The development of conjugated alternating donor–acceptor (D–A) copolymers with various electron‐rich and electron‐deficient units in polymer backbones has boosted the power conversion efficiency (PCE) over 17% for polymer solar cells (PSCs) over the past two decades. However, further enhancements in PCEs for PSCs are still imperative to compensate their imperfect stability for fulfilling practical applications. Meanwhile development of these alternating D–A copolymers is highly demanding in creative design and syntheses of novel D and/or A monomers. In this regard, when being possible to adopt an existing monomer unit as a third component from its libraries, either a D′ unit or an A′ moiety, to the parent D–A type polymer backbones to afford conjugated D–A terpolymers, it will give a facile and cost‐effective method to improve their light absorption and tune energy levels and also interchain packing synergistically. Moreover, the rationally controlled stoichiometry for these components in such terpolymers also provides access for further fine‐tuning these factors, thus resulting in high‐performance PSCs. Herein, based on their unique features, the recent progress of conjugated D–A terpolymers for efficient PSCs is reviewed and it is discussed how these factors influence their photovoltaic performance, for providing useful guidelines to design new terpolymers toward high‐efficiency PSCs. 相似文献
Photoelectrochemical (PEC) water reduction, converting solar energy into environmentally friendly hydrogen fuel, requires delicate design and synthesis of semiconductors with appropriate bandgaps, suitable energy levels of the frontier orbitals, and high intrinsic charge mobility. In this work, the synthesis of a novel bithiophene‐bridged donor–acceptor‐based 2D sp2‐carbon‐linked conjugated polymer (2D CCP) is demonstrated. The Knoevenagel polymerization between the electron‐accepting building block 2,3,8,9,14,15‐hexa(4‐formylphenyl) diquinoxalino[2,3‐a:2′,3′‐c]phenazine (HATN‐6CHO) and the first electron‐donating linker 2,2′‐([2,2′‐bithiophene]‐5,5′‐diyl)diacetonitrile (ThDAN) provides the 2D CCP‐HATNThDAN (2D CCP‐Th). Compared with the corresponding biphenyl‐bridged 2D CCP‐HATN‐BDAN (2D CCP‐BD), the bithiophene‐based 2D CCP‐Th exhibits a wide light‐harvesting range (up to 674 nm), a optical energy gap (2.04 eV), and highest energy occupied molecular orbital–lowest unoccupied molecular orbital distributions for facilitated charge transfer, which make 2D CCP‐Th a promising candidate for PEC water reduction. As a result, 2D CCP‐Th presents a superb H2‐evolution photocurrent density up to ≈7.9 µA cm?2 at 0 V versus reversible hydrogen electrode, which is superior to the reported 2D covalent organic frameworks and most carbon nitride materials (0.09–6.0 µA cm?2). Density functional theory calculations identify the thiophene units and cyano substituents at the vinylene linkage as active sites for the evolution of H2. 相似文献
Organic spin valves (OSVs) have become an essential building block of next‐generation memory devices which focus on spin degree of transporting carriers. Meanwhile, negative magnetoresistance (MR) effect in the OSV devices is increasingly observed which deserves further exploration for the rich spin physics behind. In this work, the negative MR response in ferromagnetic (FM) metal‐based OSVs using donor−acceptor (D−A) conjugated polymer based on the naphthalenediimide units as a spacer material is observed. The negative MR effect does not result from negative polarization at spin injection and detection interface as well as tunneling anisotropic magnetoresistance effect, but from the spin transport inside the D−A polymer spacer. Even the stacking sequence of the spin injection and detection electrodes is reversed or changed the polymer coating solvents, the D−A polymer contributed negative MR response still can be observed. For further identifying negative MR origin, the bottom FM metal polarizer is replaced into high‐polarization La0.7Sr0.3MnO3 thin film, negative MR feature is well reproduced. Based on these points, it is deduced that the spin‐orientation reversal inside D−A polymer spacer is the ultimate reason for such negative MR response. The filtering‐like spin reversal activity is also in positive proportion to intermolecular interaction. 相似文献
The synthesis of a novel naphthalenediimide (NDI)‐bithiazole (Tz2)‐based polymer [P(NDI2OD‐Tz2)] is reported, and structural, thin‐film morphological, as well as charge transport and thermoelectric properties are compared to the parent and widely investigated NDI‐bithiophene (T2) polymer [P(NDI2OD‐T2)]. Since the steric repulsions in Tz2 are far lower than in T2, P(NDI2OD‐Tz2) exhibits a more planar and rigid backbone, enhancing π–π chain stacking and intermolecular interactions. In addition, the electron‐deficient nature of Tz2 enhances the polymer electron affinity, thus reducing the polymer donor–acceptor character. When n‐doped with amines, P(NDI2OD‐Tz2) achieves electrical conductivity (≈0.1 S cm?1) and a power factor (1.5 µW m?1 K?2) far greater than those of P(NDI2OD‐T2) (0.003 S cm?1 and 0.012 µW m?1 K?2, respectively). These results demonstrate that planarized NDI‐based polymers with reduced donor–acceptor character can achieve substantial electrical conductivity and thermoelectric response. 相似文献
