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4208 KiB

Open AccessArticle

Wide Band Gap Polymer Based on Indacenodithiophene and Acenaphthoquinoxaline for Efficient Polymer Solar Cells Application

by Ming Liu, Zhitian Liu, Yong Zhang and Liancheng Zhao

Polymers 2017, 9(11), 578; https://doi.org/10.3390/polym9110578 - 7 Nov 2017

Cited by 10 | Viewed by 6215

Abstract

A new wide band gap polymer PIDT-AQx with indacenodithiophene (IDT) as the electron-rich unit and acenaphthoquinoxaline (AQx) as the electron-deficient unit has been designed and synthesized. The optical band gap of PIDT-AQx was 1.81 eV with a HOMO energy level of −5.13 eV. [...] Read more.

A new wide band gap polymer PIDT-AQx with indacenodithiophene (IDT) as the electron-rich unit and acenaphthoquinoxaline (AQx) as the electron-deficient unit has been designed and synthesized. The optical band gap of PIDT-AQx was 1.81 eV with a HOMO energy level of −5.13 eV. Polymer solar cells with the blend of PIDT-AQx/PC₇₁BM as the active layer achieved a power conversion efficiency (PCE) of 4.56%, with an open-circuit voltage (V_oc) of 0.84 V, a current density (J_sc) of 9.88 mA cm⁻², and a fill factor (FF) of 55% without any solvent additives and pre- or post-treatments. The photovoltaic performance of PIDT-AQx could be slightly improved with a PCE up to 4.78% after thermal annealing due to enhanced J_sc. The results indicate that acenaphthoquinoxaline is a promising building block for developing conjugated polymers for efficient solar cells application. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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4148 KiB

Open AccessArticle

Conjugated Polymers Containing BODIPY and Fluorene Units for Sensitive Detection of CN⁻ Ions: Site-Selective Synthesis, Photo-Physical and Electrochemical Properties

by Tian He, Danting Tang, Cuiling Lin, Xi Shen, Chenjie Lu, Luonan Xu, Zhengye Gu, Zheng Xu, Huayu Qiu, Qian Zhang and Shouchun Yin

Polymers 2017, 9(10), 512; https://doi.org/10.3390/polym9100512 - 14 Oct 2017

Cited by 19 | Viewed by 6905

Abstract

Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) have been designed and [...] Read more.

Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached to the 3,5- or 2,6-positions of BODIPY by ethynylenes or p-diacetylenebenzene. The obtained polymers show good thermal stability and broad absorption in the wavelength range from 300 to 750 nm. The effects of site-selective copolymerization and conjugation length along the polymer backbone on the optoelectronic and electrochemical properties of these copolymers were systematically studied by UV-Vis spectroscopy, photoluminescence (PL) and cyclic voltammetry. Besides, it is found that the BODIPY-based copolymers exhibit selectively sensitive responses to cyanide anions, resulting in obvious change of UV-Vis absorption spectra and significant fluorescence quenching of the polymers among various common anions. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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8028 KiB

Open AccessArticle

Nitrogen Doped Macroporous Carbon as Electrode Materials for High Capacity of Supercapacitor

by Yudong Li, Xianzhu Xu, Yanzhen He, Yanqiu Jiang and Kaifeng Lin

Polymers 2017, 9(1), 2; https://doi.org/10.3390/polym9010002 - 13 Jan 2017

Cited by 31 | Viewed by 8642

Abstract

Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC) with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act [...] Read more.

Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC) with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act as electrode materials in supercapacitors. By the nice carbonized process, i.e., pre-carbonization at 400 °C and then pyrolysis at 700/800/900/1000 °C, NMC replicas with high BET specific surface areas exhibit excellent stability and recyclability as well as superb capacitance behavior (~413 F

\cdot

g⁻¹) in alkaline electrolyte. This research may provide a method to synthesize macroporous materials with continuous channels and hierarchical pores to enhance the infiltration and mass transfer not only used as electrode, but also as catalyst somewhere micro- or mesopores do not work well. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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2416 KiB

Open AccessArticle

Gamma-Irradiation Effects on the Spectral and Amplified Spontaneous Emission (ASE) Properties of Conjugated Polymers in Solution

by Mohamad S. AlSalhi, Saradh Prasad, D. Devaraj and Ziad S. Abo Mustafa

Polymers 2017, 9(1), 7; https://doi.org/10.3390/polym9010007 - 28 Dec 2016

Cited by 4 | Viewed by 5650

Abstract

In this paper, we investigate the effects of gamma (γ) radiation on the spectral and mplified spontaneous emission (ASE) properties of two conjugated polymers (CPs) viz., poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH–PPV) (CPM) and poly{[2-[2′,5′-bis(2″-ethylhexyloxy)phenyl]-1,4-phenylenevinylene]-co-[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene]} (BEHP-co-MEH–PPV) (BMP) in tetrahydrofuran [...] Read more.

In this paper, we investigate the effects of gamma (γ) radiation on the spectral and mplified spontaneous emission (ASE) properties of two conjugated polymers (CPs) viz., poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH–PPV) (CPM) and poly{[2-[2′,5′-bis(2″-ethylhexyloxy)phenyl]-1,4-phenylenevinylene]-co-[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene]} (BEHP-co-MEH–PPV) (BMP) in tetrahydrofuran (THF). Gamma irradiation strongly affected the photophysical properties of these CPs. To explore these changes, gamma radiation, in the range of 2–50 kGy, was used to maintain the temperature at 5 °C constant for all doses at a dose rate of 12.67 kGy/h, using a ⁶⁰Co gamma ray. The ASE profiles of the CPs in THF were obtained under the high power excitation of a Nd:YAG laser (355 nm), pre- and post-radiation. The result revealed a dramatic blue shift of the fluorescence and the ASE spectra after gamma irradiation. This shift in the luminescence and ASE spectra could be a response to the conformational disorders such as gamma irradiation-induced polymer crosslinking, which was verified using Raman spectra, FTIR, and swelling experiments. This could be the first report on the effect of gamma radiation on the ASE properties of conjugated polymers. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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4488 KiB

Open AccessArticle

Intrinsic Delocalization during the Decay of Excitons in Polymeric Solar Cells

by Weikang Chen, Deyao Jiang, Renai Chen, Sheng Li and Thomas F. George

Polymers 2016, 8(12), 414; https://doi.org/10.3390/polym8120414 - 30 Nov 2016

Viewed by 4985

Abstract

In bulk heterojunction polymer solar cells, external photoexcitation results in localized excitons in the polymer chain. After hot exciton formation and subsequent relaxation, the dipole moment drives the electron to partially transfer to extended orbitals from the original localized ones, leading to self-delocalization. [...] Read more.

In bulk heterojunction polymer solar cells, external photoexcitation results in localized excitons in the polymer chain. After hot exciton formation and subsequent relaxation, the dipole moment drives the electron to partially transfer to extended orbitals from the original localized ones, leading to self-delocalization. Based on the dynamic fluorescence spectra, the delocalization of excitons is revealed to be an intrinsic property dominated by exciton decay, acting as a bridge for the exciton to diffuse in the polymeric solar cell. The modification of the dipole moment enhances the efficiency of polymer solar cells. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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2210 KiB

Open AccessArticle

Core/Shell Conjugated Polymer/Quantum Dot Composite Nanofibers through Orthogonal Non-Covalent Interactions

by Brad W. Watson, Lingyao Meng, Chris Fetrow and Yang Qin

Polymers 2016, 8(12), 408; https://doi.org/10.3390/polym8120408 - 24 Nov 2016

Cited by 15 | Viewed by 6448

Abstract

Nanostructuring organic polymers and organic/inorganic hybrid materials and controlling blend morphologies at the molecular level are the prerequisites for modern electronic devices including biological sensors, light emitting diodes, memory devices and solar cells. To achieve all-around high performance, multiple organic and inorganic entities, [...] Read more.

