Co-reporter:Jiajia Wang, Junfeng Zhou, Kaikai Jin, Liang Wang, Jing Sun, and Qiang Fang
Macromolecules December 12, 2017 Volume 50(Issue 23) pp:9394-9394
Publication Date(Web):November 21, 2017
DOI:10.1021/acs.macromol.7b02000
A novel fluorinated macromonomer (TFVE-Si) with four functional groups derived from easily available tetraethoxysilane (TEOS) has been successfully synthesized through the Piers–Rubinsztajn reaction using B(C6F5)3 as a catalyst. This procedure efficiently avoids the generation of Si–OH and −Si–CH2–CH2– groups, which greatly affect the properties of the organosiloxanes. Prepolymerizing the macromonomer in mesitylene solution gives an oligomer which can form a flexible and highly transparent free-standing cross-linked polysiloxane film followed by a postpolymerization procedure at high temperature. The cross-linked polysiloxane (thickness = 2 mm) shows a transmittance of higher than 91% in the visible region and an absorbance of near 100% in the UV region (<350 nm), exhibiting its potential application as a transparent coating for blocking ultraviolet rays in both household and industrial uses. In particular, the cross-linked film shows low dielectric constant (Dk) of 2.50 and low dissipation factor (Df) of 4.0 × 10–3 at an ultrahigh frequency of 10 GHz. This is the first example of nonporous polysiloxane having both low Dk and Df while conventional TEOS-based polymers exhibit higher Dk (>3.0). Moreover, D–E loop tests illustrate that the cross-linked polysiloxane possesses excellent linear dielectric properties, further suggesting its good insulating properties. Furthermore, the prepared polysiloxane exhibits high thermostability with a 5 wt % loss temperature of 476 °C and a glass transition temperature (Tg) of 110 °C as well as good mechanical strength (with an elastic modulus of 1.1 GPa). Because of the existence of fluoro-containing groups, the polysiloxane also shows high hydrophobicity. Furthermore, TFVE-Si can efficiently improve the Tg of linear polysiloxane prepared from dimethylsiloxane with two functional groups. These indicate that the fluorinated TEOS has potential application in the microelectronics industry; especially, it can meet the requirement of the high-frequency communication fields for the materials with both low Dk and Df.
Co-reporter:Jiajia Wang, Jing Sun, Junfeng Zhou, Kaikai Jin, and Qiang Fang
ACS Applied Materials & Interfaces April 12, 2017 Volume 9(Issue 14) pp:12782-12782
Publication Date(Web):March 23, 2017
DOI:10.1021/acsami.7b01415
A fluorinated and thermo-cross-linked polyhedral oligomeric silsesquioxane (POSS) has been successfully synthesized by thermal polymerization of a fluorinated POSS monomer having an inorganic silsesquioxane core and organic side chains bearing thermo-cross-linkable trifluorovinyl ether groups. This new inorganic–organic hybrid polymer shows high thermostability with a 5 wt % loss temperature of 436 °C, as well as good transparency (a sheet with an average thickness of 1.5 mm shows high transmittance of 92% varying from 400 to 1100 nm). Moreover, the polymer exhibits both low dielectric constant (<2.56) and low dissipation factor (<3.1 × 10–3) in a wide range of frequencies from 40 Hz to 30 MHz even at a high frequency of 5 GHz. The polymer also shows low water uptake (<0.04%) and low Dk (near 2.63) after immersing it in water at room temperature for 3 days. These data imply that this polymer is very suitable to be utilized as a high-performance dielectric material for fabrication of high-frequency printed circuit boards or encapsulation resins for integrated circuit dies in the microelectronic industry. Furthermore, this work also provides a route for the preparation of fluorinated POSS-based polymers.Keywords: dielectric constant; fluoropolymers; high-performance polymers; hydrophobicity; Polyhedral oligomeric silsesquioxane (POSS);
Co-reporter:Junfeng Zhou;Jiajia Wang;Jiaqing Zhao;Kaikai Jin;Jing Sun;Xiaojun Guo
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 39) pp:6173-6180
Publication Date(Web):2017/10/10
DOI:10.1039/C7PY01207A
