Synthesis and properties of blue light‐emitting,silicon‐containing,regio‐ and stereoregular conjugated polymers

This article concerns the hydrosilylation polyaddition of 1,4‐bis(dimethylsilyl)benzene ( 1 ) with 4,4′‐diethynylbiphenyl, 2,7‐diethynylfluorene ( 2b ), and 2,6‐diethynylnaphthalene with RhI(PPh₃)₃ catalyst. Trans‐rich polymers with weight‐average molecular weights (M_w's) ranging from 19,000 to 25,000 were obtained by polyaddition in o‐Cl₂C₆H₄ at 150–180 °C, whereas cis‐rich polymers with M_w's from 4300 to 34,000 were obtained in toluene at 0 °C–r.t. These polymers emitted blue light in 4–81% quantum yields. The cis polymers isomerized into trans polymers upon UV irradiation, whereas the trans polymers did not. The device having a layer of polymer trans‐ 3b obtained from 1 and 2b demonstrated electroluminescence without any dopant. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2774–2783, 2004     

Synthesis and characterization of highly stable blue‐light‐emitting hyperbranched conjugated polymers

Polyfluorene homopolymer ( P1 ) and its carbazole derivatives ( P2 – P4 ) have been prepared with good yield by Suzuki coupling polymerization. P2 is an alternating copolymer based on fluorene and carbazole; P3 is a hyperbranched polymer with carbazole derivative as the core and polyfluorene as the long arms; P4 is a hyperbranched polymer with carbazole derivative as the core and the alternating fluorene and carbazole as the long arms. These polymers show highly thermal stability, and their structures and physical properties are studied using gel permeation chromatography, ¹H NMR, ¹³C NMR, elemental analysis, Fourier transform infrared spectroscopy, thermogravimetry, UV–vis absorption, photoluminescence, and cyclic voltammetry (CV). The influence of the incorporation of carbazole and the hyperbranched structures on the thermal, electrochemical, and electroluminescent properties has been investigated. Both carbazole addition and the hyperbranched structure increase the thermal and photoluminescent stability. The CV shows an increase of the HOMO energy levels for the derivatives, compared with polyfluorene homopolymer ( P1 ). The EL devices fabricated by these polymers exhibit pure blue‐light‐emitting with negligible low‐energy emission bands, indicating that the hyperbranched structure has a strong effect on the PLED characteristics. The results imply that incorporating carbazole into polyfluorene to form a hyperbranched structure is an efficient way to obtain highly stable blue‐light‐emitting conjugated polymers, and it is possible to adjust the property of light‐emitting polymers by the amount of carbazole derivative incorporated into the polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 790–802, 2008     

Synthesis and optical properties of light‐emitting π‐conjugated polymers containing biphenyl and dithienosilole

Copolymers containing oligo(phenylene vinylene) (2.5), fluorene, and 4,4‐dihexyldithienosilole (DTS) units were synthesized and characterized. The π‐conjugated monomers were joined with the palladium(0)‐catalyzed Suzuki–Miyaura coupling reaction, thus forming either biphenyl– or phenyl–thiophene linkages. These polymers were photoluminescent, with the fluorescent quantum efficiency between 54 and 63% and with λ_max for fluorescence at ～448 nm in tetrahydrofuran. The presence of 5% DTS in the copolymers had little influence on the optical absorption and emission wavelengths. Double‐layer light‐emitting‐diode devices using these polymers as emissive layers had low turn‐on voltages (3.5–4 V) and moderate external quantum efficiencies (0.14–0.30%). The results show that DTS plays a positive role in improving the charge‐injection characteristics of poly(phenylene vinylene) materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2048–2058     

Fluorene‐ and benzimidazole‐based blue light‐emitting copolymers: Synthesis,photophysical properties,and PLED applications

