共查询到20条相似文献,搜索用时 31 毫秒
1.
Anja Car Chrtomir Stropnik Wilfredo Yave Klaus‐Viktor Peinemann 《Advanced functional materials》2008,18(18):2815-2823
This paper reports the design of a tailor made polymeric membrane by using poly(ethylene oxide)–poly(butylene terephthalate) (PEO‐PBT) multi‐block copolymers. Their properties are controlled by the fraction of the PEO phase and its molecular weight. To explain the effect of structural changes in copolymer membranes, transport properties of four gases (CO2, H2, N2, and CH4) are discussed. After characterization, the two best copolymers are selected in order to prepare tailor made blends by adding poly(ethylene glycol) (PEG). The best selected copolymer that contained 55 wt. % of 4000 g mol−1 PEO produced a blend with high CO2 permeability (∼190 barrer), which is twice the permeability of the pure copolymer. At the same time, an enhancement of CO2/H2 selectivity is observed (∼13). These results suggest that the morphology of PEO‐PBT can be well controlled by the addition of low‐molecular‐weight PEG, and consequently the gas transport properties can be tuned. 相似文献
2.
Extended porous silica films with thicknesses in the range of 60 to 130 μm and pores on both the meso‐ and macroscale have been prepared by simultaneously using porous membrane templates and amphiphilic supramolecular aggregates as porogens. The macropore size is determined by the cellulose acetate or polyamide membrane structure and the mesopores by the chosen ethylene‐oxide‐based molecular self‐assembly (block copolymer or non‐ionic surfactants). Both the template and the porogen are removed during an annealing step leaving the amorphous silica material with a porous structure that results from sol–gel chemistry occurring in the aqueous domains of the amphiphilic liquid‐crystalline phases and casting of the initial template membrane. The surface area and total pore volume of the inorganic films vary from 473 to 856 m2 g–1, and 0.50 to 0.73 cm3 g–1, respectively, depending on the choice of template and porogen. The combined benefits of both macro‐ and mesopores can potentially be obtained in one film. Such materials are envisaged to have applications in areas of large molecule (biomolecule) separation and catalysis. Enhanced gas and liquid flow rates through such membranes, due to the presence of the larger pores, also makes them attractive as supports for other catalytic materials. 相似文献
3.
Yu‐Hsiang Chang Chia‐Wei Ku Yi‐Hua Zhang Hsiang‐Chen Wang Jung‐Yao Chen 《Advanced functional materials》2020,30(21)
The exotic photophysical properties of organic–inorganic hybrid perovskite with long exciton lifetimes and small binding energy have appeared as promising front‐runners for next‐generation non‐volatile flash photomemory. However, the long photo‐programming time of photomemory limits its application on light‐fidelity (Li‐Fi), which requires high storage capacity and short programming times. Herein, the spatially addressable perovskite in polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO)/perovskite composite film as an photoactive floating gate is demonstrated to elucidate the effect of morphology on the photo‐responsive characteristics of photomemory. The chelation between lead ion and PEO segment promotes the anti‐solvent functionalities of the perovskite/PS‐b‐PEO composite film, thus allowing the solution‐processable poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) to act as the active channel. Through manipulating the interfacial area between perovskite and P3HT, fast photo‐induced charge transfer rate of 0.056 ns?1, high charge transfer efficiency of 89%, ON/OFF current ratio of 104, and extremely low programming time of 5 ms can be achieved. This solution‐processable and fast photo‐programmable non‐volatile flash photomemory can trigger the practical application on Li‐Fi. 相似文献
4.
Elina Ploshnik Karol M. Langner Amit Halevi Meirav Ben‐Lulu Axel H. E. Müller Johannes G. E. M. Fraaije G. J. Agur Sevink Roy Shenhar 《Advanced functional materials》2013,23(34):4215-4226
Tailoring the size and surface chemistry of nanoparticles allows one to control their position in a block copolymer, but this is usually limited to one‐dimensional distribution across domains. Here, the hierarchical assembly of poly(ethylene oxide)‐stabilized gold nanoparticles (Au‐PEO) into hexagonally packed clusters inside mesostructured ultrathin films of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) is described. A close examination of the structural evolution at different nanoparticle filling fractions and PEO ligand molecular weights suggests that the mechanism leading to this structure‐within‐structure is the existence of two phase separation processes operating on different time scales. The length of the PEO ligand is shown to influence not only the interparticle distances but also the phase separation processes. These conclusions are supported by novel mesoscopic simulations, which provide additional insight into the kinetic and thermodynamic factors that are responsible for this behavior. 相似文献
5.
