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1.
Jacky Wing Yip Lam Junwu Chen Charles Chi Wang Law Han Peng Zhiliang Xie Kevin Ka Leung Cheuk Hoi Sing Kwok Ben Zhong Tang 《Macromolecular Symposia》2003,196(1):289-300
Linear polyacetylenes and hyperbranched polyphenylenes carrying 1,2,3,4,5-pentaphenylsilolyl (PS) pendants are designed and synthesized. Homo-polymerization of HC≡CPS, HC≡C(CH2)9OPS, and C6H5C≡C(CH2)9OPS and (co)polycyclotrimerization of (HC≡C)2PS with 1-octyne are effected by NbCl5-, WCl6-, MoCl5-, and TaCl5-based catalysts. High molecular weight linear ( 1-3 ) and hyperbranched polymers (6) are obtained in high yields (Mw up to ∼70 × 103 and yield up to 85%). All the polymers are thermally stable, losing little weight when heated to 350°C. Whereas all the polymers emit faint light when molecularly dissolved, polymers 2 , 3 , and 6 become emissive when aggregated in poor solvents or when cooled to low temperatures. Restricted intramolecular rotations of the phenyl rings upon the axes of the single bonds linked to the silole cores may be responsible for the aggregation- or cooling-induced emission. A multilayer electroluminescent device using 3 as an active layer emits a blue light of 496 nm with maximum brightness, current efficiency, and external quantum yield of 1118 cd/m2, 1.45 cd/A, and 0.55%, respectively. Polymers 6 are non-linear optically active and strongly attenuate the optical power of intense laser pulses, whose optical limiting performances are superior to that of C60, a best-known optical limiter. 相似文献
2.
Matthias Häußler Jianzhao Liu Jacky Wing Yip Lam Anjun Qin Ronghua Zheng Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2007,45(18):4249-4263
New aromatic diyne monomers of 1,4‐diethynyl‐2,5‐(dihexyloxy)benzene ( 1 ), 1,6‐diethynyl‐2‐(hexyloxy)naphthalene ( 2 ), and 9,9‐bis(4‐ethynylphenyl)fluorene ( 3 ) are synthesized. Their homopolymerizations and copolymerizations with 1‐octyne ( 4 ) or phenylacetylene ( 5 ) are effected by TaBr5–Ph4Sn and CpCo(CO)2–hν, giving soluble hyperbranched polyarylenes with high molecular weights (Mw up to ~ 2.9 × 105) in high yields (up to 99%). The structures and properties of the polymers are characterized and evaluated by IR, NMR, UV, PL, and TGA analysis. The polymers show excellent thermal stability (Td > 400 °C) and carbonize when pyrolyzed at 900 °C. Upon photoexcitation, the polymers emit deep blue light in the vicinity of ~400 nm with fluorescence quantum yields up to 92%. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4249–4263, 2007 相似文献
3.
Xin Wang Yongxin Yan Tianbao Liu Xinyan Su Liwu Qian Yinglin Song Hongyao Xu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5498-5504
A series of random copolymers poly(3‐ethynylthiophene)‐copoly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) with different oxadiazole content ( P2 – P4 ) and homopolymer poly(3‐ethynylthiophene) ( P1 ) as well as poly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) ( P5 ) were prepared. The copolymers ( P2 – P4 ) are completely soluble in common organic solvents. The structures and properties of all polymers were characterized and evaluated by FTIR, 1H NMR, 13C NMR, TGA, UV, PL, GPC, and nonlinear optical (NLO) analyses. The incorporation of diaryl‐oxadiazole into polyacetylene‐containing thiophene significantly endows copolymers with higher thermal stability, which may origin from the synergetic effect of the “jacket effect” of diaryl‐oxadiazole units and the effect of retarding or eliminating a few 6π‐electrocycliaztion proceeds of oxadiazole‐containing polyacetylene due to the hindrance of thiophene units. When the copolymer ( P3 ) posses more regular alternating thiophene pendants and oxadiazole pendants arrangement along the polymer backbone, it shows good thermal stability (Td up to 388 °C) and larger third‐order nonlinear optical susceptibility (χ(3) up to 11.0 × 10?11 esu). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
4.
