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New π-conjugated polymers based on dithienyl-diketopyrrolopyrrole (dtDPP) were synthesized by direct arylation polymerization, that is, poly(dtDPP), poly(dtDPP-FL), and poly(dtDPP-TPA). They reveal...

A ternary blend, wherein a tertiary acceptor is incorporated into a donor:non-fullerene acceptor (NFA) binary blend has emerged as a promising strategy for improving power conversion efficiency and stability of organic bulk heterojunction photovoltaics (OPVs). However, the effects of the tertiary component remain elusive due to the complex variation of crystallinity and morphology of donor and acceptor phases during thermal annealing. Herein a combination of in situ transmission electron microscopy and X-ray diffraction spectroscopy utilized during annealing identifies that (1) the addition of the tertiary component (O-IDFBR) delays the glass transition temperature of edge-on-oriented polymer donor (P3HT), prohibits the glass transition of face-on-oriented polymer donor (P3HT), broadens the crystallization temperature of O-IDTBR, and enhances the overall crystallinity of the donor and acceptor phases (P3HT and O-IDTBR), and (2) the ternary component induces homogeneously distributed nanoscale domains rather than a microscale separation between the donor and acceptor as observed in the binary blend. The optimized nanoscale domain morphology, driven by slower crystallization and enhanced overall crystallinity leads to a more stable morphology, resulting in superior device performance and stability.

The various proteins and asymmetric lipid bilayers present in cell membranes form curvatures, resulting in structural transformations to generate vesicles. Fission and fusion processes between vesicles and cell membranes are reversible in living organisms. Although the transformation of a two-dimensional membrane to a three-dimensional vesicle structure is a common natural phenomenon, the lack of a detailed understanding at the molecular level limits the development of synthetic systems for functional materials. Herein, we report a supramolecular membrane system through donor-acceptor interactions using a π-deficient acceptor and π-rich donor as building blocks. The reduced electrostatic repulsion between ammonium cations and the spontaneously deprotonated neutral amino group induced anisotropic membrane curvature, resulting in membrane fission to form vesicles with a detailed understanding at the molecular level. Furthermore, the reversible transformation of vesicles to membranes upon changing the pH provides a novel synthetic system exhibiting both fission and fusion processes.

Π-conjugated polymers (π-CPs) blended with ionic liquids (ILs) have shown great potential for noninvasive diagnostics by transducing dielectric environmental changes induced by volatile organic com...

Reported here is a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a sixfold nucleophilic substitution with cyanide on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification significantly impacted the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge‐carrier mobility of up to μ e≈0.15 cm2 V−1 s−1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach., A new strongly electron‐accepting end group, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT), has been prepared by a one‐step sixfold nucleophilic substitution reaction. Cyanation results in a significant enhancement of the electron affinity in comparison to the fluorinated analogue, and the material demonstrates promising n‐type performance in solution processed organic field‐effect transistors with excellent stability.

Rapid and selective removal of micropollutants from water is important for the reuse of water resources. Despite hollow frameworks with specific functionalized porous walls for the selective adsorption based on a series of interactions, tailoring a stable shape of nanometer- and micrometer-sized architectures for the removal of specific pollutants remains a challenge. Here, exactly controlled sheets, tubes, and spherical frameworks were presented from the crosslinking of supramolecular colloids in polar solvents. The frameworks strongly depended on the architecture of original supramolecular colloids. As the entropy of colloids increased, the initial laminar framework rolled up into hollow tubules, and then further curled into hollow spheres. These shape-persistent frameworks showed unprecedented selectivity as well as specific recognition for the shape of pollutants, thus contributing to efficient pollutant separation.