Nanostructuring organic polymers and organic/inorganic hybrid materials and controlling blend morphologies at the molecular level are the prerequisites for modern electronic devices including biological sensors, light emitting diodes, memory devices and solar cells. To achieve all-around high performance, multiple organic and inorganic entities, each designed for specific functions, are commonly incorporated into a single device. Accurate arrangement of these components is a crucial goal in order to achieve the overall synergistic effects. We describe here a facile methodology of nanostructuring conjugated polymers and inorganic quantum dots into well-ordered core/shell composite nanofibers through cooperation of several orthogonal non-covalent interactions including conjugated polymer crystallization, block copolymer self-assembly and coordination interactions. Our methods provide precise control on the spatial arrangements among the various building blocks that are otherwise incompatible with one another, and should find applications in modern organic electronic devices such as solar cells. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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2359 KiB

Open AccessArticle

Characterization of Aniline Tetramer by MALDI TOF Mass Spectrometry upon Oxidative and Reductive Cycling

by Rebecca L. Li, Cheng-Wei Lin, Yuanlong Shao, Che Wei Chang, Fu-Kai Yao, Matthew D. Kowal, Haosen Wang, Michael T. Yeung, Shu-Chuan Huang and Richard B. Kaner

Polymers 2016, 8(11), 401; https://doi.org/10.3390/polym8110401 - 15 Nov 2016

Cited by 23 | Viewed by 8279

Abstract

By combining electrochemical experiments with mass spectrometric analysis, it is found that using short chain oligomers to improve the cycling stability of conducting polymers in supercapacitors is still problematic. Cycling tests via cyclic voltammetry over a potential window of 0 to 1.0 V [...] Read more.

By combining electrochemical experiments with mass spectrometric analysis, it is found that using short chain oligomers to improve the cycling stability of conducting polymers in supercapacitors is still problematic. Cycling tests via cyclic voltammetry over a potential window of 0 to 1.0 V or 0 to 1.2 V in a two-electrode device configuration resulted in solid-state electropolymerization and chain scission. Electropolymerization of the aniline tetramer to generate long chain oligomers is shown to be possible despite the suggested decrease in reactivity and increase in intermediate stability with longer oligomers. Because aniline oligomers are more stable towards reductive cycling when compared to oxidative cycling, future conducting polymer/oligomer-based pseudocapacitors should consider using an asymmetric electrode configuration. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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3364 KiB

Open AccessArticle

Understanding the Structural Evolution of Single Conjugated Polymer Chain Conformers

by Adam J. Wise and John K. Grey

Polymers 2016, 8(11), 388; https://doi.org/10.3390/polym8110388 - 3 Nov 2016

Cited by 7 | Viewed by 5930

Abstract

Single molecule photoluminescence (PL) spectroscopy of conjugated polymers has shed new light on the complex structure–function relationships of these materials. Although extensive work has been carried out using polarization and excitation intensity modulated experiments to elucidate conformation-dependent photophysics, surprisingly little attention has been [...] Read more.