Shouchun Yin Hongyao Xu Xinyan Su Gang Li Yinlin Song Jackywingyip Lam Benzhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(7):2346-2357
Poly(1‐alkyne)s containing azobenzene pendant groups with different lengths of the spacer and terminal alkyloxy group {? [HC?C(CH2)mOCO? C6H4? N?N? C6H4? OCpH2p+1]n? , where m = 1, 2, 3, or 9 and p = 4, 7, or 12} were synthesized in satisfactory yields with the [Rh(nbd)Cl]2–Et3N catalyst. All the polymers were soluble in common organic solvents such as CHCl3 and tetrahydrofuran. Their structures and properties were characterized and evaluated with IR, NMR, thermogravimetric analysis, UV, and optical‐limiting and nonlinear optical analyses. All the polymers were thermally stable and decomposed at temperatures as high as ~300 °C. The optical‐limiting and nonlinear optical properties of the polymers were sensitive to their molecular structures. Polymers having shorter spacer lengths and longer terminal groups showed better performances and larger third‐order nonlinear optical susceptibility (up to 1.34 × 10?10 esu). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2346–2357, 2006 相似文献
5.
Summary: Alkyne copolycyclomerizations of aromatic diynes 2,7‐bis(4‐ethynylphenylethynyl)‐9,9‐dihexylfluorene ( I ) and 1,4‐bis(4‐ethynylphenylethynyl)benzene ( II ) with an aliphatic monoyne 1‐dodecyne ( A ) were effected by CpCo(CO)2 hv in THF, producing hyperbranched poly(aryleneethynylene)s ( 1 and 2 ) of high molecular weights ( up to 4.4 × 104 Da) in high isolation yields (up to 97%). The polymers possessed outstanding thermal stability and emitted strong deep blue light of ≈400 nm when their solutions were photoexcited. The polymers effectively limited the light of a 532 nm laser, with the performance of 2 being better than that of C60, a well‐known optical limiter, under similar linear transmittance.
The structure of hyperbranched poly(aryleneethynylene). 相似文献
6.
Yu Liu Yunhe Zhang Shaowei Guan Haibo Zhang Xigui Yue Zhenhua Jiang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(22):6269-6279
Novel anhydride‐terminated fluorinated hyperbranched polyimides (FHBPIs) were successfully prepared by condensation of a triamine monomer, 1,3,5‐tris(2‐trifluoromethyl‐4‐aminopheoxy) benzene (TFAPOB), and various aromatic dianhydride monomers with different linear length. UV–vis spectra indicate high optical transparency of FHBPI films with a UV–vis absorption edge of 350–395 nm. FHBPIs show increased mechanical properties with the linear length of dianhydride monomer. Young's moduli of FHBPI range from 2.37 to 2.56 Gpa, similar to those of their linear analogs. These FHBPI films also present a minimum birefringence value as low as 0.0025 at 650 nm and have low optical absorption in the optical communication wavelengths of 1310 and 1550 nm. Rib‐type optical waveguide device fabricated by FHBPI‐4d demonstrated an obvious near‐field mode pattern of the waveguide. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6269–6279, 2009 相似文献
7.
Lin‐Ren Tsai Chia‐Wei Li Yun Chen 《Journal of polymer science. Part A, Polymer chemistry》2008,46(17):5945-5958
Linear polyfluorenes with low generation of side benzylether dendrons ( PLG0 , PLG1 ) and hyperbranched polyfluorenes with 1,3,5‐benzene branch unit ( PHG0 and PHG1 ) were prepared by the Suzuki coupling reaction to investigate the structural effect on optoelectronic properties. Their optical properties, both in solution and film state, were investigated using absorption and photoluminescence (PL) spectra. The excimer emission of polyfluorene at about 530 nm, induced by thermal annealing, was completely suppressed by the hyperbranched structure, but the suppression was not obvious by the side benzylether dendrons. The optoelectronic performance of the EL devices (ITO/PEDOT:PSS/polymer/Ca/Al) was strongly dependent upon chemical structures of the emitting polyfluorenes. The hyperbranched PHG0 with zero generation of benzylether side groups revealed the best device performance, with maximal luminance and maximal luminance efficiency of 2350 cd/m2 and 0.33 cd/A, respectively. The results suggest that incorporation of branch units with low generation of benzylether dendrons is an effective way to improve annealing stability and EL performance of the polyfluorenes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5945–5958, 2008 相似文献
8.