Yunxia Hu Debasis Samanta Sangram S. Parelkar Sung Woo Hong Qian Wang Thomas P. Russell Todd Emrick 《Advanced functional materials》2010,20(20):3603-3612
Controlled free radical polymerization chemistry is used to graft polymer chains to the corona of horse spleen ferritin (HSF) nanocages. Specifically, poly(methacryloyloxyethyl phosphorylcholine) (polyMPC) and poly(PEG methacrylate) (polyPEGMA) chains are grafted onto the nanocages by atom transfer radical polymerization (ATRP), in which the molecular weight of the polymer grafts is controlled by the monomer‐to‐initiator feed ratio. PolyMPC and polyPEGMA‐grafted ferritin show a generally suppressed inclusion into diblock copolymer films relative to native ferritin, and the polymer coating is seen to mask the ferritin nanocages from antibody recognition. The solubility of polyPEGMA‐coated ferritin in organic solvents enables its processing with polystyrene‐block‐poly(ethylene oxide) copolymers, and selective integration into the PEO domains of microphase‐separated copolymer structures. 相似文献
6.
Yanda Fu Kai Yang Shida Xue Weihan Li Shiming Chen Yongli Song Zhibo Song Wenguang Zhao Yunlong Zhao Feng Pan Luyi Yang Xueliang Sun 《Advanced functional materials》2023,33(10):2210845
High Li+ conductivity, good interfacial compatibility and high mechanical strength are desirable for practical utilization of all-solid-state electrolytes. In this study, by introducing Li6.4La3Zr1.4Ta0.6O12 (LLZTO) with surface defects into poly(ethylene oxide) (PEO), a composite solid electrolyte (OV-LLZTO/PEO) is prepared. The surface defects serve as anchoring points for oxygen atoms of PEO chains, forming a firmly bonded polymer-ceramic interface. This bonding effect effectively prevents the agglomeration of LLZTO particles and crystallization of PEO domains, forming a homogeneous electrolyte membrane exhibiting high mechanical strength, reduced interfacial resistance with electrodes as well as improved Li+ conductivity. Owing to these favorable properties, OV-LLZTO/PEO can be operated under a high current density (0.7 mA cm−2) in a Li–Li symmetric cell without short circuit. Above all, solid-state full-cells employing OV-LLZTO/PEO deliver state-of-the-art rate capability (8 C), power density and capacity retention. As a final proof of concept study, flexible pouch cells are assembled and tested, exhibiting high cycle stability under 5 C and excellent safety feature under abusive working conditions. Through manipulating the interfacial interactions between polymer and inorganic electrolytes, this study points out a new direction to optimizing the performance of all-solid-state batteries. 相似文献
7.
D. H. K. Murthy Armantas Melianas Zheng Tang Gytis Juška Kȩstutis Arlauskas Fengling Zhang Laurens D. A. Siebbeles Olle Inganäs Tom J. Savenije 《Advanced functional materials》2013,23(34):4262-4268
Bimolecular charge carrier recombination in blends of a conjugated copolymer based on a thiophene and quinoxaline (TQ1) with a fullerene derivative ((6,6)‐phenyl‐C71‐butyric acidmethyl ester, PC71BM) is studied by two complementary techniques. TRMC (time‐resolved microwave conductance) monitors the conductance of photogenerated mobile charge carriers locally on a timescale of nanoseconds, while using photo‐CELIV (charge extraction by linearly increasing voltage) charge carrier dynamics are monitored on a macroscopic scale and over tens of microseconds. Despite these significant differences in the length and time scales, both techniques show a reduced Langevin recombination with a prefactor ζ close to 0.05. For TQ1:PC71BM blends, the ζ value is independent of temperature. On comparing TRMC data with electroluminescence measurements it is concluded that the encounter complex and the charge transfer state have very similar energetic properties. The ζ value for annealed poly(3‐hexylthiophene) (P3HT):(6,6)‐phenyl‐C61‐butyric acid methyl ester (PC61BM) is approximately 10?4, while for blend systems containing an amorphous polymer ζ values are close to 1. These large differences can be related to the extent of charge delocalization of opposite charges in an encounter complex. Insight is provided into factors governing the bimolecular recombination process, which forms a major loss mechanism limiting the efficiency of polymer solar cells. 相似文献
8.
