Improving optoelectronic properties of the 2,7‐polyfluorene derivatives with carbazole and oxadiazole pendants by incorporating the blue‐emitting iridium complex pendants in C‐9 position of fluorine unit

To study the influence of a blue‐emitting iridium complex pendant on the optoelectronic properties of its 2,7‐polyfluorene (PF) derivatives with the carbazole and oxadiazole pendants, a class of 2,7‐PF derivatives containing carbazole, oxadiazole, and/without the cyclometalated iridium complex pendants in the C‐9 positions of fluorene unit were synthesized. Their thermal, photophysical, electrochemical, and electroluminescent (EL) properties were investigated. Among these 2,7‐PF derivatives (P 1 –P 4 ), P 2 and P 3 exhibited higher photoluminescence efficiency in dichloromethane and better EL properties in the single‐emissive‐layer polymer light‐emitting devices. The highest brightness of 3888 cd/m² and the maximum current efficiency of 2.9 cd/A were obtained in the P 2 ‐ and P 3 ‐based devices, respectively. The maximum brightness and efficiency levels were 1.7 and 2.1 times, respectively, higher than the corresponding levels from the parent 2,7‐PF derivative (P 1 )‐based devices. Our work indicated that EL properties of 2,7‐PF derivatives can be improved by introducing the blue‐emitting iridium complex into the alkyl side chain of fluorine unit as pendant. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

White electroluminescence from a single polyfluorene containing bis‐DCM units

A series of fluorene‐based copolymers composed of blue‐ and orange‐light‐emitting comonomers were synthesized through palladium‐catalyzed Suzuki coupling reactions. 9,9‐Dihexylfluorene and 2‐(2,6‐bis‐{2‐[1‐(9,9‐dihexyl‐9H‐fluoren‐2‐yl)‐1,2,3,4‐tetrahydroquinolin‐6‐yl]‐vinyl}‐pyran‐4‐ylidene)‐malononitrile (DCMF) were used as the blue‐ and orange‐light‐emitting chromophores, respectively. The resulting single polymers exhibited simultaneous blue (423/450 nm) and orange (580–600 nm) emissions from these two chromophores. By adjusting the fluorene and DCMF contents, white light emission could be obtained from a single polymer; a device with an ITO/PEDOT:PSS/polymer/Ca/Al configuration was found to exhibit pure white electroluminescence with Commission Internationale de L'Eclairage (CIE) coordinates of (0.33, 0.31), a maximum brightness of 1180 cd/m², and a current efficiency of 0.60 cd/A. Furthermore, the white light emission of this device was found to be very stable with respect to variation of the driving voltage. The CIE coordinates of the device were (0.32, 0.29), (0.32, 0.29), and (0.33, 0.31) for driving voltages of 7, 8, and 10 V, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3380–3390, 2007     

Synthesis and chiroptical properties of chiral binaphthyl‐containing polyfluorene derivatives

New chiral binaphthyl‐containing polyfluorene (PF) derivatives, PFOH , PFMOM , and PFP , bearing different binaphthyl units ((S)‐2,2′‐bis(methoxymethoxy)‐1,1′‐binaphthyl for PFMOM , (S)‐1,1′‐binaphthyl‐2,2′‐diol for PFOH , and (S)‐2,2′‐bis(diphenylphosphinyl)‐1,1′‐binaphthyl for PFP ) in the backbone have been designed and synthesized through Pd‐catalyzed Suzuki polycondensation. Their properties have been investigated in detail by ¹H NMR, ¹³C NMR, TGA, DSC, UV–vis, photoluminescence (in solutions, in thin films before and after annealing), and circular dichroism (CD) spectroscopic methods compared with poly(9,9‐dihexylfluorene‐2,7‐diyl) ( PF ). The resulting copolymers possessed excellent solubility in organic solvents and emitted strong blue light. The phosphine oxide‐containing copolymers PFP and PFMOM exhibited higher quantum yields and better thermal spectral stability in comparison with PF . All the copolymers exhibited obviously the linearly polarized photoluminescent properties both in solutions and in solid states. High emission polarization ratios (R_PL) of PFP were observed with no obvious decrease upon thermal annealing. In addition, investigation of the CD spectroscopic properties of these copolymers in THF solutions indicated that the chirality of the binaphthyls could be transferred to the whole PF backbone. All these results demonstrated that introduction of the chiral binaphthyls, particularly BINAPO, into the backbone could effectively improve the performances of the copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis,optical properties,and spectral stability of chiral dendronized binaphthyl‐containing polyfluorene derivatives

