Influence of Side‐Chain Composition on Polythiophene Properties and Supramolecular Assembly of Anionic Polythiophene Derivatives

A series of 10 polythiophene derivatives is reported, in which each polymer has a different percentage of carboxylic acid‐bearing repeat units. The properties of these polymers are explored under acidic conditions, where the carboxylic acid moieties remain neutral, and under basic conditions, where the carboxylic acid units become anionic carboxylates. The properties that are examined for both solutions and films include UV–vis absorption spectroscopy, photoluminescence spectroscopy, and red‐edge optical band gaps. All the properties studied are strongly dependent both on protonation state and percentage of carboxylic acid/carboxylate side chains along the polymer backbone. The anionic form of each polythiophene derivative was also used in layer‐by‐layer film deposition with a cationic phosphonium polyelectrolyte. The film growth process was studied by spectroscopic techniques to assess the influence of side‐chain composition on the film growth and optical properties. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019     

Photoactive Polythiophene:Titania Hybrids with Excellent Miscibility for Use in Polymer Photovoltaic Cells

A series of poly{(3‐hexylthiophene)‐co‐[3‐(6‐hydroxyhexyl)thiophene]}:titania (P3HT‐OH:TiO₂) hybrids were synthesized via the in situ polycondensation of titanium (IV) n‐butoxide in the presence of P3HT‐OH. Introducing a hydroxyl moiety onto the side‐chain of poly(3‐hexylthiophene) (P3HT) significantly promotes the polymer‐titania interaction, resulting in the formation of homogeneous hybrid colloids. The UV‐vis spectra of P3HT‐OH:TiO₂ films demonstrate that TiO₂ markedly affects the stacking structure and the chain conformation of P3HT‐OH. The maximum absorption wavelength of these hybrid materials can be tailor‐made by merely varying the weight percentage of TiO₂. Moreover, P3HT‐OH:TiO₂ can be further utilized as an efficient compatibilizer in preparing photoactive P3HT:P3HT‐OH:TiO₂ films with excellent miscibility. The photovoltaic cell based on such a hybrid exhibited a 2.4‐fold higher value of power‐conversion efficiency compared to the cell based on P3HT:TiO₂.

     

Synthesis and Photovoltaic Properties of Polythiophene Incorporating with 3,4-Difluorothiophene Units

Two polythiophene derivatives using fluorine atoms and hexyl or hexyloxy group as electron-withdrawing and donating substituents have been synthesized. The introduction of fluorine atoms to the polythiophene backbones simultaneously lowers the HOMO and narrows the bandgap, and the stronger electron-donating ability of hexyloxy side chain further reduces the bandgap. As a result, poly[3-hexylthiophene-2,5-diyl-alt-3,4-difluorothiophene] （PHTDFT） shows HOMO and bandgap of -5.31/1.83 eV and poly[3,4-dihexyloxythiophene-2,5-diyl-alt-3,4-di- fluorothiophene] （PDHOTDFT） shows HOMO and bandgap of -5.14/1.68 eV, both are lower than --4.76/2.02 eV of P3HT. Benefiting from the lower HOMO, PHTDFT：PC61BM （1 ＂ 1） polymer solar cells obtain a power conversion efficiency of 1.11% and an impressed open-circuit voltage of 0.79 V under solar illumination AM1.5 （100 mW/cm2）.     

一维取代聚噻吩的电子性能

报道了3种取代聚噻吩,3-己基聚噻吩(P3HT)、3,4-二戊基聚噻吩(P34PT)、3-辛氧基聚噻吩(P3OOT)的合成方法1、H-NMR测试结果及UV-Vis吸收光谱和荧光光谱分析结果。用密度泛函方法计算了无取代噻吩、3-乙基噻吩、3,4-二乙基噻吩、3-乙氧基噻吩二聚体的电子性能。随聚合度的提高,聚合物能隙变窄。无取代噻吩二聚体的能隙为4.216 eV,重复单元长度为0.392 7 nm;乙基取代噻吩二聚体的能隙为4.733 eV,重复单元长度为0.393 9 nm;乙氧基取代噻吩二聚体的能隙为3.890 eV,重复单元长度为0.390 8 nm;双乙基取代噻吩二聚体的能隙为5.168 eV,重复单元长度为0.392 5 nm。理论变化规律与实验结果基本一致。     