Despite recent breakthroughs in the fabrication of spin-coated small-area devices (≤0.1 cm2) with power conversion efficiencies (PCEs) of more than 17%, printed large-area organic solar cells (OSCs) are significantly less efficient because of the intrinsic differences between the coating dynamics of the two types of OSCs. The PCEs of printed large-area (∼100 cm2) OSCs have typically been decreased compared with those of small-area spin-coated devices. In this work, an efficient low-temperature printing method to fabricate high-efficiency large-area nonfullerene-based OSC modules is successfully demonstrated. A systematic study of the relationship between the concentration of the photoactive solution and the resulting film properties reveals that the large-area modules (85 cm2) produced in this work deliver excellent performance, yielding PCEs of up to 8.18% with a geometric fill factor of 85%. These novel OSC modules are ∼87% as efficient as small-area printed single cells (cell PCE ∼9.43% with 1 cm2).

Although considerable effort in recent years has been devoted to the development of two-dimensional nanostructures, single-layered chiral sheet structures with a lateral assembly of discrete clusters remain elusive. Here, we report single-layered chiral 2D sheet structures with dual chiral void spaces in which discrete clusters of planar aromatic segments are arranged with in-plane AB order in aqueous methanol solution. The chirality of the sheet is induced by the slipped-cofacial stacks of rectangular plate-like aromatic segments in the discrete clusters which are arranged laterally with up and down packing, resulting in dual chiral void spaces. The chiral nanosheets function as superfast enantiomer separation nanomaterials, which rapidly absorb a single enantiomer from a racemic mixture with greater than 99 % ee.

Although considerable effort in recent years has been devoted to the development of two-dimensional nanostructures, single-layered chiral sheet structures with a lateral assembly of discrete clusters remain elusive. Here, we report single-layered chiral 2D sheet structures with dual chiral void spaces in which discrete clusters of planar aromatic segments are arranged with in-plane AB order in aqueous methanol solution. The chirality of the sheet is induced by the slipped-cofacial stacks of rectangular plate-like aromatic segments in the discrete clusters which are arranged laterally with up and down packing, resulting in dual chiral void spaces. The chiral nanosheets function as superfast enantiomer separation nanomaterials, which rapidly absorb a single enantiomer from a racemic mixture with greater than 99 % ee.

Semiconducting polymers with oligoethylene glycol sidechains have attracted strong research interest for organic electrochemical transistor (OECT) applications. However, key molecular design rules for high-performance OECTs via efficient mixed electronic/ionic charge transport are still unclear. Herein, we synthesize and characterize new glycolated copolymers (gDPP-TTT and gDPP-TTVTT) with diketopyrrolopyrrole (DPP) acceptor and thiophene-based (TTT or TTVTT) donor units for accumulation mode OECTs, where a long-alkyl-group (C12 ) attached to DPP unit acts as a spacer distancing the oligoethylene glycol from the polymer backbone. gDPP-TTVTT shows the highest OECT transconductance (61.9 S cm-1 ) and high operational stability, compared to gDPP-TTT and their alkylated counterparts. Surprisingly, gDPP-TTVTT also shows high electronic charge mobility in field-effect transistor, suggesting efficient ion injection/diffusion without hindering its efficient electronic charge transport. The elongated donor unit (TTVTT) facilitates the hole polaron formation more localized to the donor unit, leading to faster and easier polaron formation with less impact on polymer structure during OECT operation, as opposed to the TTT unit. This is supported by molecular dynamics (MD) simulation. We conclude that these simultaneously high electronic and ionic charge transport properties are achieved due to the long-alkyl-group spacer in amphipathic sidechains, providing an important molecular design rule for glycolated copolymers. This article is protected by copyright. All rights reserved.

Emerging organic solar cells based on a ternary strategy is one of the most effective methods for improving the blend film morphology, absorption ability, and device performances. On the other hand, this strategy has had very limited success in all-polymer solar cells (all-PSCs) because of the scarcity of new polymers and the challenges faced during third component optimization. Herein, highly efficient ternary all-PSCs were developed from siloxane-functionalized side chains with a wide-band-gap (

Suppressing nonradiative recombination at the interface between the organometal halide perovskite (PVK) and the charge-transport layer (CTL) is crucial for improving the efficiency and stability of PVK-based solar cells (PSCs). Here, a new bathocuproine (BCP)-based nonconjugated polyelectrolyte (poly-BCP) is synthesized and this is introduced as a "dual-side passivation layer" between the tin oxide (SnO