A novel fluoropolymer having triazine rings and thermo-crosslinkable benzocyclobutene units is prepared by a facile phase transfer catalyzed interfacial polycondensation reaction between a diphenol and a dichloro-s-triazine. This is the first example of thermo-crosslinkable fluoropolymer containing triazine units. The polymer shows a high molecular weight (Mn) of more than 70 000, good solubility and film-forming ability, as well as high storage stability. When treated at a high temperature (>200 °C), the polymer easily converts to a crosslinked network, showing a low dielectric constant (Dk) of 2.58 at a range of frequencies from 0.1 to 30.0 MHz. The Dk does not exhibit obvious change as the temperature is raised from room temperature to 100 °C. Moreover, the crosslinked network exhibits a dielectric strength of 157.7 kV cm−1, which is comparable with that of a widely used resin poly(2,6-dimethyl-1,4-phenylene ether). D–E loop tests indicate that the cured polymer possesses linear dielectric properties. The cured polymer also exhibits high hydrophobicity, which endows the polymer with a low water uptake of 0.11% after immersing it in water at room temperature for 72 h. Moreover, the crosslinked network exhibits high thermo-stability with a glass transition temperature of 264 °C and a 5 wt% loss temperature of 426 °C, as well as good mechanical properties with an average hardness of 0.48 GPa and an average Young's modulus of 11.92 GPa. These results suggest that this fluoropolymer having triazine units is better than those prepared from cyanate esters because the new polymer exhibits not only good dielectric properties, high thermostability and low water uptake, but also possesses high storage stability and good processability. Hence, this new fluoropolymer is suitable as a new dielectric matrix resin for the production of printed circuit boards used in the microelectronic industry.
Co-reporter:Yuanqiang Wang;Yijie Luo;Kaikai Jin;Jing Sun
RSC Advances (2011-Present) 2017 vol. 7(Issue 31) pp:18861-18866
Publication Date(Web):2017/03/28
DOI:10.1039/C7RA01146F
A new spiro-centered thermopolymerizable fluorinated macromonomer is reported here. This four-functional macromonomer is synthesized by a convergent strategy, and shows a low melting point (93 °C) and good solubility in the common organic solvents. When heated to a high temperature, the macromonomer converts into a cross-linked network (PD1), which exhibits a Tg of near 316 °C and a 5% weigh loss at a temperature of 417 °C in N2. PD1 also shows a low dielectric constant (Dk = 2.58 at 30 MHz) and high hydrophobicity (a water contact angle of θ = 98°), as well as low water uptake (about 0.45%, kept in boiling water for 72 h). These results suggest that the macromonomer has a potential application in the production of the high performance polymers, in particular, it is very suitable for encapsulation resins or the coatings utilized in the microelectronics industry.
Co-reporter:Yangqing Tao;Fengkai He;Kaikai Jin;Jiajia Wang;Yuanqiang Wang;Junfeng Zhou;Jing Sun
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 13) pp:2010-2015
Publication Date(Web):2017/03/28
DOI:10.1039/C7PY00047B
Anethole, a naturally occurring aromatic compound which can be extracted abundantly from plants like star anise, fennel and basil, has been conveniently transformed to a functional monomer in an overall yield of 81% via a two-step procedure. The obtained monomer combines reactive benzocyclobutene and propylene groups, thus it can undergo thermo-polymerization to form a crosslinking network, showing a low dielectric constant (<2.64 in a range of frequencies varying from 0.1 to 30 MHz) and low water uptake (<0.20% in boiling water for 144 h). TGA and DSC data exhibit that the cross-linked network has a 5 wt% loss temperature of 455 °C in N2 and a Tg of 160 °C, respectively. These results indicate that the new polymer based on biorenewable anethole is comparable to the materials derived from petroleum. On the basis of the wide application of low dielectric constant materials in the microelectronic industry, this work would offer a new sustainable feedstock to organic low k materials. Moreover, this contribution also provides a new route to convert other aromatic natural products.
Co-reporter:Jiajia Wang, Kaikai Jin, Jing Sun and Qiang Fang
Polymer Chemistry 2016 vol. 7(Issue 20) pp:3378-3382
Publication Date(Web):25 Apr 2016
DOI:10.1039/C6PY00576D
A novel fluoro-containing dendrimeric macromolecule with cyclic siloxane as the core and aryl-trifluorovinyl-ether (–OCFCF2) units as the arms was reported. The macromolecule was easily converted to a cross-linked structure showing an ultra-low k value and low water uptake. In particular, the network also exhibited high thermostability and excellent transparency.