Blue light‐emitting materials are receiving considerable academic and industrial interest due to their potential applications in optoelectronic devices. In this study, blue light‐emitting copolymers based on 9,9′ ‐ dioctylfluorene and 2,2′‐(1,4‐phenylene)‐bis(benzimidazole) moieties were synthesized through palladium‐catalyzed Suzuki coupling reaction. While the copolymer consisting of unsubstituted benzimidazoles (PFBI0) is insoluble in common organic solvents, its counterpart with N‐octyl substituted benzimidazoles (PFBI8) enjoys good solubility in toluene, tetrahydrofuran, dichloromethane (DCM), and chloroform. The PFBI8 copolymer shows good thermal stability, whose glass transition temperature and onset decomposition temperature are 103 and 428 °C, respectively. Its solutions emit blue light efficiently, with the quantum yield up to 99% in chloroform. The electroluminescence (EL) device of PFBI8 with the configuration of indium‐tin oxide/poly(ethylenedioxythiophene):poly(styrene sulfonic acid)/PFBI8/1,3,5‐tris(1‐phenyl‐1H‐benzimidazole‐2‐yl)benzene/LiF/Al emits blue light with the maximum at 448 nm. Such unoptimized polymer light‐emitting diode (PLED) exhibits a maximum luminance of 1534 cd/m² with the current efficiency and power efficiency of 0.67 cd/A and 0.20 lm/W, respectively. The efficient blue emission and good EL performance make PFBI8 promising for optoelectronic applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of fluorene‐based hyperbranched polymers for solution‐processable blue,green, red,and white light‐emitting devices

For the purpose of making hyperbranched polymer (Hb‐Ps)‐based red, green, blue, and white polymer light‐emitting diodes (PLEDs), three Hb‐Ps Hb‐ terfluorene ( Hb‐TF ), Hb ‐4,7‐bis(9,9′‐dioctylfluoren‐2‐yl)‐2,1,3‐benzothiodiazole ( Hb‐BFBT ), and Hb‐ 4,7‐bis[(9,9′‐dioctylfluoren‐2‐yl)‐thien‐2‐yl]‐2,1,3‐benzothiodiazole ( Hb‐BFTBT ) were synthesized via [2+2+2] polycyclotrimerization of the corresponding diacetylene‐functionalized monomers. All the synthesized polymers showed excellent thermal stability with degradation temperature higher than 355 °C and glass transition temperatures higher than 50 °C. Photoluminance (PL) and electroluminance (EL) spectra of the polymers indicate that Hb‐TF , Hb‐BFBT , and Hb‐BFTBT are blue‐green, green, and red emitting materials. Maximum brightness of the double‐layer devices of Hb‐TF , Hb‐BFBT , and Hb‐BFTBT with the device configuration of indium tin oxide/poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate)/light‐emitting polymer/CsF/Al are 48, 42, and 29 cd/m²; the maximum luminance efficiency of the devices are 0.01, 0.02, and 0.01 cd/A. By using host–guest doped system, saturated red electrophosphorescent devices with a maximum luminance efficiency of 1.61 cd/A were obtained when Hb‐TF was used as a host material doped with Os(fptz)₂(PPh₂Me₂)₂ as a guest material. A maximum luminance efficiency of 3.39 cd/A of a red polymer light‐emitting device was also reached when Hb‐BFTBT was used as the guest in the PFO (Poly(9,9‐dioctylfluorene)) host layer. In addition, a series of efficient white devices were, which show low turn‐on voltage (3.5 V) with highest luminance efficiency of 4.98 cd/A, maximum brightness of 1185 cd/m², and the Commission Internationale de l'Eclairage (CIE) coordinates close to ideal white emission (0.33, 0.33), were prepared by using BFBT as auxiliary dopant. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

High‐efficiency blue light‐emitting polymers based on 3,6‐silafluorene and 2,7‐silafluorene