A new kind of chiral dendronized binaphthyl‐containing random polyfluorene derivatives bearing different contents (3.2–14.9 mol %) of Fréchet's polyether dendritic wedges have been designed and synthesized through a versatile Pd‐catalyzed Suzuki polycondensation. Their properties have been investigated by NMR, TGA, DSC, CD, UV–vis, and photoluminescence and compared to those of poly(9,9‐dihexylfluorene) ( PF ). It was found that attachment of Fréchet's dendritic wedges into the main chain enhanced the emission efficiency and thermal stability of the copolymers. Furthermore, different from PF , good to excellent spectral stabilities in the solid state were proven for all the dendronized chiral copolymers after a thermal annealing under air at 200 °C. The second‐generation dendronized polymer P3 bearing about 15 mol % of dendritic pendants exhibited high quantum yields in both solutions and films, and excellent thermal oxidative stability. These results demonstrated that the combination of the twisted nonplanar binaphthyl and the sterically demanding dendron could efficiently suppress the intermolecular packing and aggregation at much lower dendron contents compared to other reported dendronized polyfluorenes. Additionally, the investigation of circular dichroism spectra of these chiral dendronized polymers showed a strong Cotton effect at long wavelength (378–384 nm), indicating that the chirality of binaphthyl unit was transferred to the whole polyfluorene backbone. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 886–896, 2008     

Terpyridine‐substituted,fluorescent polymers and their chelation with zinc ion: The ligand‐to‐metal ratio and optical properties

Soluble, fluorescent, terpyridine‐substituted, conjugated polymers were prepared and characterized. The polymer chains included a defined oligo(phenylenevinylene) fragment, on which the terpyridine‐functional group was attached. The polymers were blue‐fluorescent with emission peaks at 400–427 nm in tetrahydrofuran solutions. Upon chelation with the Zn(II) cation, the emission maxima were shifted to a longer wavelength by as much as 113 to 506–526 nm. A model compound was also prepared to aid the structural characterization. The ratio of terpyridine to Zn²⁺ in the polymer complex was found to be 1:1 on the basis of spectroscopic evidence, which included mass spectrometry, ¹H NMR, and Job titration. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2338–2345, 2006     

Synthesis,characterization, and electroluminescence of polyfluorene copolymers containing T‐shaped isophorone derivatives

We have successfully synthesized a series of new fluorene‐based copolymers, poly[(9,9‐bis(4‐octyloxy‐phenyl)fluorene‐2,7‐diyl)‐co‐[2(3{2[4(2{4[bis(bromophenyl‐4yl) amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile] (PFTBMs), with varying molar ratios of the low‐energy band gap comonomer, 2(3{2[4(2{4[bis(4‐bromophenyl)amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile (BTBM). To prepare BTBM (which has a T‐shaped structure) from triphenylamine, dialkoxy phenyl, and isophorone, we introduced three individual segments of an isophorone derivative containing two cyanide groups at the carbonyl position, a dialkoxy phenyl group for increased solubility, and a triphenyl amine for effective charge transfer. Furthermore, we introduced vinyl linkages between each segment to increase the length of π‐conjugation. The synthesized polyfluorene copolymers with the BTBM, PFTBMs, were synthesized via palladium‐catalyzed Suzuki coupling reactions. The photoluminescence emission spectra of the synthesized polymers in solution did not show significant energy transfer from PBOPF segments to the BTBM units. Light‐emitting devices based on these polymers were fabricated with an indium tin oxide/poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/polymers/Balq/LiF/Al configuration. Examination of the electroluminescence emission of the synthesized polymers showed that the maximum wavelength shifted continuously toward long wavelengths with as the number of BTBM units in the polymer main chain was increased. In particular, a device using PFTBM 05 exhibited a maximum brightness of 510 cd/m² and a maximum current efficiency of 0.57 cd/A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 82–90, 2010     

Synthesis and characterization of a polyfluorene containing carbazole and oxadiazole dipolar pendent groups and its application to electroluminescent devices