Charge‐transfer materials based on the self‐assembly of aromatic donor–acceptor complexes enable a modular organic‐synthetic approach to develop and fine‐tune electronic and optical properties, and thus these material systems stand to impact a wide range of technologies. Through laser‐induction of temperature gradients, in this study, user‐defined patterning of strongly dichroic and piezoelectric organic thin films composed of donor–acceptor columnar liquid crystals is shown. Fine, reversible control over isotropic versus anisotropic regions in thin films is demonstrated, enabling noncontact writing/rewriting of micropolarizers, bar codes, and charge‐transfer based devices. 相似文献
Supercapacitors have received increasing interest as energy storage devices due to their rapid charge–discharge rates, high power densities, and high durability. In this work, novel conjugated microporous polymer (CMP) networks are presented for supercapacitor energy storage, namely 3D polyaminoanthraquinone (PAQ) networks synthesized via Buchwald–Hartwig coupling between 2,6‐diaminoanthraquinone and aryl bromides. PAQs exhibit surface areas up to 600 m2 g?1, good dispersibility in polar solvents, and can be processed to flexible electrodes. The PAQs exhibit a three‐electrode specific capacitance of 576 F g?1 in 0.5 m H2SO4 at a current of 1 A g?1 retaining 80–85% capacitances and nearly 100% Coulombic efficiencies (95–98%) upon 6000 cycles at a current density of 2 A g?1. Asymmetric two‐electrode supercapacitors assembled by PAQs show a capacitance of 168 F g?1 of total electrode materials, an energy density of 60 Wh kg?1 at a power density of 1300 W kg?1, and a wide working potential window (0–1.6 V). The asymmetric supercapacitors show Coulombic efficiencies up to 97% and can retain 95.5% of initial capacitance undergo 2000 cycles. This work thus presents novel promising CMP networks for charge energy storage. 相似文献
All‐polymer solar cells (all‐PSCs) based on n‐ and p‐type polymers have emerged as promising alternatives to fullerene‐based solar cells due to their unique advantages such as good chemical and electronic adjustability, and better thermal and photochemical stabilities. Rapid advances have been made in the development of n‐type polymers consisting of various electron acceptor units for all‐PSCs. So far, more than 200 n‐type polymer acceptors have been reported. In the last seven years, the power conversion efficiency (PCE) of all‐PSCs rapidly increased and has now surpassed 10%, meaning they are approaching the performance of state‐of‐the‐art solar cells using fullerene derivatives as acceptors. This review discusses the design criteria, synthesis, and structure–property relationships of n‐type polymers that have been used in all‐PSCs. Additionally, it highlights the recent progress toward photovoltaic performance enhancement of binary, ternary, and tandem all‐PSCs. Finally, the challenges and prospects for further development of all‐PSCs are briefly considered. 相似文献
The design of hydrogen storage materials is one of the principal challenges that must be met before the development of a hydrogen economy. While hydrogen has a large specific energy, its volumetric energy density is so low as to require development of materials that can store and release it when needed. While much of the research on hydrogen storage focuses on metal hydrides, these materials are currently limited by slow kinetics and energy inefficiency. Nanostructured materials with high surface areas are actively being developed as another option. These materials avoid some of the kinetic and thermodynamic drawbacks of metal hydrides and other reactive methods of storing hydrogen. In this work, progress towards hydrogen storage with nanoporous materials in general and porous organic polymers in particular is critically reviewed. Mechanisms of formation for crosslinked polymers, hypercrosslinked polymers, polymers of intrinsic microporosity, and covalent organic frameworks are discussed. Strategies for controlling hydrogen storage capacity and adsorption enthalpy via manipulation of surface area, pore size, and pore volume are discussed in detail.
Layers of naturally occurring clay minerals are rearranged to prepare highly sensitive multiresponsive clay–clay bilayer membrane (CCBM). The CCBM introduced here responds to the minuscule changes in the surrounding environments including temperature, humidity, and presence of solvent vapors by morphing in specific manners. Strips cut from CCBM exhibit up to 588 N kg?1 force output when exposed to temperature fluctuations. Inheriting the natural stability of clay minerals, CCBM demonstrates extreme robustness, heating up to 500 °C, cooling with liquid N2 and exposure to corrosive chemical vapors did not deteriorate its bending performance. Mechanistic studies suggest that shape transformations of CCBM are driven by the unequal response of its components to external stimuli. 相似文献
下载免费PDF全文