A novel blue‐emitting polymer based on 3,6‐silafluorene and 2,7‐silafluorene was synthesized via the Suzuki polycondensation. The resulting polymers are readily soluble in common organic solvents, such as toluene, xylene, THF, and chloroform. The thermal, electrochemical, photophysical, and electroluminescence properties of the resulting polymers were investigated. The device fabricated from the copolymer with a configuration of ITO/PEDOT:PSS/PVK/polymer/Ba/Al exhibited an external quantum efficiency of 1.95%, a luminous efficiency of 1.69 cd A^?1 and a maximal brightness of 6000 cd m^?2. It has been found that the incorporation of the 3,6‐silafluorene unit into the poly(2,7‐silafluorene) main chain can not only improve the color purity of the devices from the resulting copolymer but also enhance its device efficiency. Moreover, no undesired long‐wavelength green emission was observed in the PL spectra of P36‐27SiF90 compared to that of PFO with a dominating emission at 500–600 nm after thermal annealing at 200 °C for 8 h. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4941–4949, 2007     

Synthesis and properties of through‐space conjugated polymers based on cyano‐substituted poly(p‐arylenevinylene)s

New through‐space cyano‐substituted poly(p‐arylenevinylene)s containing a [2.2]paracyclophane unit were synthesized by the Knoevenagel reaction. Polymers 5 and 7 have cyano groups at α‐positions and β‐positions from the dialkoxyphenylene unit, respectively. Their optical and electrochemical behaviors were investigated in detail in comparison with their model compounds. Polymers 5 and 7 exhibited through‐space conjugation via the cyclophane units. Polymer 5 showed greenish blue emission (λ_max = 477 nm) in diluted solution with fluorescence quantum efficiency (?_F) of only 0.007, whereas polymer 7 emitted in the bluish green region (λ_max = 510 nm) with ?_F of 0.32. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5979–5988, 2009     

Synthesis and electroluminescent properties of a phenothiazine‐based polymer for nondoped polymer light‐emitting diodes with a stable orange‐red emission

A novel phenothiazine‐based polymer was synthesized through the Heck reaction of 3,7‐divinyl‐N‐octyl‐phenothiazine with 4,7‐dibromo‐2‐octylbenzotriazole according to the alternating donor–acceptor strategy. The polymer was characterized with ¹H NMR, infrared spectroscopy, gel permeation chromatography, cyclic voltammetry, ultraviolet–visible spectroscopy, and fluorescence spectroscopy. With the polymer used as an active layer, three nondoped polymer light‐emitting diodes (PLEDs) with a double‐layer configuration were fabricated by the spin‐coating approach with different thermal annealing processes. The emission maximum in electroluminescent spectra was stabilized at 616 nm. The maximum luminance reached 2432 cd/m². The coordinate value of Commission International de l'Eclairage 1931 in the double‐layer PLEDs after the thermal treatment was nearly stabilized at (x, y) =(0.62, 0.38). Additionally, the luminous efficiency of device II reached a balanceable state with an increase in the current. Therefore, the polymer had an orange‐red emission with stable chromaticity coordinates under different driving voltages. Finally, a nondoped device with a stable luminous efficiency and chromaticity was obtained. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4867–4878, 2007     

Synthesis and properties of new fluorene‐based polyquinoxalines with an ether linkage in the main chain for light‐emitting diodes