聚噻吩的固相聚合及其应用

作为共轭聚合物的典型代表,因聚噻吩衍生物具有良好的稳定性和结构易改性,其在有机光电子领域、新能源等有重要的应用。而固相聚合作为一种环保、可大规模制备等优点,受到研究者的关注。本文主要总结了近年来聚噻吩及其衍生物的固相聚合反应单体分子设计、聚合研究机理以及相关应用的进展,并展望了未来的研究方向。     

Synthesis and characterization of polythiophene derivatives with nitrogen heterocycles on the side chain

The Grignard metathesis reaction of 2,5‐dibromo‐3‐(5′‐hexylpyridine‐2′‐yl)thiophene ( M1 ) with i‐PrMgCl afforded 5‐bromo‐2‐chloromagnesio‐3‐(5′‐hexylpyridine‐2′‐yl)thiophene ( GM1 ) in the 86% selectivity. The Kumada coupling polymerization by Ni(dppp)Cl₂ gave poly M1 having the roughly controlled molecular weight between 6700 and 23,400. The characterization using the gel permeation chromatographic and matrix‐assisted laser desorption/ionization‐time of flight mass spectra indicated the diffusion of the nickel catalyst from the propagating end. Based on the GC and ¹H NMR spectra, the head‐to‐tail content of poly M1 was calculated to be 89%. The regioselective Grignard metathesis reactions of 5,5′‐dibromo‐4‐(5″‐hexylpyridine‐2″‐yl)‐2,2′‐bithiophene ( M2 ) and 5,5′‐dibromo‐4‐(5″‐hexylpyrimidine‐2″‐yl)‐2,2′‐bithiophene ( M3 ) also occurred at the ortho‐position of the nitrogen heterocycle. The Kumada coupling polymerizations gave poly M2 and poly M3 having the head‐to‐tail content of 75% and 85%, respectively. The UV–vis spectra of polymers suggested that the polymer conformation becomes more planar in the order of poly M1 < poly M3 < poly M2 , which was investigated by the theoretical calculation of the model oligomers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2166–2174     

聚噻吩/多壁碳纳米管复合材料结构与导电机理的研究

从结构和相互作用方面对聚噻吩(PTh)/多壁碳纳米管(MWNTs)复合材料进行了研究, 结果表明: 一方面聚噻吩本身的结构对其导电性能有一定的影响, 另一方面MWNTs作为一种掺杂剂, 和聚噻吩之间存在强的相互作用, 电子从MWNTs转移到聚噻吩. MWNTs和它周围被掺杂的聚噻吩通过π-π共轭作用形成相对独立的导电单元, 在复合材料的导电体系中起到主要作用, 随着这种导电单元数量的增加直至相互接触, 形成大的导电体系, 复合材料的电导率达到最大值.     

A Self‐Assembling Polythiophene Functionalised with a Cysteine Moiety

A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal‐ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N‐(tert‐butoxycarbonyl)‐S‐thien‐3‐ylcysteinate and distannylthiophene through a Stille coupling reaction. UV‐vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self‐assembling structures, through the formation of a hydrogen‐bond network, not only in the solid state but also in solution.

     

Biomimetic Networks with Enhanced Photodynamic Antimicrobial Activity from Conjugated Polythiophene/Polyisocyanide Hybrid Hydrogels

Hybrid biomimetic hydrogels with enhanced reactive oxygen species (ROS)‐generation efficiency under 600 nm light show high antibacterial activity. The hybrid gels are composed of helical tri(ethylene glycol)‐functionalized polyisocyanides (PICs) and a conformation‐sensitive conjugated polythiophene, poly(3‐(3′‐N,N,N‐triethylammonium‐1′‐propyloxy)‐4‐methyl‐2,5‐thiophene chloride) (PMNT). The PIC polymer serves as a scaffold to trap and align the PMNT backbone into a highly ordered conformation, resulting in redshifted, new sharp bands in the absorption and fluorescence spectra. Similar to PIC, the hybrid closely mimics the mechanical properties of biological gels, such as collagen and fibrin, including the strain stiffening properties at low stresses. Moreover, the PMNT/PIC hybrids show much higher ROS production efficiency under red light than PMNT only, leading to an efficient photodynamic antimicrobial effect towards various pathogenic bacteria.     

