Conjugated Aromatic Polyimines. 2. Synthesis, Structure, and Properties of New Aromatic Polyazomethines

Yang, Chen-Jen; Jenekhe, Samson A.

doi:10.1021/ma00108a054

Cited by 356 publications

(221 citation statements)

References 17 publications

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“…The optical band-gap calculated from the absorption onset (704 nm) of PPTQX in the film was 1.76 eV, which is slightly larger than that of TQ1 (1.70 eV), 10 but lower than those of LBPP (1.8 eV) and APFO (2.0 eV). 11 The oxidation onset potential of PPTQX was 0.80 V, corresponding to its HOMO level of −5.20 eV, 18 which is higher than those of TQ1 (−5.7 eV), LBPP (~−5.5 eV) and APFO (−5.8 eV). The LUMO energy level of PPTQX, calculated from the optical band gap and HOMO energy level, was −3.47 eV.…”

mentioning

confidence: 95%

Synthesis of a Phenothiazine-Quinoxaline Polymer for Photovoltaic Applications

Jang¹,

Yang²,

Kim³

et al. 2013

Bulletin of the Korean Chemical Society

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Polymer solar cells (PSCs) have attracted considerable attention because of their unique advantages of low cost, light weight, and potential use in flexible devices.1,2 Based on the concept of a bulk heterojunction (BHJ) structure, 3PSCs made by blending poly(3-hexylthiophene) (P3HT) as a p-type material and [6,6]-phenyl-C61-butyric acid methyl ester (PC 61 BM) as an n-type material have been most intensively investigated and have shown power conversion efficiencies (PCEs) up to 5-6%. 4,5PCE of photovoltaic devices is proportional to the shortcircuit current density (J sc ), the open-circuit voltage (V oc ), and the fill factor (FF). The J sc of a solar cell is strongly affected by the absorption of the active layer, and thus an ideal p-type polymer should have a broad and strong absorption spectrum, which requires the polymer to have a low band-gap. The V oc is tightly related to the energy difference between the highest occupied molecular orbital (HOMO) of the p-type polymer and the lowest unoccupied molecular orbital (LUMO) of PCBM. Thus, the p-type polymer should have a low band-gap with appropriate energy levels of HOMO and LUMO. 6A facile method to synthesize low band-gap polymers is to combine electron-rich (electron-donor, D) and electrondeficient (electron-acceptor, A) monomers, forming alternating D-A type polymers.7-9 Quinoxaline was reported to be a good acceptor that can be combined with appropriate donors. For example, a thiophene-bis(3-octyloxyphenyl)-quinoxaline polymer (TQ1) exhibited PCEs up to 6.0%. 10Alternating copolymers consisting of bis(3-alkoxyphenyl)-quinoxaline and either dialkoxybenzene (LBPP) or fluorine (APFO) with a thiophene spacer showed PCEs up to 2.9% 11Another alternating copolymers of quinoxaline and either thieno[3,2-b]thiophene or carbazole with a thiophene spacer showed PCEs of 2.27% and 1.8%, respectively.12,13 A copolymer of 2,3-diphenylquinoxaline-based combined with a ladder type oligo-p-phenylene with a thiophene spacer showed a PCE of 3.04%.14 Some other types of quinoxaline-based copolymers with much lower PCEs were also reported. 15,16Poly(10-hexyl-10H-hexylphenothiazine-3,7-diyl) is a very strong electron donor and has a high ionization potential and has thus been used as a hole injection material in polymer light-emitting diodes. 17D-A type polymers consisting of phenothiazine and quinoxaline are also expected to be p-type materials with low band-gaps, but such polymers have not yet been reported in the literature. Thus, we attempted to synthesize a copolymer (PPTQX) consisting of alternating phenothiazine (PT) and dithienylquinoxaline (QX) segments for photovoltaic applications.As shown in Scheme 1, diboronic ester (compound 1) was reacted with dibromide (compound 2) in the presence of a palladium catalyst via Suzuki coupling to give the corresponding polymer, PPTQX. The polymer was purified using a Soxhlet extraction. The 1 H NMR of the isolated polymer is shown in Figure 1, where the two different sets of aromatic protons (a, b) and four aliphatic protons (d) ...