A new series of fluorene‐based polyquinoxalines with an ether linkage in the main chain were prepared by the polycondensation reaction between a tetraketone monomer and 3,3′,4,4′‐tetraaminodiphenyl ether. The polycondensation was usually carried out in m‐cresol. The resulting polymers ( P1 – P3 ) [ P1 = poly(quinoxaline‐co‐9,9‐dihexyl‐2,7‐dimethyl‐9H‐fluorene) P2 = poly(quioxaline‐co‐9,9‐dihexyl‐9‐pentyl‐2,7‐di‐p‐tolyl‐9H‐fluorene) P3 = poly(quioxaline‐co‐9,9‐bis‐(4‐methoxy‐phenyl)‐2,7‐dimethyl‐9H‐fluorene)] showed good solubility in common organic solvents and high thermal stability with only a 5% weight loss up to 440 °C. P1 and P2 had very high glass‐transition temperatures of 212 and 223 °C, respectively, whereas P3 did not show any phase‐transition temperature in repeated scans up to 300 °C. All the polymers in photoluminescence showed blue emissions in the range of 432–465 nm, both in chloroform solutions and in thin films. Light‐emitting diode devices of the configuration indium tin oxide/poly(3,4‐ethylenedioxythiophene)/polymer:poly(N‐vinylcarbazole) blend (2:8)/LiF/Al were fabricated with P1 or P2 and emitted blue light with electroluminescence peak wavelengths of 434 and 448 nm, respectively. The maximum brightness and the external quantum efficiency of P1 were 0.56 μW/cm² at 29 V and 0.056%, whereas P2 showed 0.50 μW/cm² at 34 V and a relatively low value of 0.015%, respectively. Cyclic voltammetry studies revealed that these polymers possessed low‐lying ionization potential energy levels ranging from ?5.49 to ?5.86 eV and low‐lying electron affinity energy levels ranging from ?2.65 to ?2.88 eV. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1189–1198, 2006     

Synthesis and characterization of new selenophene‐based conjugated polymers for organic photovoltaic cells

Three new polymers poly(3,4′′′‐didodecyl) hexaselenophene) (P6S), poly(5,5′‐bis(4,4′‐didodecyl‐2,2′‐biselenophene‐5‐yl)‐2,2′‐biselenophene) (HHP6S), and poly(5,5′‐bis(3′,4‐didodecyl‐2,2′‐biselenophene‐5‐yl)‐2,2′‐biselenophene) (TTP6S) that have the same selenophene‐based polymer backbone but different side chain patterns were designed and synthesized. The weight‐averaged molecular weights (M_w) of P6S, HHP6S, and TTP6S were found to be 19,100, 24,100, and 19,700 with polydispersity indices of 2.77, 1.48, and 1.41, respectively. The UV–visible absorption maxima of P6S, HHP6S, and TTP6S are at 524, 489, and 513 nm, respectively, in solution and at 569, 517, and 606 nm, respectively, in the film state. The polymers P6S, HHP6S, and TTP6S exhibit low band gaps of 1.74, 1.95, and 1.58 eV, respectively. The field‐effect mobilities of P6S, HHP6S, and TTP6S were measured to be 1.3 × 10^?4, 3.9 × 10^?6, and 3.2 × 10^?4 cm² V^?1 s^?1, respectively. A photovoltaic device with a TTP6S/[6,6]‐phenyl C₇₁‐butyric acid methyl ester (1:3, w/w) blend film active layer was found to exhibit an open circuit voltage (V_OC) of 0.71 V, a short circuit current (J_SC) of 5.72 mA cm^?2, a fill factor of 0.41, and a power conversion efficiency (PCE) of 1.67% under AM 1.5 G (100 mW cm^?2) illumination. TTP6S has the most planar backbone of the tested polymers, which results in strong π–π interchain interactions and strong aggregation, leading to broad absorption, high mobility, a low band gap, and the highest PCE. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Hyperbranched framework of interrupted π‐conjugated polymers end‐capped with high carrier‐mobility moieties for stable light‐emitting materials with low driving voltage

A novel series of soluble hyperbranched interrupted π‐conjugated polymers (HICPs) based on complicated 9,9‐diarylfluorenes (CDAFs) branching core and end‐capped with high carrier‐mobility pyrene moieties were synthesized via the “A₂ + A′₂ + B₃” type Suzuki coupling condensation. The new polymer architecture improves the spectrum stability than the corresponding linear and hyperbranched polymers in PLEDs. Besides, it overcomes the drawback of high driving voltage of common interrupted π‐conjugated polymers. CDAF1 exhibits excellent thermal and morphological stability with a decomposition temperature (T_d) higher than 445 °C and a glass transition temperature (T_g) up to 128 °C. No obvious low‐energy green emission band at 520 nm was observed under extreme thermal annealing conditions in air at 200 °C for 12 h. The CDAF1 device shows stable blue emission with the peak at 422 and 447 nm. The Commission International d'Eclairage (CIE) 1931 coordinates is (0.18, 0.16) and the brightness reaches 1051 cd/m² at 15.7 V. White PLED based on CDAF1/MEH‐PPV blends exhibits a low turn‐on voltage of 4.8 V with voltage‐independent CIE of (0.32, 0.32). Molecular simulations were used to investigate the conformation and interchain interaction. HICPs based on CDAFs tethered with high‐mobility moieties are promising stable blue and host materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6451–6462, 2009     