Co-reporter:Junfeng Zhou, Linxuan Fang, Jiajia Wang, Jing Sun, Kaikai Jin and Qiang Fang
Polymer Chemistry 2016 vol. 7(Issue 26) pp:4313-4316
Publication Date(Web):31 May 2016
DOI:10.1039/C6PY00788K
Post-functionalization of a commercial novolac resin by introducing thermo-crosslinkable trifluorovinylether groups as the side chains offers a new polymer, which can form a cross-linked network without releasing volatiles during thermal curing. The cured resin shows a lower dielectric constant and higher thermostability than those of most commercial novolac resins.
Co-reporter:Jiajia Wang, Yijie Luo, Kaikai Jin, Chao Yuan, Jing Sun, Fengkai He and Qiang Fang
Polymer Chemistry 2015 vol. 6(Issue 33) pp:5984-5988
Publication Date(Web):03 Jul 2015
DOI:10.1039/C5PY00823A
A novel organosiloxane containing a thermally cross-linkable benzocyclobutene group was successfully synthesized through a one-pot Grignard reaction procedure. The organosiloxane can be easily polymerized or copolymerized to form the oligomers which can be directly converted to cross-linked network structures with excellent thermostability and low dielectric constants, implying that the organosiloxane has potential application in the electrical and microelectronics industry.
Co-reporter:Song Tian, Jing Sun, Kaikai Jin, Jiajia Wang, Fengkai He, Shijun Zheng, and Qiang Fang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 22) pp:20437
Publication Date(Web):October 28, 2014
DOI:10.1021/am506019s
A new fluorinated poly(aryl ether) with reactive benzocyclobutene groups as the side chain was successfully synthesized. This polymer showed a number-average molecular weight (Mn) of 200 000 and had good solubility and film-forming ability. After being postpolymerized at high temperature (>200 °C), the polymer film converted to a cross-linked network structure, which was insoluble in the common organic solvents. Such results suggest that the postpolymerization is an efficient way to achive the balance between the solubility and the solvent resistance of the polymer. TGA data showed that the postpolymerized polymer had a 5 wt % loss temperature at 495 °C and a residual of 61% at 1000 °C under N2. The cross-linked film also exhibited good dielectric properties with an average dielectric constant of about 2.62 in a range of frequencies from 1 to 30 MHz. With regard to the mechanical properties, the cross-linked film had hardness, Young’s modulus, and bonding strength to a silicon wafer of 1.22, 8.8, and 0.89 GPa, respectively. These data imply that this new polymer may have potential applications in the electrical and microelectronics industry.Keywords: benzocyclobutene dielectric constant; fluorinated poly(aryl ether)s; postpolymerization; synthesis; thermostability
Co-reporter:Jiajia Wang, Kaikai Jin, Fengkai He, Jing Sun and Qiang Fang
RSC Advances 2014 vol. 4(Issue 77) pp:40782-40787
Publication Date(Web):14 Aug 2014
DOI:10.1039/C4RA07201D
A new polymer with low dielectric constant is reported here. This polymer contains a trifluoromethyl-substituted phenyl unit and a binaphthyl unit, and shows high thermostability with a glass transition temperature of 244 °C and a 5 wt% loss at temperature 518 °C under nitrogen. The polymer also exhibits good film-forming ability, and the formed films exhibit high hydrophobicity with a contact angle of 103.6° with water. In a range of frequencies from 1 to 25 MHz, the polymer reveals an average dielectric constants of about 2.56. In regard to the mechanical properties, the polymer film shows an average hardness of 0.37 GPa and a Young's modulus of 15.07 GPa. These results indicate that the polymer could be used as a varnish for enameled wire, sizing agents for high-performance carbon fiber, and the matrix resin for the production of laminated composites utilized in the printed-circuit-board (PCB) industry.