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confidence: 95%

Synthesis of a Phenothiazine-Quinoxaline Polymer for Photovoltaic Applications

Jang¹,

Yang²,

Kim³

et al. 2013

Bulletin of the Korean Chemical Society

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“…The values of the ionization potential (IP) and EA can also be estimated from these onset potentials (versus SCE) using equations (1) (2). [41][42][43][44][45] IP ¼E first oxidation +4:39 eV ð1Þ…”

Section: Resultsmentioning

confidence: 99%

Synthesis and memory performance of a conjugated polymer with an integrated fluorene, carbazole and oxadiazole backbone

Zeng

Liu

Zhang

et al. 2011

Polym J

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A new soluble conjugated polymer, poly[{9-(4-methoxyphenyl)-9H-carbazole}(9,9-dioctylfluorene)(2,5-diphenyl-1,3,4-oxadiazole)] (PCFO), was synthesized through the Suzuki coupling reaction. The absolute fluorescence quantum yield of PCFO was measured using the integrating sphere of a photoluminescence spectrofluorometer, and changed from 49.1% for a dilute tetrahydrofuran solution to 16.2% for a thin film due to the existence of a strong fluorescence quenching effect in the solid state. The HOMO-LUMO bandgap (3.07 eV) calculated from the electrochemical measurement is nearly identical to the optical bandgap (3.06 eV) estimated from the ultraviolet/visible absorption onset data. This film was attached to aluminum and indium-tin oxide contacts to fabricate a memory device with typical bistable electrical switching, nonvolatile write-once read-many-times memory performance, a turn-on voltage of BÀ2.3 V and an ON/OFF ratio of B10 5 . Degradation of the current density was observed for neither the ON nor OFF states after one hundred million continuous read cycles, which indicates that both states were insensitive to read cycles. Keywords: donor-acceptor system; molecular devices; polymer memory; synthesis INTRODUCTIONPolymer memories are proposed to revolutionize electrical applications by providing extremely inexpensive, lightweight and transparent modules that can be fabricated onto plastic, glass or the top layer of CMOS hybrid integration circuits, 1,2 and have been identified as an emerging memory technology by the International Technology Roadmap for Semiconductors since year 2005. 3 Rather than encoding '0'and '1' as a charge stored in the cell of a silicon device, polymer memory stores data in an entirely different form, such as in a highand low-conductivity response to an applied voltage. 4 The molecular structure of polymers can be tailored by functionalizing them with electron donors (D) and acceptors (A) of different strengths, spacer moieties of different steric effects for the electroactive pendant groups, or nanostructured electroactive materials, to induce different memory behaviors in simple metal/polymer/metal devices. 5,6 Very recently, Liu and Chen 7 highlighted the recent developments in D-A polymers for resistive switching memory device applications including conjugated polymers, functional polyimides, nonconjugated pendent polymers and polymer composites. D/A polymer materials (usually carbazole or

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“…To understand the electronic structure of conjugated polymers it is essential to establish the relative positions of the characteristic electronic energy levels such as the highest occupied molecular orbital (HOMO or п level), the lowest unoccupied molecular orbital (LUMO or п), and the associated energy parameters [25,26]. The oxidation peaks in cyclic voltammograms probably correspond to the oxidation of hydroxyl groups to form phenoxy radicals.…”

Section: Electrochemical and Conductivity Propertiesmentioning

confidence: 99%

Synthesis, characterization and electrochemical properties of poly(phenoxy-imine)s containing carbazole unit

2017

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Several new Schiff base polymers were synthesized via oxidative polymerization method in an aqueous alkaline medium in the presence of NaOCl as an oxidant and were confirmed by FT-IR, 1 H-NMR, 13 C-NMR and UV-Vis spectroscopic techniques. Furthermore, cyclic voltammetry measurements were carried out and the HOMO-LUMO energy levels and electrochemical band gaps (E g ′) were calculated. Additionally, the optical band gaps (E g ) were determined using their UV-Vis spectra of the materials. The morphologic properties of the polymers were investigated by scanning electron microscopy. In addition, the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index values of the polymers were determined by gel permeation chromatography technique. Electrical conductivity measurements of the doped (with iodine) and undoped polymer related to doping time were carried out by four-point probe technique using a Keithley 2400 electrometer. Their thermal behaviors were determined by TG-DTA and DSC measurements. The synthesized compounds were soluble in common solvents such as DMF, THF and DMSO. Photoluminescence properties of the polymers were determined in different concentrations of DMF solvent.

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Conjugated Aromatic Polyimines. 2. Synthesis, Structure, and Properties of New Aromatic Polyazomethines

Cited by 356 publications

References 17 publications

Synthesis of a Phenothiazine-Quinoxaline Polymer for Photovoltaic Applications

Synthesis of a Phenothiazine-Quinoxaline Polymer for Photovoltaic Applications

Synthesis and memory performance of a conjugated polymer with an integrated fluorene, carbazole and oxadiazole backbone

Synthesis, characterization and electrochemical properties of poly(phenoxy-imine)s containing carbazole unit

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