rules for molecules with cyclic and linear architectures. The cyclic conformation also significantly affected the molecular ordering in the solid state. The X-ray crystal structure of 1 showed partial pi-pi overlapping between the adjacent molecules. Thin films of 1-3 were fabricated by the vacuum-deposition method on Si/SiO(2) substrates. Multicrystalline thin films were obtained from compounds 1 and 2, but only amorphous thin films could be obtained for the linear compound 3. Another important difference between the cyclic and linear compounds was the reduced reorganization energy for the cyclic compounds. These two facts have resulted in improved field-effect transistor (FET) mobilities for the cyclic compounds compared with the linear compound. In addition, as the substrate temperature has a significant influence on the morphology and the degree of crystallinity of the thin films deposited, the device performance could be optimized by varying the substrate temperature. The FET devices based on 2 gave the highest mobility of 0.013 cm(2) V(-1) s(-1). The results showed that carbazole derivatives with cyclic structures might make better FETs.