We have synthesized a blue‐light‐emitting polyfluorene (PF) derivative ( PF‐CBZ‐OXD ) that presents bulky hole‐transporting carbazole and electron‐transporting oxadiazole pendent groups functionalized at the C‐9 positions of alternating fluorene units. The results from photoluminescence and electrochemical measurements indicate that both the side chains and the PF main chain retain their own electronic characteristics in the copolymer. An electroluminescent device incorporating this polymer as the emitting layer was turned on at 4.5 V; it exhibited a stable blue emission with a maximum external quantum efficiency of 1.1%. Moreover, we doped PF‐CBZ‐OXD and its analogue PF‐TPA‐OXD with a red‐light‐emitting iridium phosphor for use as components of phosphorescent red‐light emitters to investigate the effect of the host's HOMO energy level on the degree of charge trapping and on the electrophosphorescent efficiency. We found that spectral overlap and individual energy level matching between the host and guest were both crucial features affecting the performance of the electroluminescence devices. Atomic force microscopy measurements indicated that the dipolar nature of PF‐CBZ‐OXD , in contrast to the general nonpolarity of polydialkylfluorenes, provided a stabilizing environment that allowed homogeneous dispersion of the polar iridium triplet dopant. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2925–2937, 2007     

Synthesis and white electroluminescent properties of multicomponent copolymers containing polyfluorene,oligo(phenylenevinylene), and porphyrin derivatives

Two novel multicomponent copolymers ( P1 and P2 ) containing polyfluorene (PF), oligo(phenylenevinylene) ( OPV ), and porphyrin ( Por ) derivatives were synthesized according to the Suzuki polymerization method. The structures, optical, and electrochemical properties of the two model compounds ( OPV and Por ) and multicomponent copolymers were characterized by ¹H NMR, FTIR, elemental analysis, UV–vis spectroscopy, photoluminescence, and cyclic voltammetry, respectively. Both of the copolymers exhibit thermotropic liquid crystalline properties and represent the characteristic Schlieren textures in a wide temperature range. Electroluminescence spectra of these copolymers exhibit broadband emissions covering the entire visible region from 400 to 700 nm. The single layer polymer light emitting diodes device based on P2 with a configuration of indium tin oxide/poly(ethylenedioxythiophene):poly(styrenesulfonic acid)/polymers/Ca/Al emits white light with the Commission Internationale de l′Eclairage chromaticity coordinates of (0.29, 0.30), maximum brightness of 443 cd/m². The white‐light‐emitting devices based on the novel multicomponent copolymers exhibit low turn‐on voltage, and good color stability at different driving voltages as well. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5291–5303, 2009     

Facile electrochemical preparation of poly(9,9‐dichlorofluorene), a new polyfluorene derivative as green light emitter

High‐quality poly(9,9‐dichlorofluorene) (PDCF), a new part soluble polyfluorene derivative, was easily synthesized electrochemically by direct anodic oxidation of 9,9‐dichlorofluorene (DCF) in boron trifluoride diethyl etherate (BFEE) containing 15% (by volume) trifluoroacetic acid (TFA). It was hard for DCF to deposit on the electrode in neutral solvents such as CH₃CN system. This methodology may help promotion of researches to reveal unknown properties and applications of polyfluorene materials. PDCF films with conductivity of 3.3 × 10^?2 S cm^?1 obtained from this media show good redox activity and thermal stability. The structure and morphology of the polymer were studied by UV–vis, FTIR, ¹H NMR spectra, and scanning electron microscopy, respectively. The results of quantum chemistry calculations and the spectroscopies of dedoped PDCF indicate that the polymerization of DCF mainly occurs via C₍₂₎ and C₍₇₎ position. Fluorescent spectral studies indicate that PDCF film with high fluorescence quantum yields and photochemical stability is a novel green light emitter. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1791–1799, 2010     

Triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands as chemosensors for metal ions

Two well‐defined triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands were synthesized through Suzuki coupling polymerization and were further characterized by ¹H‐NMR, ¹³C‐NMR, gel permeation chromatography, Infrared, and UV‐vis spectra. Polymer P‐1 , terpyridine‐bearing poly(triphenylamine‐alt‐fluorene) with a high fluorescence quantum yield (62%) shows much higher sensitivities toward Fe³⁺, Ni²⁺, and Cu²⁺ as compared with the other metal ions investigated. Especially, Fe³⁺ can lead to an almost complete fluorescence quenching of polymer P‐1 . Whereas, the analogous polymer P‐2 , in which N‐ethylcarbazole repeat units replace the fluorene units in P‐1 , shows a very poor selectivity. It demonstrates that polymers with a same receptor may show different sensitivity to analytes owing to their different type of backbones. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1310–1316, 2010     