Macrocyclic structures are challenging synthetic targets owing to various potential applications ranging from drug discovery to nanomaterials. Their use, however, is highly limited due to synthetic difficulties arising from an entropic penalty for folding of linear chains. Here, we report single-layered porous nanosheets with 2D ordered internal cavities that act as a highly efficient macrocycle generator, changing linear substrates to release as macrocycles in aqueous methanol solution. The nanosheets with hydrophobic cavities encapsulate a linear substrate with nearly perfect uptake, perform clean cyclization, and then spontaneously release as a pure macrocycle. The self-separation of the macrocycle that precipitates from the solution leads to repeated cycles of macrocycle generation; thereby, the single-layered porous materials enabling catch and release offer a powerful novel strategy for repeated macrocycle generation.

Recent breakthroughs in molecular design have allowed for remarkable achievement in the field of non-fullerene acceptor (NFA)-based organic solar cells (OSCs) with high power conversion efficiencies (PCEs) of over 15%. However, despite such promising advances, the inferior stability of OSCs under operating conditions remains a prominent challenge that must be overcome for their practical realization. Here, versatile ternary photoactive systems with simultaneously enhanced efficiency and photostability are developed by introducing a small amount of fullerene (PC71BM) into a narrow band gap NFA-based bulk heterojunction nanocomposite (PTB7-Th:IEICO-4F); this approach leads to an enhanced PCE of 10.55% and a prolonged lifetime, retaining approximately 80% of the initial PCE after 500 h of operation under continuous illumination. Based on the energy levels and surface energies of the component materials, cascade energetic alignment facilitates electron transfer without trapping. The PTB7-Th/PC71BM interface provides an energy barrier to suppress recombination between holes in PTB7-Th and electrons in IEICO-4F. Moreover, a small amount of PC71BM promotes favorable molecular packing and orientation of IEICO-4F, leading to enhanced electron mobility and balanced charge transport. A study using transient absorption spectroscopy reveals that the ternary blend effectively suppresses the evolution of charge recombination.

‘Sol–gel’-processed transition metal oxide (TMO) thin films sandwiched by an organic photoactive layer and metal electrodes have proven to be a versatile interlayer for photovoltaics with long-term stability on the laboratory scale; however, chemical defects and dewetting (or shrinkage) processes during sol–gel synthesis on top of the photoactive layer often cause performance variations, impeding the development of large-area photovoltaic modules. Here, we demonstrate that a low surface energy difference at the organic interface allows long-range diffusion of metal ion precursors to promote continuous chemical synthesis associated with oxo-bridge formation. Using high-resolution Auger electron spectroscopy, we confirm that the resultant TMO thin film on top of the suitable surface has a defect-free and continuous metal–oxygen network (MON) with a high oxygen/metal ratio. Our findings can be applied to obtain organic/perovskite photovoltaic modules having long-term stability, approaching an efficiency of 4.2%/14.5% and maintaining over 80% of their initial efficiency for up to 1500 hours/2000 hours with an area of 10.8 cm2/9.06 cm2.

A series of cyclic poly(e-caprolactone)s (c-PCLs) with extremely high purity have been prepared and quantitatively investigated in terms of the impact of molecular topology on the nanoscale film morphological structure. Quantitative synchrotron grazing incidence small angle X-ray scattering analysis found that c-PCLs, in comparison with their linear counterparts (l-PCLs), exclusively form a horizontal lamellar structure with a shorter long period, characterized by a thicker crystalline layer, thicker and denser interfacial layers and a thinner amorphous layer. Grazing incidence wide angle scattering analysis additionally confirmed higher crystallinities for c-PCLs, which were further supported by synchrotron X-ray reflectivity analysis. Overall, the quantitative structural analyses of this study provide for the first time comprehensive insights into cyclic topology effects on the nanoscale film morphology of biocompatible and environment-friendly PCL.

