- Carbazole/fluorene based conjugated small molecules: Synthesis and comparative studies on the optical, thermal and electrochemical properties
-
A series of new molecular materials with varying carbazole and fluorene contents were prepared employing Suzuki coupling and their properties were compared. A variation of the core nucleus from fluorene to carbazole was a key point to study its effect on the thermal, optical and electrochemical properties. The materials were characterized by FTIR, 1H-, 13C-NMR, APCI-MS and elemental microanalyses. The synthesized materials exhibit slightly bathochromic shifted UV/Vis spectra in dilute solution and emission maxima in the blue region along with good thermal stability. The dyes with a fluorene core are electrochemically and spectrally stable with high lying HOMO levels, in contrast to the carbazole only materials, having potential as light emitting and hole transporting materials in organic light emitting diodes.
- Irfan, Madiha,Belfield, Kevin D.,Saeed, Aamer
-
p. 48760 - 48768
(2015/06/16)
-
- Fluorene-based chemodosimeter for "turn-on" sensing of cyanide by hampering ESIPT and live cell imaging
-
A new salicylaldehyde appended fluorene-based chemodosimeter (FSal) has been designed by taking consideration of the special nucleophilicity of cyanide ion. FSal shows selective affinity towards CN- over other anions (namely F-, Br-, NO3-, ClO 4-, N3-, H2PO 4-, AcO-, I-, Cl-, and NO2-) through turn-on fluorescence with a minimum detection limit of 0.06 ppm. The turn-on fluorescence of the FSal-CN complex resulting from hampering ESIPT is also supported by DFT and TDDFT calculations. Biological compatibility and live cell imaging of this unique probe have also been explored.
- Bera, Manas Kumar,Chakraborty, Chanchal,Singh, Pradeep Kumar,Sahu, Chandan,Sen, Kaushik,Maji, Samir,Das, Abhijit Kumar,Malik, Sudip
-
p. 4733 - 4739
(2014/07/21)
-
- Poly(1,4-diketo-3,6-diphenylpyrrolo[3,4-c]pyrrole-alt-3,6-carbazole/2, 7-fluorene) as high-performance two-photon dyes
-
This article reports the synthesis, one- and two-photon absorption, and excited fluorescence properties of poly(1,4-diketo-3,6-diphenylpyrrolo[3,4-c] pyrrole-alt-N-octyl-3,6-carbazole/2,7-fluorene) (PDCZ/PDFL). PDCZ and PDFL are synthesized by the Suzuki
- Yang, Chao,Zheng, Meng,Li, Yiping,Zhang, Deteng,Xue, Shanfeng,Yang, Wenjun
-
p. 944 - 951
(2014/03/21)
-
- 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 A conjugated polymer based on 9,9'-dioctylfluorene and N-octyl substituted 2,2'-(1,4-phenylene)- bis(benzimidazole) moieties (PFBI8) was synthesized. Its solutions emit blue light efficiently, with the quantum yield up to 99% in chloroform. It is also morphologically and thermally stable, with glass transition temperature and decomposition temperature as high as 103 and 428 °C, respectively. The polymer light-emitting diode using PFBI8 as the active emitting layer exhibits blue emission (448 nm) with the maximum luminance, current efficiency and power efficiency of 1534 cd/m2, 0.67 cd/A, and 0.20 lm/W, respectively. Copyright
- Zhu, Haifeng,Tong, Hui,Gong, Yongyang,Shao, Shiyang,Deng, Chunmei,Yuan, Wang Zhang,Zhang, Yongming
-
experimental part
p. 2172 - 2181
(2012/07/17)
-
- π-conjugated chelating polymers with charged iridium complexes in the backbones: Synthesis, characterization, energy transfer, and electrochemical properties
-
A series of π-conjugated chelating polymers with charged iridium (Ir) complexes in the backbones were synthesized by a Suzuki polycondensation reaction, leading to homogeneous polymeric materials that phosphoresce red light. The fluorene and bipyridine (bpy) segments were used as polymer backbones. 5.5′-Dibromobipyridine served as a ligand to form a charged iridium complex monomer with 1-(9′9-dioctylfluorene-2-yl)isoquinoline (Fiq) as the cyclometalated ligand. Chemical and photophysical characterization confirmed that Ir complexes were incorporated into the backbones as one of the repeat units by means of the 5.5′-dibromobipyridine ligand. Chelating polymers showed almost complete energy transfer from the host fluorene segments to the guest Ir complexes in the solid state when the feed ratio was 2 mol%. In the films of the corresponding blend system, however, energy transfer was not complete even when the content of Ir complexes was as high as 16 mol%. Both intra- and in termolecular energy-transfer processes existed in this host-guest system, and the intramolecular energy transfer was a more efficient process. All chelating polymers displayed good thermal stability, redox reversibility, and film formation. These chelating polymers also showed more efficient energy transfer than the corresponding blended system and the mechanism of incorporation of the charged Ir complexes into the π-conjugated polymer backbones efficiently avoided the intrinsic problems associated with the blend system, thus offering promise in optoelectronic applications.