Pablo Docampo Stefan Guldin Morgan Stefik Priti Tiwana M. Christopher Orilall Sven Hüttner Hiroaki Sai Ulrich Wiesner Ulrich Steiner Henry J. Snaith 《Advanced functional materials》2010,20(11):1787-1796
Hybrid dye‐sensitized solar cells are typically composed of mesoporous titania (TiO2), light‐harvesting dyes, and organic molecular hole‐transporters. Correctly matching the electronic properties of the materials is critical to ensure efficient device operation. In this study, TiO2 is synthesized in a well‐defined morphological confinement that arises from the self‐assembly of a diblock copolymer—poly(isoprene‐b‐ethylene oxide) (PI‐b‐PEO). The crystallization environment, tuned by the inorganic (TiO2 mass) to organic (polymer) ratio, is shown to be a decisive factor in determining the distribution of sub‐bandgap electronic states and the associated electronic function in solid‐state dye‐sensitized solar cells. Interestingly, the tuning of the sub‐bandgap states does not appear to strongly influence the charge transport and recombination in the devices. However, increasing the depth and breadth of the density of sub‐bandgap states correlates well with an increase in photocurrent generation, suggesting that a high density of these sub‐bandgap states is critical for efficient photo‐induced electron transfer and charge separation. 相似文献
9.
Fazel Zare Bidoky Boxin Tang Rui Ma Krystopher S. Jochem Woo Jin Hyun Donghoon Song Steven J. Koester Timothy P. Lodge C. Daniel Frisbie 《Advanced functional materials》2020,30(20)
A facile, high‐resolution patterning process is introduced for fabrication of electrolyte‐gated transistors (EGTs) and circuits using a photo‐crosslinkable ion gel and stencil‐based screen printing. The photo‐crosslinkable gel is based on a triblock copolymer incorporating UV‐sensitive terminal azide functionality and a common ionic liquid. Using this material in conjunction with conventional photolithography and stenciling techniques, well‐defined 0.5–1 μm thick ion gel films are patterned on semiconductor channels as narrow as 10 μm. The resulting n‐type ZnO EGTs display high electron mobility (>2 cm2 Vs?1) and on/off current ratios (>105). Further, EGT‐based inverters exhibit static gains >23 at supply voltages below 3 V, and five‐stage EGT ring oscillator circuits display dynamic propagation delays of 50 μs per stage. In general, the screen printing and photo‐crosslinking strategy provides a clean room‐compatible method to fabricate EGT circuits with improved sensitivity (gain) and computational power (gain × oscillating frequency). Detailed device analysis indicates that significantly shorter delay times, of order 1 μs, can be obtained by improving the ion gel conductance. 相似文献
10.
Anthony J. Kim Mark S. Kaucher Kevin P. Davis Mihai Peterca Mohammad R. Imam Natalie A. Christian Dalia H. Levine Frank S. Bates Virgil Percec Daniel A. Hammer 《Advanced functional materials》2009,19(18):2930-2936
The ability to add synthetic channels to polymersome (polymer vesicle) membranes could lead to novel membrane composites with unique selectivity and permeability. Proton transport through two different synthetic pores, self‐assembled from either a dendritic dipeptide, (6Nf‐3,4‐3,5)12G2‐CH2‐Boc‐L‐Tyr‐L‐Ala‐OMe, or a dendritic ester, (R)‐4Bp‐3,4‐dm8G1‐COOMe, incorporated into polymersome membranes are studied. Polymersomes provide an excellent platform for studying such transport processes due to their robustness and mechanical and chemical stability compared to liposomes. It is found that the incorporated dendritic dipeptide and dendritic ester assemble into stable helical pores in the poly(ethylene oxide)‐polybutadiene (PEO‐PBD) polymersomes but not in the poly(2‐methyloxazoline)‐poly(dimethylsiloxane)‐poly(2‐methyl oxazoline) (PMOX‐PDMS‐PMOX) polymersomes. The incorporation is confirmed by circular dichroism (CD), changes in purely synthetic mechanical strength (e.g., areal expansion modulus) as assessed by micropipette aspiration, and cryo‐TEM. In addition to the structural analyses, a transport measurement shows the incorporated dendritic helical pores allow facile transport of protons across the polymersome membranes after up to one month of storage. This integration of synthetic porous channels with polymersome substrates could provide a valuable tool for studying active transport processes in a composite membrane. These composites will ultimately expand the family of biologically inspired porous‐membrane mimics. 相似文献
11.
