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A poly (vinyl butyral)/graphene oxide composite with NIR light-induced shape memory effect and solid-state plasticity
摘要： A NIR light-induced shape memory composite with light-induced plasticity was prepared by incorporating graphene oxide (GO) into cross-linked poly (vinyl butyral) (PVB). The cross-linked reaction between PVB and aromatic diisocyanate not only endowed the composites with excellent shape memory properties, but also offered the performance of solid-state plasticity due to the formation of carbamate bonds. The photo-responsive performance was introduced to the system by doping GO, a conventional photothermal reagent, resulting in excellent NIR light-induced shape memory properties and light-induced plasticity. According to the stress relaxation tests, the solid-state plasticity of composites could be regulated by the cross-linked density, GO, catalyst dosage and temperature. Moreover, the composites can be repeatedly programmed to a new permanent shape via a light-induced plasticity process, which still exhibited excellent light-induced shape memory properties even after 5 cycles of reconfiguration. The results demonstrate the promising prospect of these composites as actuator elements for applications in self-deployment devices and soft robotic.
关键词： Smart materials,Functional composites,Shape memory polymers,Polymer-matrix composites (PMCs),Plastic deformation
更新于2025-09-23 15:21:21
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Ratiometric Luminescent Sensor of Picric Acid based on the Dual-Emission Mixed-Lanthanide Coordination Polymer
摘要： Powerful explosive sensors play a key role in public security and environmental protection. Herein we report a series of isostructural lanthanide coordination polymers [Ln2L1.5(NMP)2]n (LnL, Ln = Eu , Gd, Tb, Dy, Ho and Er, H4L = [1,1′:4′,1″-terphenyl]-2′,4,4″,5′-tetracarboxylic acid, NMP = N-methyl-2-pyrrolidone) and mixed-Ln LnL (EuxTb1-xL, EuxGd1-xL, TbxGd1-xL and EuxTb0.02-xGd0.98L). Luminescence studies show that both H4L and GdL emit strong fluorescence and phosphorescence at 77 K while only fluorescence at room temperature, and TbL exhibits strong Tb3+ characteristic emission though the energy difference between the triplet excited state of H4L (20661 cm-1) and the 5D4 energy level of Tb3+ (20500 cm-1) is very small. By doping Eu3+ and Tb3+ into GdL, we obtained EuxTb0.02-xGd0.98L emitting warm white light. For TbL and Tb0.01Gd0.99L showing the dual-emission, upon addition of picric acid (PA) into their suspensions in Tris-HCl buffer, Tb3+ emission decreases slowly, however, the ligand-based emission is sharply quenched, rendering TbL and Tb0.01Gd0.99L excellent single-lanthanide and mixed-lanthanide ratiometric luminescence PA sensor materials, respectively.
关键词： picric acid (PA),ratiometric luminescence sensors,white light emission,metal-organic frameworks (MOFs),Coordination polymers (CPs)
更新于2025-09-23 15:21:21
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Water Impact Resistant and Antireflective Superhydrophobic Surfaces Fabricated by Spray Coating of Nanoparticles: Interface Engineering via End-Grafted Polymers
摘要： Fully transparent and water impact resistant superhydrophobic coatings are of great importance for a range of applications including photovoltaics, photonics, automotive windshields, and building windows. A widely utilized approach to fabricate such coatings involves solution-based deposition of hydrophobic nanoparticles. A central challenge is that these coatings do not simultaneously offer high levels of water repellency, perfect transparence, and water impact resistance. Here we demonstrate that end-grafted polymers present excellent interfaces for spray-coated hydrophobic nanoparticles and enable fabrication of water impact resistant and antireflective superhydrophobic coatings (SHPARCs). Depending on the backbone chemistry and thickness, end-grafted polymers uniquely interacted with the fluorinated nanoparticles, resulting in nanostructured films that provided reduction of reflective losses and protection from the impact of water droplets. Counterintuitively, substrates modified with end-grafted hydrophilic polymers exhibited high water impact resistance: the sliding angle of SHPARC on 12 nm thick end-grafted poly(ethylene glycol) layer was <2° after exposure to 100000 water droplets. SHPARC increased the transparency of the glass substrate by ～5% through omnidirectional antireflectivity. We finally demonstrate application of SHPARC on a large area (156 × 156 mm2) silicon solar cell without significant (<0.23%) reduction of the power conversion efficiency, illustrating the promise of the presented approach in fabrication of self-cleaning photovoltaic modules.