Cyclometalated Pt complex based random terpolymers as electron acceptors for all polymer solar cells

Various molar ratios of platinum complexes were introduced into the conjugated backbone of the well‐studied poly[[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)](PNDIT2) acceptor polymer through random terpolymer approach. Terpolymers PNDIT2Ptx (x = 1, 2 and 5) exhibited slightly higher melting point (T_m), crystallization temperature, HOMO and LUMO energy levels than the control PNDIT2 copolymer due to the introduction of small amount of weaker electron‐withdrawing bulky rigid Pt complex instead of strong electron‐withdrawing flexible naphthalene diimide. When blended them with poly[[2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b] dithiophene] [3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]] (PTB7‐Th) in all polymer solar cells, enhanced power conversion efficiency of 4.51% (3.74%) was obtained in terpolymer PNDIT2Pt1 based device compared to 3.88% (3.24%) of the control PNDIT2 at the same inverted (conventional) device conditions. The enhancement was probably ascribed to higher hole and electron transport ability and more efficient charge separation. To the best of our knowledge, this is the first example of random terpolymer acceptors based on heavy metal complexes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 105–115     

Synthesis of π‐conjugated polymer containing both thiophene and phosphole sulfide in the main chain by simultaneous post‐element transformation of organotitanium polymer

The synthesis and unique optoelectronic features of a π‐conjugated polymer containing both thiophene and 1‐phenylphosphole sulfide units (multiple heteroles) in the main chain by the post‐element transformation of a regioregular organometallic polymer possessing titanacyclopentadiene‐2,5‐diyl unit are described. The π‐conjugated polymer containing multiple heteroles was obtained in 73% yield by the simultaneous reaction of the organotitanium polymer with sulfur monochloride and dichlorophenylphosphine (0.6 equiv each), whose number‐average molecular weight (M_n) and the molecular‐weight distribution (M_w/M_n) were estimated to be 11,000 and 3.4, respectively, by the size exclusion chromatography (SEC). The π‐conjugated polymer thus obtained was found to have the high HOMO and the low LUMO energy levels due to the electron‐rich thiophene and electron‐deficient phosphole sulfide units, respectively, as supported by its cyclic voltammetry (CV) analysis. Compared to a mixture of a polymer containing sole thiophene‐unit and that containing sole phosphole sulfide units, the π‐conjugated polymer‐containing multiple heteroles proved to exhibit interesting optical properties. For example, a specific emission peak was observed at 608 nm in the photoluminescence spectrum, which was not observed in the case of the thiophene‐containing polymer, the phosphole‐containing polymer, and their mixture. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2519–2525     

Synthesis of new polyfluorene copolymers with a comonomer containing triphenylamine units and their applications in white‐light‐emitting diodes

Novel conjugated polyfluorene copolymers, poly[9,9‐dihexylfluorene‐2,7‐diyl‐co‐(2,5‐bis(4′‐diphenylaminostyryl)‐phenylene‐1,4‐diyl)]s (PGs), have been synthesized by nickel(0)‐mediated polymerization from 2,7‐dibromo‐9,9‐dihexylfluorene and 1,4′‐dibromo‐2,5‐bis(4‐diphenylaminostyryl)benzene with various molar ratios of the monomers. Because of the incorporation of triphenylamine (TPA) moieties, PGs exhibit much higher HOMO levels than the corresponding polyfluorene homopolymers and are able to facilitate hole injection into the polymer layer from the anode electrode in light‐emitting diodes. Conventional polymeric light‐emitting devices with the configuration ITO/PEDOT:PSS/polymer/Ca/Al have been fabricated. A light‐emitting device produced with one of the PG copolymers (PG10) as the emitting layer exhibited a voltage‐independent and stable bluish‐green emission with color coordinates of (0.22, 0.42) at 5 V. The maximum brightness and current efficiency of the PG10 device were 3370 cd/m² (at 9.6 V) and 0.6 cd/A, respectively. To realize a white polymeric light‐emitting diode, PG10 as the host material was blended with 1.0 wt % of a red‐light‐emitting polymer, poly[9,9‐dioctylfluorene‐2,7‐diyl‐alt‐2,5‐bis(2‐thienyl‐2‐cyanovinyl)‐1‐(2′‐ethylhexyloxy)‐4‐methoxybenzene‐5′,5′‐diyl] (PFR4‐S), and poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV). The device based on PG10:PFR4‐S showed an almost perfect pure white electroluminescence emission, with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.36) at 8 V; for the PG10:MEH‐PPV device, the CIE coordinates at this voltage were (0.30, 0.40) with a maximum brightness of 1930 cd/m². Moreover, the white‐light emission from the PG10:PFR4‐S device was stable even at different driving voltages and had CIE coordinates of (0.34, 0.36) at 6 V and (0.31, 0.35) at 10 V. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1199–1209, 2007     