Jiliang Qiu Xinyu Liu Rusong Chen Qinghao Li Yi Wang Penghao Chen Luyu Gan Sang‐Jun Lee Dennis Nordlund Yijin Liu Xiqian Yu Xuedong Bai Hong Li Liquan Chen 《Advanced functional materials》2020,30(22)
Poly(ethylene oxide) (PEO)‐based solid electrolytes are expected to be exploited in solid‐state batteries with high safety. Its narrow electrochemical window, however, limits the potential for high voltage and high energy density applications. Herein the electrochemical oxidation behavior of PEO and the failure mechanisms of LiCoO2‐PEO solid‐state batteries are studied. It is found that although for pure PEO it starts to oxidize at a voltage of above 3.9 V versus Li/Li+, the decomposition products have appropriate Li+ conductivity that unexpectedly form a relatively stable cathode electrolyte interphase (CEI) layer at the PEO and electrode interface. The performance degradation of the LiCoO2‐PEO battery originates from the strong oxidizing ability of LiCoO2 after delithiation at high voltages, which accelerates the decomposition of PEO and drives the self‐oxygen‐release of LiCoO2, leading to the unceasing growth of CEI and the destruction of the LiCoO2 surface. When LiCoO2 is well coated or a stable cathode LiMn0.7Fe0.3PO4 is used, a substantially improved electrochemical performance can be achieved, with 88.6% capacity retention after 50 cycles for Li1.4Al0.4Ti1.6(PO4)3 coated LiCoO2 and 90.3% capacity retention after 100 cycles for LiMn0.7Fe0.3PO4. The results suggest that, when paired with stable cathodes, the PEO‐based solid polymer electrolytes could be compatible with high voltage operation. 相似文献
12.
Layer‐by‐Layer Conjugated Extension of a Semiconducting Polymer for High‐Performance Organic Field‐Effect Transistor
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Mi Jang Se Hyun Kim Han‐Koo Lee Yun‐Hi Kim Hoichang Yang 《Advanced functional materials》2015,25(25):3833-3839
A donor–acceptor (D–A) semiconducting copolymer, PDPP‐TVT‐29, comprising a diketopyrrolopyrrole (DPP) derivative with long, linear, space‐separated alkyl side‐chains and thiophene vinylene thiophene (TVT) for organic field‐effect transistors (OFETs) can form highly π‐conjugated structures with an edge‐on molecular orientation in an as‐spun film. In particular, the layer‐like conjugated film morphologies can be developed via short‐term thermal annealing above 150 °C for 10 min. The strong intermolecular interaction, originating from the fused DPP and D–A interaction, leads to the spontaneous self‐assembly of polymer chains within close proximity (with π‐overlap distance of 3.55 Å) and forms unexpectedly long‐range π‐conjugation, which is favorable for both intra‐ and intermolecular charge transport. Unlike intergranular nanorods in the as‐spun film, well‐conjugated layers in the 200 °C‐annealed film can yield more efficient charge‐transport pathways. The granular morphology of the as‐spun PDPP‐TVT‐29 film produces a field‐effect mobility (μ FET) of 1.39 cm2 V?1 s?1 in an OFET based on a polymer‐treated SiO2 dielectric, while the 27‐Å‐step layered morphology in the 200 °C‐annealed films shows high μ FET values of up to 3.7 cm2 V?1 s?1. 相似文献
13.