A tubular MOF with adequate active sites is prepared by the bending of metal-coordinated honeycombed frameworks via titration and shows fast catalytic kinetics with lower catalytic loading for CO2 conversion. The TON is observed to be 2300 and the corresponding TOF of up to 173 h-1 is achieved for the first time.

Printable organic sensors fabricated from solution-processed π-conjugated polymers (π-CPs) are promising candidates to detect volatile organic compounds (VOCs) due to the intriguing physical, chemical and electronic properties of π-CPs. These devices, often termed organic chemiresistors, require good sensing capabilities to transduce stimuli from specific VOCs at low concentrations into analytical electric signals. However, discriminating such VOCs using organic chemiresistors has proven very challenging. Herein, we report that the molecular-level electrochemical doping of π-CPs with solid-state ionic liquids (SILs) significantly improves their electrical conductivity (∼10−1 S cm−1) and selective VOC interactions, which can be manipulated through different π-CPs:SIL blend ratios. These characteristics enable the fine discrimination of VOCs at concentrations in the parts-per-billion (ppb) range under low power consumption (

We report that a chemically p-doped conjugated small-molecule electrolyte (CSE) can be used as a strong and uniform dipole array for highly efficient optoelectronic devices via electrostatically in...

In this study, poly(δ-valerolactone) (PVL) axles bearing movable and ionically fixed rotaxane wheels linked with polystyrene (rot-PS-M and rot-PS-F) have been investigated for the first time in the...

A molecular-level understanding of ion and polymer dynamics in imidazolium–poly(ethylene glycol) (PEG) copolyester ionomers having different counteranions [PF6– vs (CF3SO2)2N–], alkylene spacer len...

Metal-air batteries as alternatives to the existing lithium-ion battery are becoming increasingly attractive sources of power due to their high energy-cost competitiveness and inherent safety; however, their low oxygen evolution and reduction reaction (OER/ORR) performance and poor operational stability must be overcome prior to commercialization. Herein, it is demonstrated that a novel class of hydrothermally grown dual-phase heterogeneous electrocatalysts, in which silver-manganese (AgMn) heterometal nanoparticles are anchored on top of 2D nanosheet-like nickel vanadium oxide (NiV

High efficiency and nonhalogenated solvent processing are important issues for commercial application of all-polymer solar cells (all-PSCs). In this regard, we increased the photovoltaic performance of all-PSCs to a benchmark power conversion efficiency (PCE) of 11.66% by manipulating the pre-aggregation of a new π-conjugated polymer donor (Nap-SiBTz) using toluene as a solvent. This use of Nap-SiBTz enhanced the absorption coefficient (λmax = 9.30 × 104 cm-1), increased charge carrier mobility, suppressed trap-assisted recombination, improved bulk heterojunction morphology, and resulted in high PCEs of all-PSCs with an active layer thickness of 200 nm. To overcome severe charge recombination and energy losses, a 1-phenylnapthalene additive was used to achieve a well-ordered microstructure and molecular packing that inherently improved the device performances. The resulting encapsulation-free devices exhibited good ambient and thermal stabilities. The results of this study augur well for the future of the roll-to-roll production of all-PSCs.

Long-term stability of organic blends is a key factor for the practical use of organic solar cells (OSCs) in commercial fields. Here, we report the strategic incorporation of non-fullerene small molecules in polymer:fullerene blends to obtain ternary OSCs with improved efficiency and extended lifetimes. Non-fullerene small molecules employed in the polymer:fullerene blend successfully increased the photon-to-current conversion process as an efficient charge cascade acceptor. A combination of theoretical simulations and experimental measurements revealed that aggregation of meta-stable fullerene molecules was significantly alleviated in the ternary blend, thereby preventing an unintentional increase in the threshold for charge transfer during operation. Thus, the ternary OSCs could exhibit highly extended lifetimes with improved morphological stability and better resistance to performance decay under harsh real operational conditions compared to their binary counterparts. Combined with its high efficiency and improved device lifetimes, the high tolerance to the ternary blend thickness offers promise for commercially acceptable ternary OSCs fabricated by a printing process.

