We demonstrate a strategy for designing high-performance, ambipolar, acene-based field-effect transistor (FET) materials, which is based on the replacement of C-H moieties by nitrogen atoms in oligoacenes. By using this strategy, two organic semiconductors, 6,13-bis(triisopropylsilylethynyl)anthradipyridine (1) and 8,9,10,11-tetrafluoro-6,13-bis(triisopropylsilylethynyl)-1-azapentacene (3), were synthesized and their FET characteristics studied. Both materials exhibit high and balanced hole and electron mobilities, 1 having μ(h) and μ(e) of 0.11 and 0.15 cm(2)/V·s and 3 having μ(h) and μ(e) of 0.08 and 0.09 cm(2)/V·s, respectively. The successful demonstration of high and balanced ambipolar FET properties from nitrogen-containing oligoacenes opens up new opportunities for designing high-performance ambipolar organic semiconductors. 相似文献
Photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes. Single component semiconducting photoresist exhibits both semiconducting and photo-patterning properties, and as a result, the device fabrication process can be simplified. However, the design of semiconducting polymeric photoresist with ambipolar semiconducting property remains challenging. In this paper, we report a single component semiconducting photoresist (PFDPPF4T-N3) by incorporating azide groups and noncovalent conformation locks into the side alkyl chains and conjugated backbones of a diketopyrrolopyrrole-based conjugated polymer, respectively. The results reveal that PFDPP4FT-N3 exhibits ambipolar semiconducting property with hole and electron mobilities up to 1.12 and 1.17 cm2 V?1 s?1, respectively. Moreover, field effect transistors with the individual photo-patterned thin films of PFDPPF4T-N3 also show ambipolar semiconducting behavior with hole and electron mobilities up to 0.66 and 0.80 cm2 V?1 s?1, respectively. These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists, which hold great potential for flexible electronics processed by all photolithography.
A series of peptides with an alternating sequence of alkoxyamine conjugated lysine and glycine residues were synthesized by classical solution phase peptide coupling. The resulting peptides containing up to eight alkoxyamine moieties were used as initiators in nitroxide-mediated polymerization (NMP) to obtain peptide-polymer conjugates with well defined linear peptide backbones and a defined number of polymeric side chains. Polymerization of styrene and N-isopropylacrylamide (NIPAM) occurred in a highly controlled fashion. Molecular weight and polydispersity index (PDI) were determined by gel permeation chromatography (GPC). Aggregation behaviour of these hybrid materials was investigated by dynamic light scattering (DLS) and atomic force microscopy (AFM). Depending on composition, number and length of the polymer side chains, the conjugates aggregate to different topologies. Whereas peptide-polystyrene conjugates may aggregate to so called honeycomb structures, peptide-poly-N-isopropylacrylamide conjugates show differentiated aggregation behaviour. 相似文献
The synthesis of cationic cyclopentadienyliron-containing polymers with pendent azobenzene chromophores was accomplished via metal-mediated nucleophilic aromatic substitution reactions. All of the desired polymers were isolated as vibrantly coloured materials and displayed excellent solubility in polar aprotic solvents. Cationic and neutral cyclopentadienyliron polymers incorporating azo dyes in the backbone were also prepared. Reactions of azo dyes with dichlorobenzene complexes allowed for the isolation of cationic cyclopentdienyliron (CpFe+) complexes with azo dye chromophores. These complexes were then reacted with 1,1′-ferrocenedicarbonyl chloride to produce the trimetallic monomers with terminal chloro groups. These monomers contained two pendent CpFe+ cations and a neutral iron moiety in the backbone. Nucleophilic substitution reactions of these monomers with oxygen and sulfur containing dinucleophiles gave rise to a new class of polymeric materials. The pendent CpFe+ moieties could also be cleaved from the polymer backbones using photolysis to afford novel ferrocene based polymers. The UV-vis spectra of the organoiron monomers and polymers display similar wavelength maxima however incorporating azobenzene chromophores with electron-withdrawing substituent into the polymer chains resulted in bathochromic shifts of the λmax values. 相似文献