Single molecule photoluminescence (PL) spectroscopy of conjugated polymers has shed new light on the complex structure–function relationships of these materials. Although extensive work has been carried out using polarization and excitation intensity modulated experiments to elucidate conformation-dependent photophysics, surprisingly little attention has been given to information contained in the PL spectral line shapes. We investigate single molecule PL spectra of the prototypical conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) which exists in at least two emissive conformers and can only be observed at dilute levels. Using a model based on the well-known “Missing Mode Effect” (MIME), we show that vibronic progression intervals for MEH-PPV conformers can be explained by relative contributions from particular skeletal vibrational modes. Here, observed progression intervals do not match any ground state Raman active vibrational frequency and instead represent a coalescence of multiple modes in the frequency domain. For example, the higher energy emitting “blue” MEH-PPV form exhibits PL maxima at ~18,200 cm⁻¹ with characteristic MIME progression intervals of ~1200–1350 cm⁻¹, whereas the lower energy emitting “red” form peaks at ~17,100 cm⁻¹ with intervals in the range of ~1350–1450 cm⁻¹. The main differences in blue and red MEH-PPV chromophores lie in the intra-chain order, or, planarity of monomers within a chromophore segment. We demonstrate that the Raman-active out-of-plane C–H wag of the MEH-PPV vinylene group (~966 cm⁻¹) has the greatest influence in determining the observed vibronic progression MIME interval. Namely, larger displacements (intensities)—indicating lower intra-chain order—lower the effective MIME interval. This simple model provides useful insights into the conformational characteristics of the heterogeneous chromophore landscape without requiring costly and time-consuming low temperature or single molecule Raman capabilities. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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2604 KiB

Open AccessArticle

Synthesis and Characterization of Two-Dimensional Conjugated Polymers Incorporating Electron-Deficient Moieties for Application in Organic Photovoltaics

by Chuen-Yo Hsiow, Han-Ying Wang, Yu-Hsiang Lin, Rathinam Raja, Syang-Peng Rwei, Wen-Yen Chiu, Chi-An Dai and Leeyih Wang

Polymers 2016, 8(11), 382; https://doi.org/10.3390/polym8110382 - 27 Oct 2016

Cited by 4 | Viewed by 6188

Abstract

A series of novel p-type conjugated copolymers, PTTVBDT, PTTVBDT-TPD, and PTTVBDT-DPP, cooperating benzo[1,2-b:4,5-b′]dithiophene (BDT) and terthiophene-vinylene (TTV) units with/without thieno[3,4-c]pyrrole-4,6-dione (TPD) or pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) via Stille polymerization were synthesized and characterized. Copolymer PTTVBDT shows a low-lying HOMO energy level [...] Read more.

A series of novel p-type conjugated copolymers, PTTVBDT, PTTVBDT-TPD, and PTTVBDT-DPP, cooperating benzo[1,2-b:4,5-b′]dithiophene (BDT) and terthiophene-vinylene (TTV) units with/without thieno[3,4-c]pyrrole-4,6-dione (TPD) or pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) via Stille polymerization were synthesized and characterized. Copolymer PTTVBDT shows a low-lying HOMO energy level and ordered molecular-packing behavior. Furthermore, two terpolymers, PTTVBDT-TPD and PTTVBDT-DPP, display stronger absorption ability, alower-lying HOMO energy level, and preferred molecular orientation, due to the replacement TTV-monomer units with electron-deficient groups. Furthermore, bulk-heterojunction organic solar cells were fabricated using blends of the PTTVBDT-TPD, and PC₆₁BM gave the best power conversion efficiency of 5.01% under the illumination of AM 1.5G, 100 mW·cm⁻²; the short circuit current (J_sc) was 11.65 mA·cm⁻² which displayed a 43.8% improvement in comparison with the PTTVBDT/PC₆₁BM device. These results demonstrate a valid strategy combining the two-dimensional molecular structure with random copolymerization strikes promising conjugated polymers to achieve highly efficient organic photovoltaics. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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13110 KiB