关键词： water impact resistance,antireflective,spray coating,nanoparticles,end-grafted polymers,superhydrophobic coatings
更新于2025-09-23 15:21:21
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Charged solitons in branched conducting polymers
摘要： We consider the dynamics of charged solitons in branched conducting polymers, such as, e.g., trans-polyacetylene. An effective model based on the sine-Gordon equation on metric graphs is used for computing the charge transport and scattering of charge carriers at the polymer branching points. The condition for the ballistic charge carrier transport is revealed.
关键词： metric graphs,charged solitons,charge transport,branched conducting polymers,ballistic transport,sine-Gordon equation
更新于2025-09-23 15:21:21
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Preparing Semiconducting Nanoribbons with Tunable Length and Width via Crystallization-Driven Self-Assembly of a Simple Conjugated Homopolymer
摘要： Precise control of width and length of one-dimensional (1D) semiconducting nanostructures has attracted much attention owing to its potential for optoelectronic applications. However, regulating both their length and width using conjugated polymers or even block copolymers is a huge challenge. To solve this problem, we synthesized a unique conjugated polyacetylene homopolymer by living cyclopolymerization, which spontaneously formed 1D nanoribbons via in situ nanoparticlization. Interestingly, their widths could be controlled from 8 to 41 nm, which were directly proportional to their degree of polymerization. Furthermore, a self-seeding technique via crystallization-driven self-assembly (CDSA) was used to control the length of the nanoribbons up to 5.2 μm with narrow distributions less than 1.1. Interestingly, adding a block copolymer unimer to these nanoribbons produced triblock comicelles by the living CDSA mechanism. Finally, these nanoribbons were visualized directly by super-resolution optical fluorescence microscopy. Now, one can modulate both length and width of 1D nanoribbons simultaneously.
关键词： semiconducting nanostructures,crystallization-driven self-assembly,nanoribbons,optoelectronic applications,conjugated polymers
更新于2025-09-23 15:21:21
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Spectroscopic and Quantum-Chemical Studies of Halogen-Containing Derivatives of Poly-N-Epoxypropylcarbazole
摘要： The results of a study of the optical properties of conducting polymers, namely, derivatives of poly-N-epoxypropylcarbazole (PEPC) with heavy atoms, are presented. It is shown that a heavy atom in the structure of a polymer molecule leads to bathochromic shifts in the absorption, fluorescence, and phosphorescence spectra. This is a consequence of a decrease in the energy of the electron levels due to a change in the electron density distribution over the π-electron system in the chromophores of 2IPEPC and 3BrPEPC. Two bands can be distinguished in the fluorescence spectra of PEPC with heavy atoms, just as in the parent polymer. The emission band with a maximum at 380 nm belongs to the monomer luminescent centers and the long-wavelength emission with a maximum at about 420 nm to the polymer excimers. A heavy atom changes the ratio of the intensities of the monomer and excimer bands. The fluorescence lifetimes also decrease in the presence of a heavy atom. Quantum-chemical estimation of the intramolecular transition constants has shown that the probability of the singlet–triplet intercombination conversion in the halogen-containing PEPCs is higher in PEPC. This leads to a markedly stronger phosphorescence of the iodine and bromine-containing polymers and a shorter luminescence lifetime. The obtained results can be used in the development of composite materials based on photoconductive polymers for photovoltaics and optoelectronics.
关键词： optoelectronics,phosphorescence,conducting polymers,poly-N-epoxypropylcarbazole,fluorescence,heavy atoms,bathochromic shifts,photovoltaics,quantum-chemical estimation
更新于2025-09-23 15:21:21
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Conjugated Polymers Based on Thiazole Flanked Naphthalene Diimide for Unipolar n-Type Organic Field-Effect Transistors
摘要： This paper reports the rational design and synthesis of a novel electron-withdrawing building block, thiazole flanked naphthalene diimide (TzNDI), which offers a coplanar conformation and deep-lying highest occupied molecular orbitals energy level in resulting conjugated polymers. A series of conjugated polymers (PTzNDI-2FT, PTzNDI-T, PTzNDI-Se, and PTzNDI-2T) consisting of TzNDI and different donor units were synthesized and characterized. The polymers all possess a high molecular weight and excellent thermal property. Their intense light absorption in low energy bands suggests an enhanced intramolecular charge transfer. The organic field-effect transistors (OFETs) based on these polymers exhibit unipolar n-type transport characteristics with low off current and high on–off current ratio. More importantly, all the devices exhibit near ideal transfer curves with kink-free transfer characteristics. Among these polymers, PTzNDI-2FT exhibits the highest electron mobility (μe) of 0.57 cm2 V?1 s?1, outperforming the commercial n-type polymer N2200 (0.41 cm2 V?1 s?1) under the same conditions. These results demonstrate that TzNDI is a promising building block for high performance unipolar n-type conjugated polymers in OFETs.