Chemical and electronic sensitization in metal oxide gas sensors are severely limited by poor dimension controls of metal oxide nanostructure and their electric/electronic properties. These limitations are overcome using hydrothermal-induced heterointerface engineering approaches. This work demonstrates that forming spherical titanium dioxide nanoparticles on a substrate significantly reduce a surface energy barrier of nucleation and induces novel mesophorous hierarchical TiO2 structure during hydrothermal synthesis, consequently increasing the surface area of the structure by ∼ 3 times compared to that of control. In addition, we succeeded in tailoring the energetics of hierarchical TiO2 nanosctructure by decorating with the nickel oxide and silver nanoparticles, which results in a desirable semiconductors/metal heterointerface for fast charge transfer where silver nanoparticles bridge nickel oxide and TiO2 nanostructure, and silver nanoparticles serve as preferential sites for chemisorption and migration of oxygen anions. The resulting heterostructure sensing properties such as sensitivity, limit of detection and selectivity are studied as a function of operating temperature (30–150 °C), relative humidity (RH) and various volatile organic analytes concentrations. The TiO2/Ag/NiO heterostructure finally exhibits a high gas response of ∼ 2.1 for acetone with a limit of detection of 34 ppb at 30 °C (or 21 ppb at 90 °C), and retains an excellent selectivity of acetone even at 90 % relative humidity. It exhibited a highly stable and speedy gas response for acetone toward various gases such as formaldehyde, ethanol, hydrogen sulfide, carbon monoxide even operating at 90 °C. Our results suggest a potential of constructed TiO2/Ag/NiO heterostructure for superior sensing volatile organic acetone and will also stimulate research on hetero-structured gas sensors with high sensitivity and selectivity.

Soluble aromatic polyimides and polyvinyls were prepared by incorporating pyridine moiety and its derivatives in the backbone and the side groups, respectively: 6F-Py-i polymers based on the polyimide backbone (6F-Py-1 to 6F-Py-7) and PVPy-i polymers based on the polyvinyl backbone (PVPy-1 to PVPy-4). All polymers were found to be amorphous. The 6F-Py-i polymers were thermally stable up to 511–545 °C; the PVPy-i polymers were stable up to 362–376 °C. Their glass transitions, thin film densities, molecular orbitals, and band gaps were determined. The electrical devices fabricated with the polymers in an electrode/polymer/electrode structure revealed p-type unipolar write-once-read-many times (namely, permanent) or dynamic random access memory or dielectric behavior, depending on the substituents of the pyridine unit and the film thicknesses. In particular, such digital memory characteristics were found to originate from the pyridine moieties possessing a high charge affinity in the polymers. However, the pyridine moieties were found to still need at least two or more aromatic substituents to get enough power to stabilize charges via utilizing the resonance effects provided by the substituents. Overall, this study demonstrated that the pyridine unit conjugated with two or more aromatic substituents is a very useful component to design and synthesize digital memory materials based on thermally stable polyimides and other high performance polymers. The 6F-Py-i polymers have potential for the low-cost mass production of high-performance programmable unipolar permanent memory devices with very low power consumption.

Protein pores are highly specific in binding to chiral substrates and in catalysing stereospecific reactions, because their active pockets are asymmetric and stereoselective1,2. Chiral binding materials from molecular-level pores with high specificity have not been achieved because of problems with pore deformation and blocking 3 . A promising solution is the self-assembly of single sheets where all pores are exposed to the environment, for example as metal-organic frameworks 4 , polymers5,6 or non-covalent aromatic networks7-10, but, typically, the pores are distant from the internal cavities with chirality. Here, we report the synthesis of homochiral porous nanosheets achieved by the 2D self-assembly of non-chiral macrocycles, with open/closed pore switching. Pore chirality is spontaneously induced by a twisted stack of dimeric macrocycles. The porous 2D structures can serve as enantiomer sieving membranes that exclusively capture a single enantiomer in a racemic mixture solution, with uptake capacity greater than 96%. Moreover, the entrapped guests inside the pores can be pumped out by pore closing triggered by external stimuli. This strategy could provide new opportunities for controlled molecule release, as well as for artificial cells.