Synthesis and characterization of fluorene‐based copolymers containing benzothiadiazole derivative for light‐emitting diodes applications

Five new thermally robust electroluminescent fluorene‐based conjugated copolymers, including poly[2,7‐(9,9‐dioctylfluorene)‐co‐4,7‐{5,6‐bis(3,7‐dimethyloctyloxymethyl)‐2,1,3‐(benzothiadiazole)}] ( PFO‐P2C₁₀BT ) were synthesized and used to fabricate the efficient polymer light‐emitting diodes (PLEDs). The glass transition temperatures of the polymers were found to be higher than that of poly(9,9‐dialkylfluorenes) and are in the range 113–165 °C. We fabricated PLEDs in indium‐tin oxide/PEDOT/light‐emitting polymer/cathode configurations using either double‐layer LiF/Al or triple‐layer Alq₃/LiF/Al cathode structures. The new copolymers were found to have emission colors that vary from greenish blue (491 nm) to green (543 nm) depending on the copolymer composition. The maximum brightness and luminance efficiency of these PLEDs were found to be up to 5347 cd/m² and 1.51 cd/A at 10 V, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6762–6769, 2008     

Photovoltaic properties of the polymer solar cells comprising crosslinked maleimide polymers and fullerene‐derivative PCBM

A series of crosslinkable maleimide conjugated polymers with different vinyl group contents as side‐chain crosslinking sites have been synthesized by the Suzuki coupling reaction. Polymer solar cells (PSCs) were fabricated based on an interpenetrating network of the crosslinkable maleimide polymers as the electron donor, and a fullerene derivative, (6,6)‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM), as the electron acceptor. The crosslinkable maleimide polymers underwent crosslinking reaction at the side‐chain vinyl groups upon the thermal treatment with or without the addition of initiator, azobisisobutyronitrile (AIBN). Better photovoltaic (PV) performances were obtained for the PSCs based on the polymer crosslinking without using initiator, whereas poorer PV performances were observed for the PSCs based on the polymer crosslinking with the AIBN initiator. In addition, higher operational stability was observed for the crosslinked polymer based solar cell as compared to the solar cell based on the un‐crosslinked polymer. The photo‐physical and PV properties of the cross‐linked maleimide polymers/PCBM based PSCs are discussed in detail as the morphology and crosslinking density of the polymers are taken into account. Copyright © 2010 John Wiley & Sons, Ltd.     

Amphiphilic dendritic copolymers of tert‐butyl‐glycidylether and glycidol as a nanocontainer for an anticancer ruthenium complex

Dendritic copolymers comprising a hydrophobic core and hydrophilic shell with nearly equal numbers of hydroxyl groups in the shell and different densities in the core were prepared by a multi‐step process based on anionic ring‐opening polymerization. The diversity in the core density was obtained by using copolymer stars with poly(tert‐butyl‐glycidylether)‐block‐polyglycidol arms with nearly equal length of hydrophobic blocks and numbers of hydroxyl groups of polyglycidol but different numbers of arms as macroinitiators. The ability of the dendritic copolymers to serve as a nanocontainer for a ruthenium complex Ru(NH₃)₃Cl₃ with anticancer properties was studied. The possibility of improving the water solubility of this poorly soluble drug by loading it onto dendritic copolymers was investigated. The hydroxyl groups of the dendritic copolymers were used for complexation of the ruthenium compound to the shell. The loading efficiency was analyzed by UV–vis spectroscopy. The dendritic nanoparticles in their hydrated state were visualized using cryo‐TEM. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3488–3497     