Co-reporter:Yuanqiang Wang, Jing Sun, Kaikai Jin, Jiajia Wang, Chao Yuan, Jiawei Tong, Shen Diao, Fengkai He and Qiang Fang
RSC Advances 2014 vol. 4(Issue 75) pp:39884-39888
Publication Date(Web):18 Aug 2014
DOI:10.1039/C4RA05898D
A fluorene-based monomer (FB) with thermally cross-linkable benzocyclobutene groups is reported here. This monomer showed good solubility in the common organic solvents and had a low melting point (128 °C). When being treated at high temperature (>200 °C), the monomer was converted to a cross-linked network structure (PFB). TGA data exhibited that PFB had high thermostability with a 5% weight loss temperature of 437 °C and 372 °C in N2 and air, respectively. Moreover, PFB showed a char yield of 47.6% at 1000 °C in N2. With regard to the electrical properties, PFB indicated an average of dielectric constants of about 2.7 ranging from 0.15 MHz to 30 MHz. All these results suggest that FB could be used as the varnish for insulating enameled wire in the electrical industry, and as encapsulation resins in the microelectronics industry.
Co-reporter:Chao Yuan, Jiajia Wang, Kaikai Jin, Shen Diao, Jing Sun, Jiawei Tong, and Qiang Fang
Macromolecules 2014 Volume 47(Issue 18) pp:6311-6315
Publication Date(Web):September 4, 2014
DOI:10.1021/ma501263c
A novel functional oligomer (Si-TFVE) with a siloxane backbone and thermally cross-linkable trifluorovinyl ether groups (−OCF═CF2) is reported here. When postpolymerized at high temperature, Si-TFVE converts to an amorphous cross-linked network (Si-PFCB), which shows a dielectric constant of 2.33 and dielectric loss below 2.1 × 10–3 at 30 MHz. Si-PFCB also shows excellent film uniformity with the surface roughness less than 5.79 nm over a 1 μm square area. Moreover, Si-PFCB shows high thermostability with a 5 wt % loss temperature of 472 °C and no obvious Tg below 350 °C. In regard to the mechanical properties, Si-PFCB has Young’s modulus, hardness, and bonding strength with silicon wafer surface of 10.06 GPa, 0.392, and 4.93 GPa, respectively. These results suggest that such oligomer is suitable for utilization in ultralarge scale integration circuits. In addition, this contribution provides a new route to prepare cross-linked organosiloxanes only by heating instead of using catalysts or initiators in the traditional procedures.
Co-reporter:Chao Yuan;Kaikai Jin;Kai Li;Shen Diao;Jiawei Tong
Advanced Materials 2013 Volume 25( Issue 35) pp:4875-4878
Publication Date(Web):
DOI:10.1002/adma.201302021
Co-reporter:Fengkai He, Chao Yuan, Kai Li, Shen Diao, Kaikai Jin, Jiajia Wang, Jiawei Tong, Juan Ma and Qiang Fang
RSC Advances 2013 vol. 3(Issue 45) pp:23128-23132
Publication Date(Web):30 Sep 2013
DOI:10.1039/C3RA44991B
A thermally cross-linkable molecule composed of bis(trifluoromethyl)benzene and benzocyclobutene units (F1) was successfully prepared. Heating F1 (>200 °C) gave a cured resin, which showed a dielectric constant (k) of 2.47 at 30 MHz and an average k value of less than 2.51 in a range of frequencies from 0.15 MHz to 30 MHz. Such low k values are comparable to other polymeric low-k materials. For comparison, a perfluorobenzene with benzocyclobutene groups (F2) was also synthesized. The cured F2 exhibited an average k value of 2.98, indicating that the introduction of a trifluoromethyl group into the backbone of the molecules can efficiently decrease the dielectric constant of the molecules. The cured F1 also exhibited high thermostability (T5 = 429 °C, weight residual = 47.7% at 1000 °C under N2). These results suggest that F1 is suitable for the utilization in ultra large scale integration circuits.
Co-reporter:Jia Hong, Hua Lai, Yanmei Liu, Chao Yuan, Yuxue Li, Ping Liu and Qiang Fang
RSC Advances 2013 vol. 3(Issue 4) pp:1069-1072
Publication Date(Web):21 Nov 2012
DOI:10.1039/C2RA22195K
Two new organic dyes containing E- or Z-trifluoromethyl acrylic acid as the electron acceptors were synthesized and used as sensitizers for dye-sensitized solar cells (DSSCs). The Z-isomer achieved a power conversion efficiency (η) of 4.05%, which was much higher than that of the E-isomer (η = 1.35%). Such results give a new insight into in design of new dyes for DSSCs.