Although substantial progress has been made at increasing power conversion efficiencies (PCEs) the field of ternary organic solar cells (TOSCs) during the past few years, choice of π-conjugated polymers that exhibit strong complementary spectra and achieve high photovoltaic parameters (open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and PCE) simultaneously is limited. In this paper, TOSCs demonstrated a high PCE of 17.09% based on a π-conjugated polymer (named SiCl-BDT, bandgap ≈ 1.84 eV) as a third component (15 wt%) to the host binary system consisting of a PM7:Y7. The third component was used to achieve enhanced absorption coefficient (λmax = 5.5 × 104 cm−1) and more balanced charge carrier transport, frontier molecular orbital (FMO) energy levels, and blend miscibility, contributed to an improved FF of 70.38% and yielded an impressive Jsc of 27.37 mA/cm2 and Voc of 0.84 V. The PCE was higher than the host PM7:Y7 (15.13%) binary device. In addition, we found the photovoltaic performance of TOSCs could be further increased to a benchmark PCE of 17.40% using an interface engineering strategy. Thus, enables efficient charge transfer in TOSCs compared with that of without interlayer TOSCs, leading to high Jsc, Voc. The resulting encapsulation-free TOSCs showed excellent ambient and thermal stability. Accordingly, this work suggests that the use of a passivated electron transporting layer (ETL) and a π-conjugated polymer as a third component offers a promising means of overcoming the lower PCEs of OSCs.

Despite recent advances in the use of porous materials as efficient heterogeneous catalysts which operate through effectively trapping reagents in a well-defined space, continuously uptaking reagents to substitute products in the cavity for efficient product turnover still remains challenging. Here, a porous catalyst is endowed with ‘breathing’ characteristics by thermal stimulus, which can enable the efficient exchange of reagents and products through reversible stacking from inflated aromatic hexamers to contracted trimeric macrocycles. The contracted super-hydrophobic tubular interior with pyridine environment exhibits catalytic activity towards a nucleophilic aromatic substitution reaction by promoting interactions between concentrated reagents and active sites. Subsequent expansion facilitates the exchange of products and reagents, which ensures the next reaction. The strategy of mesoporous modification with inflatable transition may provide a new insight for construction of dynamic catalysts. Porous materials are efficient heterogeneous catalysts, but the continuous uptake of reagents to substitute products in the cavities remains unsettled. Here the authors fabricate a self-assembled tubular structure with breathing characteristics for efficient exchange of reactants and products in a nucleophilic substitution reaction.

Organic semiconductors (OSCs) are highly susceptible to the formation of metastable polymorphs that are often transformed by external stimuli. However, thermally reversible transformations in OSCs with stability have not been achieved due to weak van der Waals forces, and poor phase homogeneity and crystallinity. Here, a polymorph of a single crystalline 2,7-dioctyl[1] benzothieno[3,2-b][1]benzothio-phene rod on a low molecular weight poly(methyl methacrylate) (≈120k) that limits crystal coarsening during solvent vapor annealing is fabricated. Molecules in the polymorph lie down slightly toward the substrate compared to the equilibrium state, inducing an order of greater resistivity. During thermal cycling, the polymorph exhibits a reversible change in resistivity by 5.5 orders with hysteresis; this transition is stable toward bias and thermal cycling. Remarkably, varying cycling temperatures leads to diverse resistivities near room temperature, important for nonvolatile multivalue memories. These trends persist in the carrier mobility and on/off ratio of the polymorph field-effect transistor. A combination of in situ grazing incident wide angle X-ray scattering analyses, visualization for electronic and structural analysis simulations, and density functional theory calculations reveals that molecular tilt governs the charge transport characteristics; the polymorph transforms as molecules tilt, and thereby, only a homogeneous single-crystalline phase appears at each temperature.