低聚噻吩衍生物单体的合成及其聚合物薄膜的电致变色性能

合成了两种低聚噻吩衍生物单体:2,3':4',2'-三噻吩(I3T)和5,5'-二醛基-2,3':4',2'-三噻吩(OHC-I3T-CHO).通过电化学方法对单体I3T和OHC-I3T-CHO进行了聚合,制备了相应的聚噻吩衍生物.研究了聚噻吩衍生物薄膜的电致变色性能.当外加一定电压时,基于单体I3T的聚噻吩衍生物薄膜可以在淡黄色和淡蓝色之间发生可逆的颜色变化,基于单体OHC-I3T-CHO的聚噻吩衍生物薄膜能在红色和墨绿色间发生可逆的颜色变化.     

Novel Cross‐Linked Conducting Polythiophene with Yellow‐Green‐Light‐Emitting Properties and Good Thermal Stability

A novel conjugated polythiophene derivative with polymethacrylate attaching to the polymer backbone via an alkyl spacer was successfully synthesized. A methacrylate‐substituted thiophene monomer, 3‐(hexyl methacrylate)thiophene was prepared and polymerized by free radical polymerization, followed by an electrochemical polymerization. The resulting polymer as a yellow‐green‐light emitter, has potential applications in photoelectronics area.     

Linking Polythiophene Chains Through Conjugated Bridges: A Way to Improve Charge Transport in Polymer Solar Cells

Summary: A series of cross‐linked polythiophene derivatives ( P1 – 4 ) are synthesized by adding different ratio (0, 2, 5, and 10%) of conjugated cross‐linker via a Stille coupling reaction. From P1 – 4 , with the increase of the content of the conjugated bridges, the UV‐visible absorption peaks of the polymers were shifted towards blue and their electrochemical bandgap increased. The hole mobilities of P1 – 4 as determined from the SCLC model are 5.23 × 10⁻⁶, 1.28 × 10⁻⁴, 7.01 × 10⁻³, and 2.34 × 10⁻⁵ cm² · V⁻¹ · s⁻¹, respectively. The PCEs of the polymer solar cells based on P1 – 4 are 0.37, 1.05, 1.26, and 0.78%, respectively. The improvement of PCE of the devices based on P2 – 4 compared with that of P1 may be due to the increase of hole mobility.

Molecular structure of the polythiophene derivatives ( P1 – 4 ).     

Aggregation of polythiophene homopolymer and block copolymer in solution utilizing the characteristics of pyridine at the side chain

Poly[3‐(5′‐hexylpyridine‐2′‐yl)thiophene] ( P3PT ) (M_n = 13900, H‐T content = 90%) was prepared by the regioselective Grignard metathesis reaction and the subsequent Kumada coupling polymerization. Likewise, poly(3‐hexylthiophene)‐b‐poly[3‐(5′‐hexylpyridine‐2′‐yl)thiophene] ( P3HT‐b‐P3PT ) (M_n = 17,300) was synthesized in the one‐pot and successive monomer addition protocol, in which the segment ratio was calculated to be 56 ( P3HT )/44 ( P3PT ) base on the ¹H NMR spectrum. The absorption and emission spectra of homopolymer P3PT(H) , obtained by the protonation of the pyridine nitrogen, in THF/cyclohexane shifted to the longer wavelength as compared with those collected in THF, suggesting the aggregation in poor solvent. The aggregation of P3PT induced by the addition of Sc(OTf)₃ could be controlled by the molar ratio of pyridine and scandium complex. The protonated block copolymer P3HT‐b‐P3PT(H) was also subjected to the aggregate formation. The absorption maximum in THF/CH₃OH showed a bathochromic shift and the fluorescence emission was almost quenched. From the ¹H NMR spectra and DLS measurements, P3HT‐b‐P3PT(H) forms nanometer scale aggregates particularly with the insolubility and stacking of non‐ionic P3HT in alcohol as the driving force. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3383–3389     

Polythiophenes bearing electron‐withdrawing groups in the side chain and their application to bulk heterojunction solar cells

Soluble polythiophenes bearing strong electron withdrawing groups, dicyanoethenyl [? CH?C(CN)₂] (PTDCN) and cyano‐methoxycarbonylethenyl [? CH?C(CO₂Me)CN] (PTCNME), in the side chains have been prepared. Optical band gaps calculated from onset absorption were 1.70 eV and 1.73 eV for PTDCN and PTCNME, respectively. Highest occupied molecular orbital energy levels measured with a surface analyzer (AC‐2) were ?5.53 eV and ?5.29 eV for PTDCN and PTCNME, respectively, which were much lower than that of poly(3‐hexylthiophene) (?4.81 eV). To investigate photovoltaic properties, bulk heterojunction polymer solar cells based on PTDCN and PTCNME were fabricated with a structure of ITO/PEDOT:PSS/active layer/LiF/Al, where the active layer was a blend film of polymer and [6,6]‐phenyl C₆₁ butyric acid hexyl ester (PC₆₁BH). Solar cell parameters were estimated from current density–voltage (J–V) characteristics under the illumination of AM1.5 at 100 mW/cm². The solar cell based on the blend film of PTCNME:PC₆₁BH (1:1) showed power conversion efficiency (PCE) of 0.72% together with the open current voltage (V_oc) of 0.61 V, the short current density (J_sc) of 3.90 mA/cm², and the fill factor of 30.3%. The PCE of a solar cell fabricated from PTDCN in a similar way was 0.56%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