Functional,hyperbranched polyesters via baylis–hillman polymerization

Hyperbranched polyesters are among the most common hyperbranched polymers. One of the interesting features of hyperbranched polyesters is that they contain unreacted hydroxyl and carboxylic acid groups at the linear and terminal structural units, which can be postmodified to adjust thermal, solubility, or mechanical properties, or to prepare core–shell type architectures. This article reports on the synthesis of a novel class of hyperbranched polyesters via an A₂ + B₃ type Baylis–Hillman polymerization of 2,6‐pyridinedicarboxaldehyde and trimethylolpropane triacrylate. Baylis–Hillman polymerization generates highly functional polyesters that contain not only unreacted aldehyde and/or acrylate groups at the linear and terminal structural units but also chemically orthogonal vinyl and hydroxyl groups along the polymer backbone. Using 3‐hydroxyquinuclidine as the catalyst, hyperbranched polymers with number‐average molecular weights up to 7500 g/mol and degrees of branching up to 0.81 were obtained. To demonstrate the versatility of these hyperbranched polyesters to act as platforms for further derivatization, the orthogonal postpolymerization modification of the hydroxyl, vinyl, and pyridine functional moieties with phenyl isocyanate, methyl‐3‐mercaptopropionate, and methyl iodide is presented. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.     

Synthesis,optical and electrochemical properties of arylenevinylene‐based π‐conjugated polymers with imidazolium units in the main chain

Arylenevinylene‐based π‐conjugated polymers containing imidazolium cationic units in the main chain and their model compounds were synthesized and characterized in terms of optical and electrochemical properties. 9,9‐Bisoctylfluorene, 2,5‐bisdodecyloxybenzene, and 3‐dodecylthiophene were introduced as arylene units with different donor characteristics to evaluate the effect on the highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) gap energy. The UV–vis and fluorescence spectra of cationic polymers and model compounds with iodide counter anion exhibited a significant blue shift with respect to the parent neutral molecules. X‐ray single crystal analysis for model compounds revealed that the effective π‐conjugation length of cationic model compounds decreased compared to the neutral model compounds by means of twisted conformation directed by CH‐π interactions between N‐methyl groups of imidazolium and neighboring aryl units. The cyclic voltammetry measurement suggested the negative shift of LUMO levels by the conversion of imidazole to imidazolium, indicating the electron‐accepting characteristics of cationic imidazolium unit. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Facile synthesis of ortho‐Phenylene‐based conjugated polymers through transformation of cross‐conjugated poly(2,3‐diaryl[2]dendralene)s and their optical properties

We studied the facile synthesis of ortho‐phenylene‐based conjugated polymers through transformation of cross‐conjugated polymers having [2]dendralene moiety, poly(2,3‐diaryl[2]dendralene)s ( P1 s), and demonstrated the sequential synthesis of (Z)‐alkene‐ and ortho‐arylene‐containing conjugated polymers from P1 s. P1 s were transformed into cyclohexa‐1,4‐diene‐containing conjugated polymers ( P2 s) through a Diels–Alder reaction. Aromatization of the cyclohexa‐1,4‐diene skeleton was achieved by using 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone to give the ortho‐phenylene‐containing conjugated polymers ( P3 s). The ultraviolet–visible and fluorescence spectra of the cross‐conjugated polymers P1 s, and the conjugated polymers P2 s and P3 s indicated that the π–π interactions between the arylene moieties in P2 s were stronger than those in P1 s and P3 s. The synthetic method for P2 s and P3 s offers an effective synthesis of various types of (Z)‐alkene‐ and ortho‐arylene‐containing conjugated polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 827–832     