In this article, three novel and simple molecular structure with donor-acceptor (D-A) type copolymers via only head-to-head alkoxy (OR) and/or alkylthio (SR) side chains onto the bithiophene (BT) as donor units and fluorinated benzotriazole (FBTA) as acceptor unit, namely, PBTOR-FBTA, PBTOSR-FBTA and PBTSR-FBTA, were successfully designed and synthesized. The impacts of sulfur-oxygen (S⋯O) or sulfur-sulfur (S⋯S) noncovalent interactions on their physicochemical properties, molecular stacking, carrier mobility, morphologies of blend films, as well as their photovoltaic performance were deeply and systematically studied. The introduction of SR side-chains suddenly lowered the highest occupied molecular orbital (HOMO) energy levels, blue-shifted absorption, enhanced π-π stacking, as well as improved morphology of the photoactive layer blends in comparison with the reference polymer without SR side-chain. Polymer solar cells (PSCs) were fabricated to estimate their photovoltaic performance of the polymers. Under an optimized blend ratio of PBTSR-FBTA:PC71BM (1:0.8, w/w), the PBTSR-FBTA-based device exhibits a higher power conversion efficiency (PCE) of 6.25%, which is about 3.34 and 1.87 folds than that of the PBTOR-FBTA and PBTOSR-FBTA-based devices, respectively. Our research results demonstrate that the modification of the simple and low-cost SR side chains is an effective strategy to improve the photovoltaic performance of the polymers. 相似文献
A series of molecular brushes with a polyfluorene (PF) backbone and polymethacrylic acid side chains of varying lengths were prepared by atom transfer radical polymerization. The structure and composition of the synthesized compounds were confirmed by 1H NMR and IR spectroscopy. Effect of the length of the backbone on spectral and conformational parameters of the macromolecules in solutions was analyzed. The grafting density of side chains was about 90%. Spectral methods have been used to determine the dependence of side chain grafting on the luminescent properties of polymer solutions, including quantum yields. It was shown that an optimal length of polymethacrylic acid side chains provides solubility of the polymer brushes. Solutions of PF-graft-polymethacrylic acid complexes with the model substance curcumin were investigated. It was established that the molecular brushes containing curcumin form monomolecular micelles. Molecular brushes with zinc phthalocyanine, potential systems for photodynamic, and photothermal therapy, were studied. 相似文献
We chose a series of isoindigo-based conjugated polymer(ⅡDDT,ⅡDDT-C3 and ⅡDDT-C4) with different length of side chains and bifurcation positions to investigate the relationship between the degree of alignment and the length of side chains and bifurcation positions.We found that the dichroic ratio was increased from 2.37 to 5.23 when the side chain was longer and the bifurcation position was away from the backbone.The π-π stacking distance was decreased from 3.67 A to 3.61 A when the bifurcation position was away from the backbone because of its smaller hindrance and the d-spacing of the(100)was increased from 20.06 A to 25.21 A when the side chain was longer.All the polymers were adopted an edge-on orientation with the backbone paralleled with the long axis of fibers.The weak interaction of side-chain in ⅡDDT-C4 was beneficial for the molecules being rearranged in parallel during the contact line receding and the strong n-n interaction could accelerate the interchain assembly of the parallel molecules through π-π interaction to form aligned fibers. 相似文献
In this paper, we present a new design strategy for healable polymeric semiconductors, which are demanding for the future flexible electronics, by incorporating coumarin groups in the polymer side chains. The selection of coumarin groups is based on the fact that photo-dimerization can occur to coumarins upon UV light irradiation, thus side chains of conjugated polymers with coumarins can be cross-linked. The photo-crosslinking of side chains has negligible effect on the thin film morphology and interchain packing order for the DPP-based conjugated polymer PDPP4T-DCM with coumarins in the side chains. However, the photo-crosslinking can facilitate the repair of the mechanically damaged thin film of PDPP4T-DCM and the recovery of the semiconducting properties. Additionally, the photo-crosslinking due to the coumarins in the side chains can lock thin film morphology and thus improve the thermal stability of charge transport. 相似文献