- Liu, Shu-Juan,Zhao, Qiang,Chen, Run-Feng,Deng, Yun,Fan, Qu-Li,Li, Fu-You,Wang, Lian-Hui,Huang, Chun-Hui,Huang, Wei
-
p. 4351 - 4361
(2008/02/06)
-
- Hyperbranched oxadiazole-containing polyfluorenes: Toward stable blue light PLEDs
-
The synthesis of hyperbranched oxadiazole-containg polyfluores using 'A2 + A2′ + B3' approach based on Suzuki polycondensation was investigated. The molecular structures of the sample polymer were characterized with high-resolution NMR spectroscopy and elemental analysis. The solubility was found to be poor in organic solvents for hyperbranched polymers with higher contents of 2-(4-bromophenyl)-5-(3,5-dibromophenyl)-1,3,4-oxadiazole monomer. The sample polyfluores showed stable blue light emission even after being annealed in the elevated temperatures in the N2 and air.
- Xin, Yu,Wen, Gui-An,Zeng, Wen-Jing,Zhao, Lei,Zhu, Xing-Rong,Fan, Qu-Li,Feng, Jia-Chun,Wang, Lian-Hui,Wei, Wei,Peng, Bo,Cao, Yong,Huang, Wei
-
p. 6755 - 6758
(2007/10/03)
-
- High-efficiency red-light emission from polyfluorenes grafted with cyclometalated iridium complexes and charge transport moiety
-
We report a new route for the design of electroluminescent polymers by grafting high-efficiency phosphorescent organometallic complexes as dopants and charge transport moieties onto alky side chains of fully conjugated polymers for polymer light-emitting diodes (PLED) with single layer/single polymers. The polymer system studied involves polyfluorene (PF) as the base conjugated polymer, carbazole (Cz) as the charge transport moiety and a source for green emission by forming an electroplex with the PF main chain, and cyclometalated iridium (Ir) complexes as the phosphorescent dopant. Energy transfer from the green Ir complex or an electroplex formed between the fluorene main chain and side-chain carbazole moieties, in addition to that from the PF main chain, to the red Ir complex can significantly enhance the device performance, and a red light-emitting device with the high efficiency 2.8 cd/A at 7 V and 65 cd/m2, comparable to that of the same Ir complex-based OLED, and a broad-band light-emitting device containing blue, green, and red peaks (2.16 cd/A at 9 V) are obtained. Copyright
- Chen, Xiwen,Liao, Jin-Long,Liang, Yongmin,Ahmed,Tseng, Hao-En,Chen, Show-An
-
p. 636 - 637
(2007/10/03)
-
- Synthesis and characterization of alternating copolymers of fluorene and oxadiazole
-
Alternating copolymers of 9,9-dioctylfluorene and oxadiazole have been prepared by the tetrazole route or the Suzuki coupling reaction. In the polymers the oxadiazole units were evenly dispersed in the main chain at every one, P(F1-alt-Ox), three, P(F3-alt-Ox), or four, P(F4-alt-Ox), fluorene units. Another copolymer with an asymmetric repeat unit structure, P(F3-Ox-F1-Ox) has also been prepared for comparison. In this study, the tetrazole route has been demonstrated to offer several advantages for preparing polyoxadiazole with well-defined structures compared to other oxadiazole ring formation reactions. These advantages include: clean and fast reactions, mild reaction conditions, high yields, and high molecular masses of product. The glass transition temperature of copolymers ranged from 98 to 150 °C, and the copolymers show high thermal stability with decomposition temperatures around 430 °C. The UV-vis absorption and photoluminescence properties of all the copolymers in solutions are similar to those of poly(9,9-dioctylfluorene). All copolymers fluoresce in the blue-light range with quantum yields of ~70% in CH2Cl2 solution.
- Ding, Jianfu,Day, Michael,Robertson, Gilles,Roovers, Jacques
-
p. 3474 - 3483
(2007/10/03)
-