Ozlem Sel Aurélien Soulès Bruno Améduri Bernard Boutevin Christel Laberty‐Robert Gérard Gebel Clément Sanchez 《Advanced functional materials》2010,20(7):1090-1098
Hybrid organic/inorganic membranes that include a functionalized (‐SO3H), interconnected silica network, a non‐porogenic organic matrix, and a ‐SO3H‐functionalized terpolymer are synthesized through a sol–gel‐based strategy. The use of a novel crosslinkable poly(vinylidene fluoride‐ter‐perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene sulfonyl fluoride)‐ter‐vinyltriethoxysilane) (poly(VDF‐ter‐PFSVE‐ter‐VTEOS)) terpolymer allows a multiple tuning of the different interfaces to produce original hybrid membranes with improved properties. The synthesized terpolymer and the composite membranes are characterized, and the proton conductivity of a hybrid membrane in the absence of the terpolymer is promising, since 8 mS cm?1 is reached at room temperature, immersed in water, with an experimental ion‐exchange‐capacity (IECexp) value of 0.4 meq g?1. Furthermore, when the composite membranes contain the interfaced terpolymer, they exhibit both a higher proton conductivity (43 mS cm?1 at 65 °C under 100% relative humidity) and better stability than the standard hybrid membrane, arising from the occurrence of a better interface between the inorganic silica and the poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (poly(VDF‐co‐HFP)) copolymer network. Accordingly, the hybrid SiO2‐SO3H/terpolymer/poly(VDF‐co‐HFP) copolymer membrane has potential use as an electrolyte in a polymer‐electrolyte‐membrane fuel cell operating at intermediate temperatures. 相似文献
14.
Unraveling the Influence of Lanthanide Ions on Intra‐ and Inter‐Molecular Electronic Processes in Fe10Ln10 Nano‐Toruses
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Amer Baniodeh Yu Liang Christopher E. Anson Nicola Magnani Annie K. Powell Andreas‐Neil Unterreiner Simon Seyfferle Michael Slota Martin Dressel Lapo Bogani Karin Goß 《Advanced functional materials》2014,24(40):6280-6290
We investigated the electronic properties of the molecular magnetic nanotoruses [FeIII 10LnIII 10(Me‐tea)10(Me‐teaH)10(NO3)10], examining the dependence on the lanthanide (Ln) of both the intra and intermolecular electronic channels. Using femtosecond absorption spectroscopy we show that the intramolecular electronic channels follow a three‐step process, which involves vibrational cooling and crossing to shallow states, followed by recombination. A comparison with the energy gaps showed a relationship between trap efficiency and gaps, indicating that lanthanide ions create trap states to form excitons after photo‐excitation. Using high‐resistance transport measurements and scaling techniques, we investigated the intermolecular transport, demonstrating the dominant role of surface‐limited transport channels and the presence of different types of charge traps. The intermolecular transport properties can be rationalized in terms of a hopping model, and a connection is provided to the far‐IR spectroscopic properties. Comparison between intra and intermolecular processes highlights the role of the excited electronic states and the recombination processes, showing the influence of Kramers parity on the overall mobility. 相似文献
15.