Co-reporter:Xingpeng Chen, Kai Li, Shijun Zheng and Qiang Fang
RSC Advances 2012 vol. 2(Issue 16) pp:6504-6508
Publication Date(Web):15 May 2012
DOI:10.1039/C2RA20617J
A new type of unsaturated polyester resins (UP) with low dielectric constant (κ) and high thermostability was prepared by doping N-phenylmaleimides containing perfluoroalkyl substituents (–CF3 and –C6F13) into a commercial unsaturated polyester resin. In comparison with neat UP resin, the doped UP resins showed decreased dielectric constant and increased char yields. The best result was obtained when the substituent was –CF3, which gave a dielectric constant of 3.63 and 5 wt%, loss temperature of 336 °C with a char yield of 5.57% under N2. Such data are superior to those of neat UP resin, which showed dielectric constants of 4.38 and 5 wt%, a loss temperature of 327 °C with a char yield of 2.25% . In this contribution, a new environmentally-friendly procedure for the synthesis of the fluoro-containing maleimides was also provided, in which a Brønsted acidic room temperature ionic liquid was employed as a catalyst and the products were obtained through merely decanting and removal of the solvent.
Co-reporter:Hua Lai, Jia Hong, Ping Liu, Chao Yuan, Yuxue Li and Qiang Fang
RSC Advances 2012 vol. 2(Issue 6) pp:2427-2432
Publication Date(Web):02 Feb 2012
DOI:10.1039/C2RA01002J
Three new multi-carbazole derivatives (2C–4C) with a twisted and zigzag-shape structure were designed, synthesized and used as sensitizers for dye-sensitized solar cells (DSSCs). The results showed that this non-planar structure of 2C–4C, combined with multi alkyl chains, can efficiently inhibit dye aggregation and charge recombination, which gave DSSCs with a high open circuit voltage (Voc) and an overall solar-to-electric conversion efficiency (η) of up to 6.33%.
Co-reporter:Yifan Shan;Jie Tang;Hua Lai;Hongwei Tan;Xiaofeng Liu;Fan Yang
Chinese Journal of Chemistry 2012 Volume 30( Issue 7) pp:1497-1503
Publication Date(Web):
DOI:10.1002/cjoc.201200091
Abstract
Organic dyes with ethoxy-substituted oligo-phenylenevinylene as chromophores were synthesized for dye-sensitized solar cells (DSSCs), and the detailed relationships between the dye structures, photophysical properties, electrochemical properties, and performances of DSSCs were described. The dye S3O showed broad IPCE spectra in the spectral range of 350–750 nm, and the dye S1P showed solar energy-to-electricity conversion efficiency (() of up to 4.23% under AM 1.5 irradiation (100 mW/cm2) in comparison with the reference Ru-complex (N719 dye) with an η value of 5.90% under similar experimental conditions.
Co-reporter:Jia Jin, Yifan Shan, Fan Yang, Hua Lai, Hongwei Tan, Xiaofeng Liu, Jie Tang, Qiang Fang
Synthetic Metals 2012 Volume 162(Issue 24) pp:2222-2227
Publication Date(Web):31 December 2012
DOI:10.1016/j.synthmet.2012.11.001
Four new organic dyes with N-carboxymethyl pyridinium as electron acceptors/anchoring groups were designed and synthesized. The optical and electrochemical properties were characterized by UV–vis, fluorescence spectroscopy and cyclic voltammetry. The absorption spectra of the four pyridinium dyes were in the range of 450–650 nm. The dye with triphenylamine as the electron donor shows a solar-energy-to-electricity conversion efficiency (η) of 2.33% in comparison with the reference Ru-complex (N719 dye) with a η value of 5.45% under the same experimental conditions. The dye with phenoxazine as the electron donor gives broad IPCE spectra in the range of 400–750 nm. All these new dyes are simple in structure, very easy to synthesize, and gives high Voc.Graphical abstractHighlights► Four novel N-carboxymethyl pyridinium dyes were designed and synthesized. ► The new dyes are simple in structure, very easy to synthesize, and gives high Voc. ► CB1 obtained a η value of 2.33% (the reference Ru-complex N719 dye 5.45%).