To examine the quenching of a triplet exciton by low triplet energy (E(T)) polymer hosts with different chain configurations for high E(T) phosphor guests, the quenching rate constant measurements were carried out and analyzed by the standard Stern-Volmer equation. We found that an effective shielding of triplet energy transfer from a high E(T) phosphor guest to a low E(T) polymer host is possible upon introducing dense side chains to the polymer to block direct contact from the guest such that the possibility of Dexter energy transfer between them is reduced to a minimum. Together with energy level matching to allow charge trapping on the guest, high device efficiency can be achieved. The extent of shielding for the systems of phenylene-based conjugated structures from iridium complexes follows the sequence di-substituted (octoxyl chain) in the para position (dC8OPPP) is greater than monosubstituted (mC8OPPP) and the PPPs with longer side chains are much higher than a phenylene tetramer (P4) with two short methyl groups. Further, capping the dialkoxyl-susbstituents with a carbazole (Cz) moiety (CzPPP) provides enhanced extent of shielding. Excellent device efficiency of 30 cd/A (8.25%) for a green electrophosphorescent device can be achieved with CzPPP as a host, which is higher than that of dC8OPPP as host (15 cd/A). The efficiency is higher than those of high E(T) conjugated polymers, poly(3,6-carbazole) derivatives, as hosts (23 cd/A). This observation suggests a new route for molecular design of electroluminescent polymers as a host for a phosphorescent dopant. 相似文献
A new network polymer electrolyte matrix with polyether in the side chains and main chains was synthesized by the azo-macroinitiator method and urethane reaction. The macroinitiator, polymer and network polymer were confirmed by Fourier-transform infrared (FT-IR) spectroscopy and 1H NMR. FT-IR was also used to study the environment of lithium ions doped in these network polymer electrolytes. Three important groups are considered: N-H, carbonyl, and ether groups. The thermal properties of the polymer electrolytes were measured by differential scanning calorimetry and thermogravimetric analysis. The Tg value of this polymer is less than that of a general comb-like polymer. Added lithium ions interact with the oxygen atoms on ether groups, causing the Tg of the polymer electrolyte to increase. Moreover, the interaction between lithium ions and ether groups decreases the decomposition temperature of the polymer. The conductivity measured by AC impedance reached a maximum of 10−4 S cm−1. A plot of conductivity vs. temperature fit the Vogel-Tamman-Fulcher equation, indicating that ionic mobility in this network polymer electrolyte is coupled to segmental chain movements. 相似文献
Using the spin Hamiltonian method, we have studied the dynamic instability of quasi-one-dimensional spin chains, which are models of the corresponding conjugated polymers. We have considered the example of chain deformation leading to a singular response of the original one-dimensional problem. We have formulated the conditions for activationless character of excitations having multiplicity of the ground state.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 395–401, July–August, 1987.The author expresses thanks to A. A. Ovchinnikov for discussion of the results of the work. 相似文献
In this communication we report the electrical characteristics of hexathiapentacene (HTP) and emphasize the unusual chemical structure and molecular packing. We report field-effect mobilities as high as 0.04 cm2 V-1 s-1 and current on/off ratios of >105. With crystallographic evidence of unusually long S-S bonds compared to normal S-S bonds, we have suggested a unique resonance structure similar to trithiapentalene, which well explains the bonding characteristics of HTP. This work appears to be the first to determine its molecular structure/packing mode and to study its application in organic transistors. 相似文献
Three acceptor-donor-acceptor(A-D-A) conjugated oligomers, i.e., O1, O2 and O3, have been synthesized using diketopyrrolopyrrole(DPP) as an electron-acceptor unit, and naphtho[1,2-b:5,6-b']dithiophene(NDT), anthra[1,2-b:5,6-b']dithiophene(ADT) or dithieno[3,2-b:3',2'-b']naphtho[1,2-b:5,6-b']dithiophene(DTNDT) as electron-donor unit. These oligomers exhibit identical highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) energy levels, which were ca.-5.1 and-3.3 eV, respectively. Upon thermal annealing, all three oligomers formed thin films with ordered microstructures, and their organic thin film transistors(OTFTs) exhibited p-type transport behavior. The mobility was increased with an extension of the size of D-units. O3 showed the best OTFT performance with the mobility of up to 0.20 cm~2·V~(-1)·s~(-1). The film quality of O3 was improved by adding 1 wt% poly(methylmethacrylate)(PMMA). In consequence, the mobility of the O3-based devices was further enhanced to 0.30 cm~2·V~(-1)·s~(-1). 相似文献