Open AccessArticle

Low Band Gap Donor–Acceptor Type Polymers Containing 2,3-Bis(4-(decyloxy)phenyl)pyrido[4,3-b]pyrazine as Acceptor and Different Thiophene Derivatives as Donors

by Yan Zhang, Xuezhong Liu, Min Wang, Xiaoli Liu and Jinsheng Zhao

Polymers 2016, 8(10), 377; https://doi.org/10.3390/polym8100377 - 24 Oct 2016

Cited by 12 | Viewed by 7214

Abstract

Four donor–acceptor type conducting polymers, namely poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-thiophen-2-yl)pyrido[4,3-b]pyrazine) (P1), poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-butylthiophen-2-yl)pyrido[4,3-b]pyrazine) (P2), poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(4-hexyloxythiophen-2-yl)pyrido[4,3-b]pyrazine) (P3) and poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)pyrido[4,3-b]pyrazine) (P4), containing thiophene or its derivative as the donor and pyrido[4,3-b]pyrazine as the acceptor were prepared and characterized by cyclic voltammetry, scanning electron microscopy, and UV-Vis spectroscopy to detect [...] Read more.

Four donor–acceptor type conducting polymers, namely poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-thiophen-2-yl)pyrido[4,3-b]pyrazine) (P1), poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-butylthiophen-2-yl)pyrido[4,3-b]pyrazine) (P2), poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(4-hexyloxythiophen-2-yl)pyrido[4,3-b]pyrazine) (P3) and poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)pyrido[4,3-b]pyrazine) (P4), containing thiophene or its derivative as the donor and pyrido[4,3-b]pyrazine as the acceptor were prepared and characterized by cyclic voltammetry, scanning electron microscopy, and UV-Vis spectroscopy to detect the influence of the donor units’ strength on the electrochromic performances. The results demonstrated that all of the polymers could be reversibly reduced and oxidized by p-type doping and n-type doping, and showed near-infrared activities and different color changes in p-type doping process. Especially, P3 and P4 showed lower optical band gap than P1 and P2 due to the strong electron-donating hexyloxythiophen group of P3 and ethylenedioxythiophene group of P4. Besides, P3 and P4 displayed the saturated green color at the neutral state and the desirable transparency at the oxidized state. All the polymers displayed desirable optical contrasts, satisfactory coloration efficiency, excellent stability and short switching time, which made the polymers fascinating candidates in the electrochromic device applications. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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2539 KiB

Open AccessArticle

Synthesis of Novel Cobalt-Containing Polysilazane Nanofibers with Fluorescence by Electrospinning

by Qian Zhang, Dechang Jia, Zhihua Yang, Xiaoming Duan, Qingqing Chen and Yu Zhou

Polymers 2016, 8(10), 350; https://doi.org/10.3390/polym8100350 - 17 Oct 2016

Cited by 9 | Viewed by 8145

Abstract

Emission in the nanostructured materials is important in micro/nanoelectronic devices. We report here a strategy for the processing of micron and submicron fibers from a cobalt-containing hyperbranched polysilazane by electrospinning. The electrospun nanofibers have uniform average diameters of ~600 nm and lengths of [...] Read more.

Emission in the nanostructured materials is important in micro/nanoelectronic devices. We report here a strategy for the processing of micron and submicron fibers from a cobalt-containing hyperbranched polysilazane by electrospinning. The electrospun nanofibers have uniform average diameters of ~600 nm and lengths of ~10 μm. The photophysical properties of polycobaltsilazane (PCSN) are studied using UV-VIS and photoluminescence spectroscopies. PCSN fibers display a series of emission peaks between 490 and 615 nm. The Co(II) doping into polysilazane leads to the emission from 465 to 415 nm. The emission wavelength shift of Co(III)-containing polysilazane is specific under 340 and 470 nm excitation wavelengths, respectively, while it is not observed with metal-free polysilazane. Thermogravimetric analysis-Differentical thermal analysis (TGA-DTA) profiles also show good thermostability of the PCSN fibers at 800 °C under Ar atmosphere. The use of PCSN offers both enhanced ceramic yields against ~5 wt % starting material and the fluorescence intensity of polymeric fibers. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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5982 KiB

Open AccessArticle

Relaxation Oscillation with Picosecond Spikes in a Conjugated Polymer Laser

by Wafa Musa Mujamammi, Saradh Prasad, Mohamad S. AlSalhi and Vadivel Masilamani

Polymers 2016, 8(10), 364; https://doi.org/10.3390/polym8100364 - 14 Oct 2016

Cited by 8 | Viewed by 5784

Abstract

Optically pumped conjugated polymer lasers are good competitors for dye lasers, often complementing and occasionally replacing them. This new type of laser material has broad bandwidths and high optical gains comparable to conventional laser dyes. Since the Stokes’ shift is unusually large, the [...] Read more.