Synthesis and optical and electrochemical properties of new π‐conjugated 1,3,5‐triazine‐containing polymers

Two new π‐conjugated polymers containing 1,3,5‐triazine units in the main chain, Pa and Pb , are reported. Pa and Pb (R = H and ? OCH₃, respectively) showed blue photoluminescence emissions with quantum yields of more than 50% in toluene. In the solid state, Pa and Pb showed photoluminescence maximum emission peaks at 479 and 475 nm, respectively. Electrochemically, Pa and Pb showed good stability and reversibility under repeated electrochemical reduction. The polymers had glass‐transition temperatures higher than 90 °C and had 5 wt % loss temperatures higher than 400 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6554–6561, 2005     

Development of naphthalene and quinoxaline‐based donor–acceptor conjugated copolymers for delivering high open‐circuit voltage in photovoltaic devices

Two new quinoxaline‐based polymers, poly[1,5‐didecyloxynaphthalene‐alt‐5,5′‐(5,8‐dithiophen‐2‐yl)‐2,3‐bis(4‐octyloxyphenyl)quinoxaline (PNQx‐p) and poly[1,5‐didecyloxynaphthalene‐alt‐5,5′‐(5,8‐dithiophen‐2‐yl)‐2,3‐bis(3‐octyloxyphenyl)quinoxaline (PNQx‐m), were synthesized by Suzuki coupling reaction and characterized. Thermogravimetric analysis revealed that these polymers are thermally stable with degradation temperature up to 320 °C. As evident from the electrochemical and optical studies, the copolymers have comparable optical band gap (～2 eV) and nearly similar deep highest occupied molecular orbital (HOMO) energy levels of ?5.59 (PNQx‐p) and ?5.61 eV (PNQx‐p). The resulting copolymers possessed relatively low HOMO energy levels promising good air stability and high open circuit voltage (V_oc) for photovoltaic applications. The optimized photovoltaic device with a structure of ITO/PEDOT:PSS/PNQx‐m:PC₇₁BM (1:2, w/w)/LiF/Al shows a power conversion efficiency up to 2.29% with a short circuit current density of 5.61 mA/cm², an V_oc of 0.93 V and a fill factor of 43.73% under an illumination of AM 1.5, 100 mW/cm². The efficiency of the PNQx‐m polymer improved from 2.29 to 2.95% using 1,8‐diiodoocane as an additive (0.25%). © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and optoelectronic properties of conjugated polymers based on a dithienobenzimidazole unit in the main chain

Three conjugated polymers with the dithienobenzimidazole (DTBIm) unit ( P1 , P3 , and P4 ) and one conjugated polymer with the dithienobenzoxazole unit ( P2 ) were synthesized by the cross‐coupling polymerization. The absorption maxima showed a red‐shift in the order of P3 (406 nm), P2 (426 nm), P1 (438 nm), and P4 (450 nm), which was studied in detail using the frontier molecular orbital calculation of the model compounds. The energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the DTBIm unit‐containing conjugated polymers were estimated by the cyclic voltammetry. The transformation from DTBIm ( P4 ) to dithienobenzimidazolium ( P4' ) was also carried out to shift the absorption maxima of P4' (454 nm) by promoting the intramolecular charge transfer between the DTBIm and thiophene units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 401–409     

Pyrene‐cored covalent organic polymers by thiophene‐based isomers,their gas adsorption,and photophysical properties