Co-reporter:Yifan Shan, Jie Tang, Hua Lai, Hongwei Tan, Fan Yang, Qiang Fang, Pierre Audebert, Adam Pron
Tetrahedron Letters 2012 Volume 53(Issue 11) pp:1341-1344
Publication Date(Web):14 March 2012
DOI:10.1016/j.tetlet.2011.12.133
A novel organic dye with N-substituted pyridinium as the acceptor and carboxylate as the anchoring group were designed and synthesized for dye-sensitized solar cells, which give solar energy-to-electricity conversion efficiency (η) of up to 3.47% in comparison with the reference Ru-complex (N719 dye) with an η value of 5.27% under similar experimental conditions. This new dye is simple in structure, very easy to synthesize, and gives high Voc.
Co-reporter:Kai Li, Chao Yuan, Shijun Zheng, Qiang Fang
Tetrahedron Letters 2012 Volume 53(Issue 32) pp:4245-4247
Publication Date(Web):8 August 2012
DOI:10.1016/j.tetlet.2012.06.025
Seven maleimide derivatives were synthesized in good yields and high purity from the corresponding maleamic acids using a Brønsted acidic room temperature ionic liquid (RTIL) as a catalyst. The products were obtained through merely a decanting and removal of the solvent, suggesting that this procedure is superior to the conventional routes, in which the strong organic/inorganic acids were used as the catalysts, as well as a complicated post-processing procedure for the separation and purification of the products was employed.The pure product was obtained by merely a decanting and removal of the solvent. Additional six maleimides were also synthesized in good yields and high purity.
Co-reporter:Yanmei Liu;Hua Lai;Bo Rong;Tie Zhou;Jia Hong;Chao Yuan;Shujing Zhao;Xiaolong Zhao;Biao Jiang
Advanced Synthesis & Catalysis 2011 Volume 353( Issue 17) pp:3161-3165
Publication Date(Web):
DOI:10.1002/adsc.201100339
Abstract
An efficient strategy for a high-yielding and stereoselective synthesis of α-trifluoromethyl unsaturated carboxylic acids directly from the reactions of 3,3,3-trifluoropropanoic acid (CF3CH2COOH) with various aryl aldehydes in the presence of titanium tetrachloride (TiCl4) is reported here for the first time, which is a valuable expansion for the classical Knoevenagel reaction. Because these compounds may have potential applications in organic electronics and can be easily converted to the corresponding fluorinated alcohols and amino acids with excellent bioactivity, this route should be a good choice for the preparation of α-trifluoromethyl-containing derivatives.
Co-reporter:Jing Sun, Hua Lai, Hongliang Zhong, Qiang Fang
Thin Solid Films 2011 Volume 519(Issue 22) pp:7772-7778
Publication Date(Web):1 September 2011
DOI:10.1016/j.tsf.2011.06.019
Two oligomers with X-shaped repeating units bearing anthracene and fluorene units were synthesized in a facile procedure, and exhibited high photoluminescence efficiencies, thermal stabilities and good solubility. Their ease of processing enabled spin coating with an electron-transporting bitriazine layer to afford organic light-emitting diodes which displayed a light blue emission with the maximum luminance of 3650 cd/m2 and the current efficiency of 0.69 cd/A at an operation voltage of 10 V.
Co-reporter:Hongliang Zhong ; Hua Lai
The Journal of Physical Chemistry C 2011 Volume 115(Issue 5) pp:2423-2427
Publication Date(Web):December 21, 2010
DOI:10.1021/jp109806m
Two novel triazine-based compounds with efficient hole-blocking ability were designed and synthesized, which promoted the performance of electroluminescent devices, especially for PLED even when Al was applied as the cathode. The results indicated that introducing electron-donating groups and extending π-conjugated were facile methodologies to improve the optoelectronic properties of the triazine derivatives.