S. M. Abdul Karim Ryoji Nomura Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2002,40(14):2458-2463
Acetylenes containing salicylideneaniline groups—N‐salicylidene‐3‐ethynylaniline ( 1 ), N‐(3‐t‐butylsalicylidene)‐3‐ethynylaniline ( 2 ), and N‐(3‐t‐butylsalicylidene)‐4‐ethynylaniline ( 3 )—polymerized smoothly and gave yellow to red polymers in excellent yields when a rhodium catalyst was employed. Polymers with alkyl substituents on the aromatic rings [poly( 2 ) and poly( 3 )] were soluble in CHCl3, tetrahydrofuran, and so forth, whereas the polymer without alkyl substituents [poly( 1 )] was insoluble in any solvent. N‐(3‐t‐Butylsalicylidene)propargylamine did not provide any polymer. Thermogravimetric analyses of the resultant polymers exhibited good thermal stability (To, onset temperature of weight loss > 300 °C). The ultraviolet–visible spectra of the polymers showed absorption maxima and cutoff wavelengths around 360 and 520 nm, respectively. The polymers exhibited largely Stokes‐shifted fluorescence (emission wavelength ? 550 nm) upon photoexcitation at 350 nm, which resulted from the photoinduced intramolecular proton transfer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2458–2463, 2002 相似文献
9.
采用2,7-二(4-羟基苯基)-9,9-二烷基芴(A2)与四对甲基苯磺酸季戊四醇酯(B4)通过A2+B4型缩聚反应合成了一系列共轭型超支化聚合物.利用紫外和荧光谱对聚合物予以表征,结果表明,此类聚合物均可发出稳定、纯正的蓝光.DSC和TGA显示,4种聚合物在150℃以下没有明显的相态变化,300℃以内无明显的热分解现象,这表明此类聚合物具有良好的热稳定性,有利于材料的发光效率及发光稳定性. 相似文献
10.
Jianda Xie Lihua Hu Wenfang Shi Xiaoxu Deng Zhuangqi Cao Qishun Shen 《Journal of Polymer Science.Polymer Physics》2008,46(12):1140-1148
The hyperbranched polytriazole (hb‐PTA) containing second‐order nonlinear optical chromophore was synthesized through “A2 + B3” approach based on “click reaction.” Its corresponding linear analogue (l‐PTA) was prepared for comparison. The hb‐PTA has better solubility in common organic solvents than the l‐PTA. Both the polymers exhibit good thermal stability with 5% weight loss temperatures over 260 °C. The poled film of hb‐PTA exhibits much higher second‐harmonic coefficient (96.8 pm/V) than that of l‐PTA (23.5 pm/V). The three‐dimensional spatial isolation effect resulting from the highly branched structure and the crosslinking of the terminal acetylene groups at moderate temperature play important roles in the enhancement of optical nonlinearity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1140–1148, 2008 相似文献
11.
Novel functional hyperbranched poly(aryl ether ketone)s(HPAEKs) bonded with nonlinear optical chromophores(meso-tetrakis(4-hydroxyphenyl) porphyrin, THPP and its metal derivatives) were synthesized and characterized by 1H-NMR and UV-Vis absorption spectra. The incorporation of chromophores into HPAEKs endowed HPAEKs novel NLO and OL properties. Indeed, dendritic architecture allowed for maximum dispersion of the chromophores, avoided aggregation, more optical limiting property was obtained. Simultaneously, they retained the excellent properties of the materials, particularly in thermal stability. Their optical properties were evaluated by nonlinear optical analyses and optical limiting. The results showed that these polymers possessed good optical limiting(OL) property and large nonlinear optical(NLO) susceptibilities(ca. 10 12esu). All polymers containing chromophores presented excellent thermal stability(DT5 524.17 °C). 相似文献
12.
13.
Jianli Hua Jacky Wing Yip Lam Xiaoming Yu Lijun Wu Hoi Sing Kwok Kam Sing Wong Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(6):2025-2037
Perylene (Py)‐containing polyacetylenes with different skeleton structures ? [HC?C(C6H4)CO2? Py]n? (P 1 ), ? [HC?C(CH2)8CO2? Py]n? (P 2 ), and ? {[(C6H5) C?C(CH2)9NH2]? co? [(C6H5)C?C(CH2)9? Py]}n? (P 3 ) are synthesized in satisfactory yields by Rh‐catalyzed polymerization (for P 1 and P 2 ) and polymer reaction (for P 3 ). All the polymers are soluble and possess high molecular weights (Mw up to 2.8 × 105). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 μA/cm2. The external quantum efficiency is sensitive to the polymer structure, with P 3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025–2037, 2008 相似文献
14.