Facile Photo‐Crosslinking of Azide‐Containing Hole‐Transporting Polymers for Highly Efficient,Solution‐Processed,Multilayer Organic Light Emitting Devices
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Junwoo Park Changyeon Lee Jihye Jung Hyunbum Kang Ki‐Hyun Kim Biwu Ma Bumjoon J. Kim 《Advanced functional materials》2014,24(48):7588-7596
A novel framework of azide containing photo‐crosslinkable, conducting copolymer, that is, poly(azido‐styrene)‐random‐poly(triphenylamine) (X‐PTPA), is reported as a hole‐transporting material for efficient solution‐processed, multi‐layer, organic light emitting diodes (OLEDs). A facile and energy‐efficient crosslinking process is demonstrated with UV irradiation (254 nm, 2 mW/cm2) at a short exposure time (5 min). By careful design of X‐PTPA, in which 5 mol% of the photo‐crosslinkable poly(azido‐styrene) is copolymerized with hole‐transporting poly(triphenylamine) (X‐PTPA‐5), the adverse effect of the crosslinking of azide moieties is prevented to maximize the performances of X‐PTPA‐5. Since the photo‐crosslinking chemistry of azide molecules does not involve any photo‐initiators, superior hole‐transporting ability is achieved, producing efficient devices. To evaluate the performances of X‐PTPA‐5 as a hole‐transporting/electron‐blocking layer, Ir(ppy)3‐based, solution‐processable OLEDs are fabricated. The results show high EQE (11.8%), luminous efficiency (43.7 cd/A), and power efficiency (10.4 lm/W), which represent about twofold enhancement over the control device without X‐PTPA‐5 film. Furthermore, micro‐patterned OLEDs with the photo‐crosslinkable X‐PTPA‐5 can be fabricated through standard photolithography. The versatility of this approach is also demonstrated by introducing the same azide moiety into other hole‐transporting materials such as poly(carbazole) (X‐PBC). 相似文献
16.
Zhuang Liu Feng Luo Xiao‐Jie Ju Rui Xie Tao Luo Yi‐Meng Sun Liang‐Yin Chu 《Advanced functional materials》2012,22(22):4742-4750
A novel positively K+‐responsive membrane with functional gates driven by host‐guest molecular recognition is prepared by grafting poly(N‐isopropylacrylamide‐co‐acryloylamidobenzo‐15‐crown‐5) (poly(NIPAM‐co‐AAB15C5)) copolymer chains in the pores of porous nylon‐6 membranes with a two‐step method combining plasma‐induced pore‐filling grafting polymerization and chemical modification. Due to the cooperative interaction of host‐guest complexation and phase transition of the poly(NIPAM‐co‐AAB15C5), the grafted gates in the membrane pores could spontaneously switch from “closed” state to “open” state by recognizing K+ ions in the environment and vice versa; while other ions (e.g., Na+, Ca2+ or Mg2+) can not trigger such an ion‐responsive switching function. The positively K+‐responsive gating action of the membrane is rapid, reversible, and reproducible. The proposed K+‐responsive gating membrane provide a new mode of behavior for ion‐recognizable “smart” or “intelligent” membrane actuators, which is highly attractive for controlled release, chemical/biomedical separations, tissue engineering, sensors, etc. 相似文献
17.
Hyowon Han Beomjin Jeong Tae Hyun Park Wonhee Cha Suk Man Cho Yeongsik Kim Hong Hee Kim Dongho Kim Do Yeol Ryu Won Kook Choi Cheolmin Park 《Advanced functional materials》2019,29(26)
Ordered nanostructured crystals of thin organic–inorganic metal halide perovskites (OIHPs) are of great interest to researchers because of the dimensional‐dependence of their photoelectronic properties for developing OIHPs with novel properties. Top‐down routes such as nanoimprinting and electron beam lithography are extensively used for nanopatterning OIHPs, while bottom‐up approaches are seldom used. Herein, developed is a simple and robust route, involving the controlled crystallization of the OIHPs templated with a self‐assembled block copolymer (BCP), for fabricating nanopatterned OIHP films with various shapes and nanodomain sizes. When the precursor solution consisting of methylammonium lead halide (MAPbX3, X = Br?, I?) perovskite and poly(styrene)‐block‐poly(2‐vinylpyridine) (PS‐b‐P2VP) is spin‐coated on the substrate, a nanostructured BCP is developed by microphase separation. Spontaneous crystallization of the precursor ions preferentially coordinated with the P2VP domains yields ordered nanocrystals with various nanostructures (cylinders, lamellae, and cylindrical mesh) with controlled domain size (≈40–72 nm). The nanopatterned OIHPs show significantly enhanced photoluminescence (PL) with high resistance to both humidity and heat due to geometrically confining OIHPs in and passivation with the P2VP chains. The self‐assembled OIHP films with high PL performance provide a facile control of color coordinates by color conversion layers in blue‐emitting devices for cool‐white emission. 相似文献
18.