Two new pyrene‐cored covalent organic polymers (COPs), CK‐COP‐1 and CK‐COP‐2 , were synthesized via the one‐step polymerization of two thiophene‐based isomers, 1,3,6,8‐tetra(thiophene‐2‐yl) pyrene ( L₁ ) and 1,3,6,8‐tetra(thiophene‐3‐yl) pyrene ( L₂ ). The resulting pyrene‐cored COPs exhibit rather different surface areas of 54 m² g^?1 and 615 m²g^?1 for CK‐COP‐1 and CK‐COP‐2 , respectively. The CO₂ uptake capacities of CK‐COP‐1 and CK‐COP‐2 also show different values of 2.85 and 9.73 wt % at 273 K, respectively. Furthermore, CK‐COP‐2 offers not only a larger CO₂ adsorption capacity but also a better CO₂/CH₄ selectivity at 273 K compared with CK‐COP‐1 . CK‐COP‐1 and CK‐COP‐2 also exhibit considerable differences in their photophysical property. The different structure and properties of CK‐COPs could be attributed to the isomer effect of their corresponding thiophene‐based monomers. © 2017 Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2383–2389     

Synthesis and characterization of novel poly(p‐phenylenevinylene) derivatives containing phenothiazine‐5‐oxide and phenothiazine‐5, 5‐dioxide moieties

PPV‐based copolymers containing phenothiazine‐5‐oxide and phenothiazine‐5, 5‐dioxide moieties have been successfully synthesized by Wittig‐Horner reaction and characterized by means of UV‐vis, photoluminescence, electroluminescence spectra, and cyclic voltammetry. All of these copolymers can be dissolved in common organic solvents such as chloroform, tetrahydrofuran, and toluene. The PL maxima in the film state are located at 582, 556, and 552 nm for P1, P2, and P3, respectively. The HOMO and LUMO levels of P2 are found to be ?5.21 and ?2.68 eV, respectively; whereas those of P3 are found to be ?5.26 and ?2.71 eV, respectively. The cyclic voltammetry result indicates that the conversion of electron‐donating sulfide to electron‐withdrawing sulfoxide or sulfone group in polymers plays a dominating role in increasing its oxidation potential. Yellowish‐green light ranging from 568 to 540 nm was observed for the single layer device with the configuration of ITO/Polymer/Ca/Al. Double layer devices with Zn (BTZ)₂ as a hole blocking layer exhibited enhanced EL performance compared to the single layer devices. The maximum brightness of the double layer devices of P1, P2, and P3 is 278, 400, and 796 cd/m², respectively. The results of EL and electrochemical analyses revealed that they are promising candidate materials for organic, light‐emitting diodes with hole‐transporting ability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4291–4299, 2007     

Conjugated copolymers comprised cyanophenyl‐substituted spirobifluorene and tricarbazole‐triphenylamine repeat units for blue‐light‐emitting diodes

A series of conjugated blue‐light‐emitting copolymers, PTC‐1 , PTC‐2 , and PTC‐3, comprised different ratios of electron‐withdrawing segments (spirobifluorene substituted with cyanophenyl groups) and electron‐donating segments (tricarbazole‐triphenylamines), has been synthesized. The structures of these polymers were characterized and their thermal, photophysical, electrochemical, and electroluminescence properties were measured. Incorporation of rigid spirobifluorene units into the copolymers led to blue‐shifted absorption peaks in dilute toluene solution. Cyclic voltammetric measurement indicated the bandgaps of the polymers were in the range of 2.77–2.94 eV. It was found that increasing cyanophenyl‐spirobifluorene content in the polymer backbone lowered both the HOMO and LUMO energy levels of the copolymers, which was beneficial for electron injection/transporting in the polymer layer of the device. OLED device evaluation indicated that all the polymers emitted sky blue to deep blue light when the pure polymers were used as the emissive layers in the devices with a configuration of ITO/PEDOT:PSS/polymers/CsF/Ca/Al. The devices have been optimized by doping 30 wt % PBD into the polymer layers. Among the doped devices, PTC‐2 showed the best performance with the turn‐on voltage of 3.0 V, maximum brightness of 7257 cd/m², maximum current efficiency of 1.76 cd/A, and CIE coordinates of (0.15, 0.14). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 292–301, 2010