Co-reporter:Chao Yuan;Jia Hong;Yanmei Liu;Hua Lai
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 18) pp:4098-4101
Publication Date(Web):
DOI:10.1002/pola.24852
Co-reporter:Jing Sun, Hongliang Zhong, Erjian Xu, Danli Zeng, Jianhua Zhang, Hongguang Xu, Wenqing Zhu, Qiang Fang
Organic Electronics 2010 Volume 11(Issue 1) pp:74-80
Publication Date(Web):January 2010
DOI:10.1016/j.orgel.2009.09.030
A new X-shaped solution-processible oligomer with a glass transition temperature of higher than 200 °C based on an anthracene derivative was prepared, and it showed good hole-transporting ability in organic light-emitting diodes (OLED). Such oligomer was also employed as the emitting layer to give the devices showing blue emission.
Co-reporter:Yanmei Liu, Hua Lai, Hongliang Zhong, Erjian Xu, Junping Du, Yuxue Li, Qiang Fang
Tetrahedron Letters 2010 Volume 51(Issue 33) pp:4462-4465
Publication Date(Web):18 August 2010
DOI:10.1016/j.tetlet.2010.06.093
New ethylene-separated benzothiadiazoles were synthesized for the first time by using a facile procedure, and they showed lower bandgaps than the reported benzothiadiazole-containing compounds. This new benzothiadiazole-containing unit could be introduced into the backbone of the π-conjugated small molecules or polymers to develop new materials with a low bandgap that may have potential applications in optoelectronic fields.
Co-reporter:Erjian Xu;Hongliang Zhong;Hua Lai;Danli Zeng;Jianhua Zhang;Wenqing Zhu
Macromolecular Chemistry and Physics 2010 Volume 211( Issue 6) pp:651-656
Publication Date(Web):
DOI:10.1002/macp.200900486
Co-reporter:Shijie Ren, Danli Zeng, Hongliang Zhong, Yaochuan Wang, Shixiong Qian and Qiang Fang
The Journal of Physical Chemistry B 2010 Volume 114(Issue 32) pp:10374-10383
Publication Date(Web):July 22, 2010
DOI:10.1021/jp104710y
Monodispersed oligomers have been widely developed and used in different optoelectronic areas due to their well-defined molecular structures, high purity, and solution processability. Star-shaped oligomers are especially interesting for OLED application because of their antiaggregation abilities and stable electroluminescence. In addition, star-shaped donor-π-acceptor conjugated molecules are known to afford good nonlinear optical and two-photon absorption properties due to the intramolecular charge transfer and cooperative enhancement effects. In this context, three generations of highly soluble 1,3,5-triazine based donor-π-acceptor compounds, TFT1, TFT2, and TFT3, were prepared through a convergent synthetic strategy and their optoelectronic properties were fully studied, which showed distinct correlations with the structures. Closed-aperture and open-aperture Z-scan methods were employed to measure the nonlinear refractive index and two-photon absorption properties of the oligomers, respectively. TFT1 showed a high nonlinear refractive index of 4.14 × 10−12 esu in THF solution with an excitation wavelength of 800 nm. Also, TFT1 exhibited a large two-photon absorption cross section of 234 GM and a frequency up-converted two-photon excited fluorescence with a λTPEFmax value of 527 nm under 800 nm laser irradiation with a pulse duration of 140 fs. OLED devices using the spin-coated films of these oligomers as an active layer showed intensive blue electroluminescence with a maximum luminance of 3093 cd/m2 at a current efficiency of 1.47 cd/A from TFT1.
Co-reporter:Erjian Xu, Hongliang Zhong, Junping Du, Danli Zeng, Shijie Ren, Jing Sun, Qiang Fang
Dyes and Pigments 2009 Volume 80(Issue 1) pp:194-198
Publication Date(Web):January 2009
DOI:10.1016/j.dyepig.2008.07.008
A series of novel, 2,1,3-benzothiadiazole-based oligomers were synthesized by the self/cross-coupling reaction of monobromo-substituted benzothiadiazole compounds in a catalyst system comprising Pd(OAc)2/PEG (polyethylene glycol)/DMF. The oligomers displayed good linear correlation between Egopt (or λmax, abs or λmax, em) and the reciprocal of the numbers of the benzothiadiazole units. The LUMO values of the compounds decreased with increasing number of benzothiadiazole units on the backbone of the molecules.