Optically pumped conjugated polymer lasers are good competitors for dye lasers, often complementing and occasionally replacing them. This new type of laser material has broad bandwidths and high optical gains comparable to conventional laser dyes. Since the Stokes’ shift is unusually large, the conjugated polymer has a potential for high power laser action, facilitated by high concentration. This paper reports the results of a new conjugated polymer, the poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}](PFO-co-MEH-PPV) material, working in the green region. Also discussed are the spectral and temporal features of the amplified spontaneous emissions (ASE) from the conjugated polymer PFO-co-MEH-PPV in a few solvents. When pumped by the third harmonic of the Nd:YAG laser of 10 ns pulse width, the time-resolved spectra of the ASE show relaxation oscillations and spikes of 600 ps pulses. To the best of our knowledge, this is the first report on relaxation oscillations in conjugated-polymer lasers. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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3542 KiB

Open AccessCommunication

Hedgehog Buckyball: A High-Symmetry Complete Polyhedral Oligomeric Silsesquioxane (POSS)

by Yu Hu, You Wang, Hong You and Di Wang

Polymers 2016, 8(8), 315; https://doi.org/10.3390/polym8080315 - 22 Aug 2016

Cited by 5 | Viewed by 5142

Abstract

In this study, we report UV-MALDI-TOF MS evidence of a fullerene-like silsesquioxane, a high-symmetry polyhedral oligomeric silsesquioxane (POSS or SSO) formulated as R₆₀-Si₆₀O₉₀ or T₆₀ (T = RSiO_1.5). The T₆₀ preparation can be performed [...] Read more.

In this study, we report UV-MALDI-TOF MS evidence of a fullerene-like silsesquioxane, a high-symmetry polyhedral oligomeric silsesquioxane (POSS or SSO) formulated as R₆₀-Si₆₀O₉₀ or T₆₀ (T = RSiO_1.5). The T₆₀ preparation can be performed using a normal hydrolytic condensation of [(3-methacryloxy)propyl]trimethoxysilane (MPMS) as an example. Theoretically, four 3sp³ hybrid orbitals (each containing an unpaired electron) of a Si atom are generated before the bond formation. Then it bonds to another four atom electrons using the four generated hybrid orbitals which produced a stable configuration. This fullerene-like silsesquioxane should exhibit much more functionality, activity and selectivity and is easier to assemble than the double bonds in a fullerene. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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1970 KiB

Open AccessArticle

A Facile Route to Synthesize Nanographene Reinforced PBO Composites Fiber via in Situ Polymerization

by Mingqiang Wang, Shuai Zhang, Jidong Dong, Yuanjun Song, Jiao Mao, Huaquan Xie, Yue Qian, Yudong Huang and Zaixing Jiang

Polymers 2016, 8(7), 251; https://doi.org/10.3390/polym8070251 - 4 Jul 2016

Cited by 12 | Viewed by 6454

Abstract

The polymer matrix with introduced carbon-based nanofiber displays fascinating properties. They have inspired extensive research on the synthesis of polymer composites, which have been applied in catalysis, electronics, and energy storage. In this report, we reported a facile and efficient method to prepare [...] Read more.