聚噻吩制备条件对其结构和导电性能的影响

通过改变聚噻吩合成条件(温度、浓度、反应时间)得到各种不同样品, 用FESEM, FTIR光谱, Raman光谱, XRD, UV-Vis光谱和TG等手段对样品进行研究. 结果表明, 不同的制备条件会影响噻吩环的连接方式, 直接影响聚噻吩结构的分布. 导电性能研究表明, 聚噻吩的结构差异和其导电性能直接相关, 实验证明以α-α相连接的聚噻吩有更高的电导率.     

High performance polymer field‐effect transistors based on polythiophene derivative with conjugated side chain

Poly(3‐[2‐(5‐hexyl‐2‐thienyl) ethenyl]‐2,2′‐bithiophene) ( P2 , see Scheme 1 ) with conjugated thienylvinyl side chain was synthesized by copolymerization of the thiophene units with and without conjugated side chain with Pd‐catalyzed Stille coupling method. For comparison, P1 with the hexyl side chain instead of conjugated side chain was also synthesized. P2 film shows broad absorption in the visible region with absorption edge at about 700 nm. The solution‐processed polymer field‐effect transistors were fabricated and characterized with bottom gate/top contact geometry. The organic field‐effect transistors (OFET) based on P2 showed an average hole mobility of about 0.034 cm²/Vs (the highest value reached 0.061 cm²/Vs) upon annealing at about 180 °C for 30 min, with a threshold voltage of ?1.15 V and an on/off ratio of 10⁴ with n‐octadecyltrichlorosilane (OTS) modified SiO₂ substrate. In comparison, the OFET based on P1 displayed a hole mobility of 8.9 × 10^–4 cm²/Vs and an on/off ratio of 10⁴ with OTS modified SiO₂ substrate. The results indicate that the polythiophene derivative with conjugated thienylvinyl side chain is a promising polymer for the application in polymer field‐effect transistors. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5304–5312, 2009     

光诱导聚合制备聚噻吩/二氧化钛复合粒子的结构及光催化性能

通过光诱导噻吩在TiO2的氯仿悬浮液中聚合反应,制备了聚噻吩/二氧化钛(PTh/TiO2)复合粒子,并采用比表面积分析仪、扫描电子显微镜、粒径分析仪、X射线光电子能谱、紫外-可见漫反射光谱和红外光谱对复合粒子进行了表征.结果表明,PTh/TiO2复合粒子上的聚噻吩骨架中S原子与TiO2粒子间存在强相互作用,该复合粒子对...     

Preparation,Characterization and Electromagnetic Shielding Effectiveness of Conductive Polythiophene/Poly(ethylene terephthalate) Composite Fibers

Conductive polythiophene (PTh)/poly(ethylene terephthalate) (PET) composite fibers were prepared by polymerization of thiophene in the presence of PET fibers in acetonitrile medium using FeCl₃. The effects of polymerization conditions such as oxidant/monomer mol ratio and polymerization temperature and time on PTh content and surface electrical resistivity of PTh/PET composite fiber were investigated in detail. It was observed that the usage of preswelled PET fibers in dichloromethane increased the PTh content and decreased surface resistivity of composite fiber. Composite fiber having the highest PTh content (5.7%) and the lowest surface resistivity (80 kΩ) was obtained at 20°C with 1.25 M FeCl₃ and 0.42 M thiophene concentrations. The washing effects of laundering detergent and dry cleaning liquid on surface resistivity of composite fibers were investigated. The electromagnetic shielding effectiveness (EMSE) and relative shielding efficiency by absorption and reflection of composite fibers were measured in the radio and microwave frequency range. The results show that the EMSE values decreased with increasing frequency from radio waves to microwaves with an attenuation of 21 dB to 4 dB.