关键词： Unipolar n-Type,Thiazole Flanked Naphthalene Diimide,Conjugated Polymers,Organic Field-Effect Transistors
更新于2025-09-23 15:21:21
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Tuning the Cross-Linker Crystallinity of a Stretchable Polymer Semiconductor
摘要： The cross-linking of conjugated polymers has been demonstrated to be an effective strategy to improve its elastic properties to give deformable semiconductors for plastic electronics. While there have been extensive studies of the structural requirements of the polymer host for good film ductility, no work to date has focused on the relevance of the structural design or chemistry of these cross-linker additives. In this study, urethane groups and tertiary carbon atoms are inserted into the alkyl backbone of perfluorophenyl azide-based cross-linkers to investigate the importance of cross-linker crystallinity with respect to polymer morphology and hence mechanical and electrical properties. Linear cross-linkers with hydrogen bonding from urethane groups readily phase separate and recrystallize in the polymer network to form cross-linked domains that obstruct the strain distribution of the polymer film. Branch cross-linkers with tertiary carbon on the other hand form an evenly cross-linked network in the polymer blend stemming from excellent miscibility and show a 4-fold increase in fracture strain. Furthermore, a stable hole mobility of 0.2 cm2 V?1 s?1 is achieved up to ε = 100%, and a stable hole mobility of 0.1 cm2 V?1 s?1 after 2000 cycles of ε = 25% on fully stretchable organic field-effect transistors.
关键词： cross-linking,deformable semiconductors,cross-linker crystallinity,electrical properties,polymer morphology,elastic properties,plastic electronics,conjugated polymers,mechanical properties
更新于2025-09-23 15:21:21
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p-Doping Poly(3-hexylthiophene) in Solvent Mixtures
摘要： One method to improve the conductivity of conjugated polymers, like poly(3-hexylthiophene) (P3HT), is to “chemically dope” them analogous to inorganic materials. One electron acceptor that has been used in tandem to p-doped P3HT is 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), and recently there has been much interest in the nature of the interactions between F4TCNQ and P3HT in the solution phase. To date, however, there are few reports that investigate the behavior of F4TCNQ-doped P3HT in binary solvent mixtures. The study reported herein is an investigation of F4TCNQ-doped P3HT in mixtures of chloroform (CF) with dichloromethane (DCM) or acetonitrile (AcN), wherein variations in the doping efficiency in these mixtures are observed using UV–vis absorption, Raman, and electron paramagnetic resonance spectroscopic techniques. The contrasting solubility and charge transfer behavior of F4TCNQ-doped P3HT in CF:DCM and CF:AcN show that judicious selection of solvent mixtures may be exploited to improve the doping efficiency and solution processability of p-doped P3HT dispersions.
关键词： dispersions,charge transfer,conjugated polymers,self-assembly
更新于2025-09-23 15:21:21
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Unraveling Doping Capability of Conjugated Polymers for Strategic Manipulation of Electric Dipole Layer toward Efficient Charge Collection in Perovskite Solar Cells
摘要： Developing electrical organic conductors is challenging because of the difficulties involved in generating free charge carriers through chemical doping. To devise a novel doping platform, the doping capabilities of four designed conjugated polymers (CPs) are quantitatively characterized using an AC Hall-effect device. The resulting carrier density is related to the degree of electronic coupling between the CP repeating unit and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), and doped PIDF-BT provides an outstanding electrical conductivity, exceeding 210 S cm?1, mainly due to the doping-assisted facile carrier generation and relatively fast carrier mobility. In addition, it is noted that a slight increment in the electron-withdrawing ability of the repeating unit in each CP diminishes electronic coupling with F4-TCNQ, and severely deteriorates the doping efficiency including the alteration of operating doping mechanism for the CPs. Furthermore, when PIDF-BT with high doping capability is applied to the hole transporting layer, with F4-TCNQ as the interfacial doping layer at the interface with perovskite, the power conversion efficiency of the perovskite solar cell improves significantly, from 17.4% to over 20%, owing to the ameliorated charge-collection efficiency. X-ray photoelectron spectroscopy and Kelvin probe analyses verify that the improved solar cell performance originates from the increase in the built-in potential because of the generation of electric dipole layer.
关键词： conjugated polymers,conducting polymers,doping,molecular electronics,solar cells
更新于2025-09-23 15:21:01