Ken Maruyama Hiroto Kudo Takayuki Ikehara Nobuhito Ito Tadatomi Nishikubo 《Journal of polymer science. Part A, Polymer chemistry》2005,43(19):4642-4653
Hyperbranched polyesters with terminal methacryloyl groups (HBPEAc) were synthesized by the one‐pot polyaddition of bisphenol A diglycidyl ether and trimesic acid in the presence of methacrylic acid with a number‐average molecular weights of 5100–7700 in 70–83% yields. The photoradical polymerization of HBPEAc was examined in the presence of 2‐methyl‐1‐[4‐(methylthio)phenyl]‐2‐morpholinopropan‐2‐one (Irgacure 907®) as a photoinitiator in the film state upon UV irradiation to afford the corresponding cured films quantitatively. The crosslinking densities of the cured films of HBPEAc were higher than those of the corresponding linear ones, and birefringence cannot be detected for the cured films of HBPEAc because of their random structures. Furthermore, an alkaline‐developable hyperbranched polyester containing pendant carboxyl groups (HBPEAc‐COOH) was prepared by the addition reaction of HBPEAc with cis‐1,2,3,6‐tetrahydrophthalic anhydride, and its patterning properties were examined to give the resolution of a 55‐μm‐line and 275‐μm‐space pattern by UV irradiation with 700 mJ/cm2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4642–4653, 2005 相似文献
15.
Erwin Abdul Rahim Fumio Sanda Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2006,44(2):810-819
Novel optically active amino acid based polyacetylenes bearing eugenol and fluorene moieties were synthesized, and their properties, including chiroptical ones, were analyzed. N‐[1‐(3,4‐Dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine N′‐propargylamide ( 1 ), N‐[1‐(3,4‐dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine propargyl ester ( 2 ), N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine N′‐propargylamide ( 3 ), and N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine propargyl ester ( 4 ) were polymerized with a rhodium‐zwitterion catalyst in tetrahydrofuran to afford the corresponding polymers with moderate molecular weights ranging from 10,800 to 17,300 in good yields. Because of the large specific rotation and circular dichroism (CD) signal, it was concluded that the poly(N‐propargylamide)s [poly( 1 ) and poly( 3 )] took a helical structure with a predominantly one‐handed screw sense. The solvent and temperature could tune the helical structure of poly( 1 ). On the other hand, the poly(propargyl ester)s [poly( 2 ) and poly( 4 )] exhibited only small specific rotations and CD signals. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 810–819, 2006 相似文献
16.
Mahalingam Vanjinathan A. Shanavas A. Raghavan A. Sultan Nasar 《Journal of polymer science. Part A, Polymer chemistry》2007,45(17):3877-3893
Starting from 3,5‐diamino benzoic acid, 2‐hydroxy propyl[3,5‐bis{(benzoxycarbonyl)imino}]benzyl ether, an AB2‐type blocked isocyanate monomer with flexible ether group, and 2‐hydroxy propyl[3,5‐bis{(benzoxycarbonyl)imino}]benzoate, an AB2‐type blocked isocyanate monomer with ester group, were synthesized for the first time. Using the same starting compound, 3,5‐bis{(benzoxycarbonyl)imino}benzylalcohol, an AB2‐type blocked isocyanate monomer, was synthesized through a highly efficient short‐cut route. Step‐growth polymerization of these monomers at individually optimized experimental conditions results in the formation of hyperbranched polyurethanes with and without ether and ester groups. Copolymerizations of these monomers with functionally similar AB monomers were also carried out. The molecular weights of the polymers were determined using GPC and the values (Mw) were found to vary from 1.5 × 104 to 1.2 × 106. While hyperbranched polyurethanes having no ether or ester group were found to be thermally stable up to 217 °C, hyperbranched poly(ether–urethane)s and poly(ester–urethane)s were found to be thermally stable up to 245 and 300 °C, respectively. Glass transition temperature (Tg) of polyurethane was reduced significantly when introducing ether groups into the polymer chain, whereas Tg was not observed even up to 250 °C in the case of poly(ester–urethane). Hyperbranched polyurethanes derived from all the three different AB2 monomers were soluble in highly polar solvents and the copolymers showed improved solubility. Polyethylene glycol monomethyl ether of molecular weight 550 and decanol were used as end‐capping groups, which were seen to affect the thermal, solution, and solubility properties of polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3877–3893, 2007 相似文献
17.