Co-reporter:Shijie Ren, Jiangong Cheng, Danli Zeng, Wenqing Zhu, Jing Sun, Junping Du, Erjian Xu, Hongliang Zhong, Yingchun Liu, Qiang Fang
Synthetic Metals 2009 Volume 159(1–2) pp:29-35
Publication Date(Web):January 2009
DOI:10.1016/j.synthmet.2008.07.015
A new star-shaped polymer comprising of full fluorene units was synthesized by Suzuki polycondensation between an A3 type monomer and an AB type monomer. For comparison, a fluorene-based linear polymer was also prepared. The star-shaped polymer was soluble in common organic solvents and gave the number-average molecular weight, Mn, of more than 12,000 and the weight-average molecular weight, Mw, of exceeded 22,000. The polymer showed similar optical behavior both in solution and in the solid state. After an annealing process, the linear fluorene-based polymer showed an additional bathochromic emission at about 550 nm, whereas such red-shifted emission was fully eliminated for the fluorene-based star-shaped polymer. Cyclic voltammetry (CV) measurement of the polymer indicated that the polymer was reversible under p-doping.
Co-reporter:Junping Du;Erjian Xu;Hongliang Zhong;Feng Yu;Chang Liu;Huanrong Wu;Danli Zeng;Shijie Ren;Jing Sun;Yingchun Liu;Amin Cao
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 4) pp:1376-1387
Publication Date(Web):
DOI:10.1002/pola.22478
Abstract
Four new soluble polymers containing a 2,7-carbazole unit and a 2,1,3-benzothiadiazole unit in the main chain were synthesized by Suzuki polycondensation. Variation of the substituent groups (R) at 5-position of 2,1,3-benzothiadiazole unit resulted in different color emission of the copolymers. Thus, when R was CH3 (or H), the polymer showed yellow–green (or red) emission; whereas the polymers showed the emission from green to yellow–green, when R was CH2(CH2)5CH3 or CH2OCH(CH3)2. To investigate the nature of the color change, a Gaussian 03 program was used for estimation of the dihedral angles between a 5-R-2,1,3-benzothiadiazole unit and a 2,7-carbazole unit. The results showed that the different substituents at 5-position of 2,1,3-benzothiadiazole brought about different the dihedral angles, which gave the different conjugation levels to the polymers. Hence, the tunablity of emission color may be attributed to the different conjugation levels between 2,7-carbazole units and 5-R-2,1,3-benzothiadiazole units induced by simply changing substituent groups at 5-position of benzothiadiazole unit. Electrochemically, the copolymers exhibited a higher oxidation potential as well as the reversible reduction behavior bearing from 2,1,3-benzothiadiazole unit. To investigate the electroluminescent properties of the polymers, the nonoptimized devices were fabricated and the results showed that the electroluminescent emission wavelength was basically similar to that of the photoluminescent. All polymers showed good thermal stability with 5 wt % loss temperature of more than 296 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1376–1387, 2008
Co-reporter:Jing Sun;Jian-Gong Cheng;Wen-Qing Zhu;Shi-Jie Ren;Hong-Liang Zhong;Dan-Li Zeng;Jun-Ping Du;Er-Jian Xu;Ying-Chun Liu
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 16) pp:5616-5625
Publication Date(Web):
DOI:10.1002/pola.22883
Abstract
A new X-shaped π-conjugated monomer comprising of fluorene units and anthracene units was synthesized, and it was used to fabricate the new X-shaped π-conjugated polymers and investigate the properties of the new polymers. Using different molar ratios between such monomer and a fluorene monomer gave three polymers that showed higher absolute PL quantum yields than the linear polyfluorene (PF) in the solid state. After thermal annealing at 200 °C for 4 h, the linear PF showed an additional bathochromic emission at about 550 nm, whereas such red-shifted emission was fully eliminated for the X-shaped polymers. The electroluminescent devices based on the X-shaped polymers with a configuration of ITO/PEDOT:PSS/polymer/LiF/Ca/Al displayed blue emission with low turn-on voltage and high brightness. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5616–5625, 2008
Co-reporter:Danli Zeng, Jiangong Cheng, Shijie Ren, Jing Sun, Hongliang Zhong, Erjian Xu, Junping Du, Qiang Fang
Reactive and Functional Polymers (December 2008) Volume 68(Issue 12) pp:1715-1721
Publication Date(Web):December 2008
DOI:10.1016/j.reactfunctpolym.2008.10.001
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