The polymer matrix with introduced carbon-based nanofiber displays fascinating properties. They have inspired extensive research on the synthesis of polymer composites, which have been applied in catalysis, electronics, and energy storage. In this report, we reported a facile and efficient method to prepare poly(p-phenylene benzobisoxazole) (PBO)/nanographene (PNG) composites fibers via in-situ polymerization, accompanied by the reduction from (nanographene oxide) NGO to (nanographene) NG. By tuning the ratio of feeding PBO monomer to NGO, various composites fibers with 0.1–1 wt % contents of NG were obtained. The efficient PBO chains grafting made NG uniformly disperse in the PBO matrix, and it also increased the uniformity of the packing orientation of PBO chains. Consequently, the tensile strength, tensile modulus, and thermal stability of the obtained PNG composites fibers had been improved significantly. In addition, the composites fibers with 0.5 wt % NG exhibited a 25% increment in tensile strength, and a 41% enhancement in tensile modulus compared with neat PBO fibers. It reveals an excellent reinforcement to PBO composites fibers with NG. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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9132 KiB

Open AccessArticle

Applications of Tris(4-(thiophen-2-yl)phenyl)amine- and Dithienylpyrrole-based Conjugated Copolymers in High-Contrast Electrochromic Devices

by Tzi-Yi Wu and Hsin-Hua Chung

Polymers 2016, 8(6), 206; https://doi.org/10.3390/polym8060206 - 27 May 2016

Cited by 29 | Viewed by 5393

Abstract

Tris(4-(thiophen-2-yl)phenyl)amine- and dithienylpyrrole-based copolymers (P(TTPA-co-DIT) and P(TTPA-co-BDTA)) were electropolymerized on ITO electrode by applying constant potentials of 1.0, 1.1, and 1.2 V. Spectroelectrochemical investigations revealed that P(TTPA-co-DIT) film displayed more color changes than P(TTPA-co-BDTA) film. [...] Read more.

Tris(4-(thiophen-2-yl)phenyl)amine- and dithienylpyrrole-based copolymers (P(TTPA-co-DIT) and P(TTPA-co-BDTA)) were electropolymerized on ITO electrode by applying constant potentials of 1.0, 1.1, and 1.2 V. Spectroelectrochemical investigations revealed that P(TTPA-co-DIT) film displayed more color changes than P(TTPA-co-BDTA) film. The P(TTPA-co-DIT) film is yellow in the neutral state, yellowish-green and green in the intermediate state, and blue (1.2 V) in highly oxidized state. The ∆T_max of the P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were measured as 60.3% at 1042 nm and 47.1% at 1096 nm, respectively, and the maximum coloration efficiency (η) of P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were calculated to be 181.9 cm²·C⁻¹ at 1042 nm and 217.8 cm²·C⁻¹ at 1096 nm, respectively, in an ionic liquid solution. Dual type electrochromic devices (ECDs) consisting of P(TTPA-co-DIT) (or P(TTPA-co-BDTA)) anodic copolymer, ionic liquid-based electrolyte, and poly(3,4-(2,2-diethylpropylenedioxy)thiophene) (PProDOT-Et₂) cathodic polymer were constructed. P(TTPA-co-BDTA)/PProDOT-Et₂ ECD showed high ΔT_max (48.1%) and high coloration efficiency (649.4 cm²·C⁻¹) at 588 nm. Moreover, P(TTPA-co-DIT)/PProDOT-Et₂ and P(TTPA-co-BDTA)/PProDOT-Et₂ ECDs displayed satisfactory optical memory and long term switching stability. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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Review

Jump to: Research

8221 KiB

Open AccessReview

Recent Advances in Conjugated Polymer-Based Microwave Absorbing Materials

by Ying Wang, Yunchen Du, Ping Xu, Rong Qiang and Xijiang Han

Polymers 2017, 9(1), 29; https://doi.org/10.3390/polym9010029 - 14 Jan 2017

Cited by 120 | Viewed by 13201

Abstract

Microwave absorbing materials (MAMs) are paving the way for exciting applications in electromagnetic (EM) pollution precaution and national defense security, as they offer an advanced alternative to conventional reflection principles to fundamentally eliminate the EM waves. Conjugated polymer (CP)-based composites appear as a [...] Read more.