Zahra Hemmat Poya Yasaei Jeremy F. Schultz Liang Hong Leily Majidi Amirhossein Behranginia Louisiane Verger Nan Jiang Michel W. Barsoum Robert F. Klie Amin Salehi‐Khojin 《Advanced functional materials》2019,29(19)
Heat transport across vertical interfaces of heterogeneous 2D materials is usually governed by the weak Van der Waals interactions of the surface‐terminating atoms. Such interactions play a significant role in thermal transport across transition metal carbide and nitride (MXene) atomic layers due to their hydrophilic nature and variations in surface terminations. Here, the metallicity of atomically thin Ti3C2Tz MXene, which is also verified by scanning tunneling spectroscopy for the first time, is exploited to develop a self‐heating/self‐sensing platform to carry out direct‐current annealing experiments in high (<10?8 bar) vacuum, while simultaneously evaluating the interfacial heat transport across a Ti3C2Tz/SiO2 interface. At room temperature, the thermal boundary conductance (TBC) of this interface is found, on average, to increase from 10 to 27 MW m?2 K?1 upon current annealing up to the breakdown limit. In situ heating X‐ray diffraction and X‐ray photo‐electron spectroscopy reveal that the TBC values are mainly affected by interlayer and interface spacing due to the removal of absorbents, while the effect of surface termination is negligible. This study provides key insights into understanding energy transport in MXene nanostructures and other 2D material systems. 相似文献
19.
Gegu Chen Tian Li Chaoji Chen Chengwei Wang Yang Liu Weiqing Kong Dapeng Liu Bo Jiang Shuaiming He Yudi Kuang Liangbing Hu 《Advanced functional materials》2019,29(44)
Here, a highly conductive cationic membrane is developed directly from natural wood via a two‐step process, involving etherification and densification. Etherification bonds the cationic functional group (? (CH3)3N+Cl?) to the cellulose backbone, converting negatively charged (ξ‐potential of ?27.9 mV) wood into positively charged wood (+37.7 mV). Densification eliminates the large pores of the natural wood, leading to a highly laminated structure with the oriented cellulose nanofiber and a high mechanical tensile strength of ≈350 MPa under dry conditions (20 times higher than the untreated counterpart) and ≈98 MPa under wet conditions (×5.5 increase compared to the untreated counterpart). The nanoscale gaps between the cellulose nanofibers act as narrow nanochannels with diameters smaller than the Debye length, which facilitates rapid ion transport that is 25 times higher than the ion conductance of the natural wood at a low KCl concentration of 10 × 10?3 m . The demonstrated cationic wood membrane exhibits enhanced mechanical strength and excellent nanofluidic ion‐transport properties, representing a promising direction for developing high‐performance nanofluidic material from renewable, and abundant nature‐based materials. 相似文献
20.
Yao‐Te Chang So‐Lin Hsu Guan‐Yu Chen Ming‐Hsin Su Thounaojam Avinash Singh Eric Wei‐Guang Diau Kung‐Hwa Wei 《Advanced functional materials》2008,18(16):2356-2365
Intramolecular donor–acceptor structures prepared by covalently binding conjugated octylphenanthrenyl‐imidazole moieties onto the side chains of regioregular poly(3‐hexylthiophene)s exhibit lowered bandgaps and enhanced electron transfer compared to the parent polymer, e.g., conjugation of 90 mol% octylphenanthrenyl‐imidazole moieties onto poly(3‐hexylthiophene) chains reduces the optical bandgap from 1.91 to 1.80 eV, and the electron transfer probability is at least twice as high as that of pure poly(3‐hexylthiophene) when blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester. The lowered bandgap and the fast charge transfer both contribute to much higher external quantum efficiencies, thus much higher short‐circuit current densities for copolymers presenting octylphenanthrenyl‐imidazole moieties, relative to those of pure poly(3‐hexylthiophene)s. The short‐circuit current density of a device prepared from a copolymer presenting 90 mol% octylphenanthrenyl‐imidazole moieties is 13.7 mA · cm?2 which is an increase of 65% compared to the 8.3 mA · cm?2 observable for a device containing pure poly(3‐hexylthiophene). The maximum power conversion efficiency of this particular copolymer is 3.45% which suggest that such copolymers are promising polymeric photovoltaic materials. 相似文献