Jong‐Beom Baek Frank W. Harris 《Journal of polymer science. Part A, Polymer chemistry》2004,42(24):6318-6330
A phenylquinoxaline (PQ) AB monomer mixture was treated with monofunctional and difunctional end‐capping agents and with and without a coupling agent to afford phenylethynyl‐terminated linear PQ oligomers. The resulting PQ oligomers were soluble in common organic solvents and had intrinsic viscosities (IVs) of 0.21–0.30 dL/g. The glass‐transition temperature (Tg) of the diphenylethynyl‐end‐capped PQ oligomer on both sides increased the most, from 215 °C (before curing) to 251 °C (after curing). The PQ AB2 monomer, which acted as both a coupling agent and a monomer for the hyperbranched polymer, was treated with an AB monomer and end‐capping agents to afford phenylethynyl‐terminated hyperbranched polyphenylquinoxalines (PPQs). They were also soluble in common organic solvents, had IVs of 1.00–1.65 dL/g and Tg's of 251–253 °C, and underwent exothermic cure with maxima around 412–442 °C. The Tg's of the cured hyperbranched PPQs ranged from 258 to 261 °C, depending on the number of phenylethynyl groups on the surface. After further curing, they displayed a Tg of 316 °C in one sample and turned into a fully crosslinked network. The dynamic melt viscosities of a linear oligomer (IV = 0.21 dL/g), a hyperbranched sample (IV = 1.00 dL/g), and a linear reference PPQ (IV = 1.29 dL/g) were compared with respect to the processing temperature. The PQ oligomer and hyperbranched PPQ had low melt viscosities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6318–6330, 2004 相似文献
18.
Qu J Katsumata T Satoh M Wada J Igarashi J Mizoguchi K Masuda T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(28):7965-7973
The 2,2,6,6-tetramethyl-1-piperidinoxy (TEMPO)-containing acetylenic monomers HC[triple bond]CC(6)H(3)-p,m-(CONH-4-TEMPO)(2) (1), HC[triple bond]CC(6)H(3)-p,m-(COO-4-TEMPO)(2) (2), (S,S,S,S)-HC[triple bond]CC(6)H(3)-p,m-[CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO)](2) (3), (S,S)-HC[triple bond]CC(6)H(4)CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO) (4), HC[triple bond]CC(6)H(4)-p-OCO-4-TEMPO (5), HC[triple bond]CCH(2)C(CH(3))(CH(2)OCO-4-TEMPO)(2) (6), HC[triple bond]CCH(2)NHCO-4-TEMPO (7), and HC[triple bond]CCH(2)OCO-4-TEMPO (8) were polymerized to afford novel polymers containing the TEMPO radical at high densities. Monomers 1, 3-6, and 8 provided polymers with average molecular weights of 10 000-136 500 in 62-99 % yield in the presence of a rhodium catalyst, whereas monomers 2 and 7 gave insoluble polymers in 100 % yield. The formed polymers were thermally stable up to approximately 274 degrees C according to thermogravimetric analysis (TGA). All the TEMPO-containing polymers demonstrated reversible charge/discharge processes, whose discharge capacities were 21.3-108 A h kg(-1). In particular, the capacity of poly(1)-, poly(4)-, and poly(5)-based cells reached 108, 96.3, and 89.3 A h kg(-1), respectively, which practically coincided with their theoretical values. 相似文献
19.
Chun‐Hao Huang Sheng‐Hsiung Yang Kuei‐Bai Chen Chain‐Shu Hsu 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):519-531
Five novel fluorene‐containing polymers, poly[(9,9‐dimethylfluoren‐2‐yl)acetylene] ( PFA1 ), poly[(1‐pentyl‐2‐(9,9‐dimethylfluoren‐2‐yl)acetylene) ( PFA2 ), poly[1‐decyl‐2‐(9,9‐dimethylfluoren‐2‐yl)acetylene] ( PFA3 ), poly[1‐phenyl‐2‐(9,9‐dimethylfluoren‐2‐yl)acetylene] ( PFA4 ), and poly[1‐(3,4‐difluorophenyl)‐2‐(9,9‐dimethylfluoren‐2‐yl)acetylene] ( PFA5 ) were synthesized by the polymerization of the corresponding fluorene‐substituted acetylenic monomers ( M1–M5), using WCl6, MoCl5, and TaCl5 as catalysts and n‐Bu4Sn as a cocatalyst. The synthesized polymers were thermally stable and readily soluble in common organic solvents. The degradation temperatures for a 5% weight loss of the polymers were ∼352–503 °C under nitrogen. PFA1–PFA5 show emission peaks from 402 to 590 nm. Besides, their electroluminescent properties were studied in heterostructure light‐emitting diodes (LEDs), using PFA2–PFA5 as an emitting layer. The PFA5 device revealed an orange‐red emission peak at 602 nm with a maximum luminescence of 923 cd/m2 at 8 V. A device with the ITO/PEDOT/ a mixture of PFA2 (98 wt %) and PFA5 (2 wt %)/Ca/Al showed near white emission. Its maximum luminance and current efficiency are 450 cd/m2 at 15 V and 1.3 cd/A, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 519–531, 2006 相似文献
20.
Rui Wang Wei‐Zhi Wang Gui‐Zhong Yang Tianxi Liu Junsheng Yu Yadong Jiang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(3):790-802
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 相似文献