Microwave absorbing materials (MAMs) are paving the way for exciting applications in electromagnetic (EM) pollution precaution and national defense security, as they offer an advanced alternative to conventional reflection principles to fundamentally eliminate the EM waves. Conjugated polymer (CP)-based composites appear as a promising kind of MAM with the desirable features of low density and high performance. In this review, we introduce the theory of microwave absorption and summarize recent advances in the fabrication of CP-based MAMs, including rational design of the microstructure of pure conjugated polymers and tunable chemical integration with magnetic ferrites, magnetic metals, transition metal oxides, and carbon materials. The key point of enhancing microwave absorption in CP-based MAMs is to regulate their EM properties, improve matching of characteristic impedance, and create diversified loss mechanisms. The examples presented in this review will provide new insights into the design and preparation of CP-based composites that can satisfy the high demands of the oncoming generation of MAMs. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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Open AccessReview

Development of Conjugated Polymers for Memory Device Applications

by Hung-Ju Yen, Changsheng Shan, Leeyih Wang, Ping Xu, Ming Zhou and Hsing-Lin Wang

Polymers 2017, 9(1), 25; https://doi.org/10.3390/polym9010025 - 12 Jan 2017

Cited by 37 | Viewed by 11228

Abstract

This review summarizes the most widely used mechanisms in memory devices based on conjugated polymers, such as charge transfer, space charge traps, and filament conduction. In addition, recent studies of conjugated polymers for memory device applications are also reviewed, discussed, and differentiated based [...] Read more.

This review summarizes the most widely used mechanisms in memory devices based on conjugated polymers, such as charge transfer, space charge traps, and filament conduction. In addition, recent studies of conjugated polymers for memory device applications are also reviewed, discussed, and differentiated based on the mechanisms and structural design. Moreover, the electrical conditions of conjugated polymers can be further fine-tuned by careful design and synthesis based on the switching mechanisms. The review also emphasizes and demonstrates the structure-memory properties relationship of donor-acceptor conjugated polymers for advanced memory device applications. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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Open AccessReview

Heteroatom-Doped Carbon Nanostructures Derived from Conjugated Polymers for Energy Applications

by Yanzhen He, Xijiang Han, Yunchen Du, Bin Zhang and Ping Xu

Polymers 2016, 8(10), 366; https://doi.org/10.3390/polym8100366 - 17 Oct 2016

Cited by 44 | Viewed by 9878

Abstract

Heteroatom-doped carbon materials have been one of the most remarkable families of materials with promising applications in fuel cells, supercapacitors, and batteries. Among them, conjugated polymer (CP)-derived heteroatom-doped carbon materials exhibit remarkable electrochemical performances because the heteroatoms can be preserved at a relatively [...] Read more.

Heteroatom-doped carbon materials have been one of the most remarkable families of materials with promising applications in fuel cells, supercapacitors, and batteries. Among them, conjugated polymer (CP)-derived heteroatom-doped carbon materials exhibit remarkable electrochemical performances because the heteroatoms can be preserved at a relatively high content and keep stable under harsh working conditions. In this review, we summarized recent advances in the rational design and various applications of CP-derived heteroatom-doped carbon materials, including polyaniline (PANI), polypyrrole (PPy), and their ramification-derived carbons, as well as transition metal-carbon nanocomposites. The key point of considering CP-derived heteroatom-doped carbon materials as important candidates of electrode materials is that CPs contain only nonmetallic elements and some key heteroatoms in their backbones which provide great chances for the synthesis of metal-free heteroatom-doped carbon nanostructures. The presented examples in this review will provide new insights in designing and optimizing heteroatom-doped carbon materials for the development of anode and cathode materials for electrochemical device applications. Full article

(This article belongs to the Special Issue Conjugated Polymers 2016)

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