Optical properties of a novel fluorene‐based thermally stable conjugated polymer containing pyridine and unsymmetric carbazole groups

A new diiodo monomer containing heterocyclic pyridine and carbazole groups was synthesized via Chichibabin reaction and used in the preparation of a conjugated polymer via Suzuki coupling approach. The conjugated polymer was highly soluble in common organic solvents such as NMP, THF, dichloromethane, chloroform, toluene, xylene, and benzene at room temperature. The polymer had high glass transition temperature at 191 °C and T_d10 at 434 °C in nitrogen atmosphere. The pristine polymer exhibited the UV–vis maximum absorption at 355 nm and shifted to 420 nm after protonation. The emission of the polymer in THF solution changed from the blue region with maximum peak at 400 nm to the yellow region with maximum peak at 540 nm after protonated by HCl, and the intensity of emission depended on the concentration of acid. The polymer also showed electrochromic behavior under applied voltage. The emission color of the polymer film changed from blue (435 nm) to yellow (570 nm) when 2.5 V bias voltage was applied. The polymer also exhibited write‐once and read‐many‐times (WORM) polymer memory effect with tristable states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 991–1002, 2009     

Direct measurement of the end-to-end distance of individual polyfluorene polymer chains.

Wide-field imaging of individual multichromophoric molecules and successive photobleaching were used to determine, accurately, the relative position of the chromophores in such systems. First, a polyphenylene dendrimer with well-defined geometry was used to establish the accuracy in localization that can be obtained by this methodology. For a signal-to-noise ratio of 20, interchromophoric distances could be measured with 4 nm accuracy. Next, the method was used to determine the end-to-end distribution of an end-capped polyfluorene polymer. From comparison between the experimental and simulated distributions, information on the conformation of the polymer could be deduced. It was found that the polymer has a nonlinear conformation. A conjugation length of six monomer units gave the best fit of the experimental data to the proposed model.     

Synthesis and properties of polythiophene derivatives containing triphenylamine moiety and their photovoltaic applications

A series of novel soluble polythiophene derivatives containing triphenylamine moiety were synthesized by Grignard metathesis (GRIM) method. The structures of the polymers were characterized and their physical properties were investigated. High molecular weight (M_n up to 25,800 g/mol) and thermostable polymers were obtained. The absorption spectra demonstrated that the absorption wavelength of the polymers could be tuned dramatically by introducing thiophene units in the main chain of the polymers. Photoluminescence spectra indicated that there was intramolecular energy transfer from the side chain to the main chain, and the maximum emission was red‐shifted gradually with the increase of thiophene units in the main chain. Cyclic voltammetry displayed that the polymers possessed relatively high oxidation potential, which promised good air stability and high open circuit voltage for photovoltaic cells application. Finally, bulk heterojunction photovoltaic devices were fabricated by using the polymers as donors and (6,6)‐phenyl C₆₁‐butyric acid methyl ester (PCBM) as acceptor. The maximal open circuit voltage of the photovoltaic cells reached 0.71–0.87 V and the power conversion efficiencies of the devices were measured between 0.014% and 0.45% under white light at 100 mW/cm². © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3970–3984, 2008     

（C_5H_5）_3Nd（THF）的晶体结构

报导了一种新型（Ｃ_５Ｈ_５）３Ｎｄ（ＴＨＦ）晶体结构，晶体属单斜晶系，Ｃ２／ｃ空间群，晶胞参数为ａ＝１２．８３９（７），ｂ＝１０．５２０（３），ｃ＝２６．５９９（９），β＝９８．５０°，Ｖ＝３５５３（３），Ｚ＝８，Ｄ_ｃ＝１．５４ｇ／ｃｍ￣３，Ｍ_ｒ＝４１１．６３，μ＝２９．２９ｃｍ（－１），Ｆ（０００）＝１６４０，最终偏离因子为Ｒ＝０．０６１，Ｒｗ＝０．０７３。新晶体结构在空间群、晶胞参数和Ｚ值上均明显不同于前面的报导，在Ｃｐ３Ｌｎ·ＴＨＦ系列化合物中，这是首次发现同一化合物可以用两种分子堆积方式结晶。