Ultrasound-Induced Organogel Formation Followed by Thin Film Fabrication via Simple Doctor Blading Technique for Field-Effect Transistor Applications

Preparation of a novel Bi9O7.5S6/SnS composite film with improved photoelectric properties

Atomically thin two-dimensional (2D) bismuth oxychalcogenides have been considered as promising candidates for high-speed and low-power photoelectronic devices due to their high charge carrier mobility and excellent environmental stability. However, the photoelectric performance of their bulk materials still falls short of expectations. Herein, a novel Bi9O7.5S6/SnS composite film with a type-II heterojunction was successfully prepared by combining hydrothermal and knife-coating techniques. The crystal structure, morphology, and optical properties were systematically investigated. Under 1 V bias voltage, the photocurrent of the Bi9O7.5S6/SnS composite film can be obtained as 107 μA cm-2, which is about 29.9 times and 93.9 times higher than that of bare Bi9O7.5S6 and SnS, respectively. The type-II heterojunction has played a significant role in improving the photoelectric performance of the Bi9O7.5S6/SnS composite film by facilitating the separation and transfer of photo-generated carriers. This work sheds light on the design and development of new bismuth-based composite materials for advanced photoelectric and photocatalytic applications.

Self-Assembly of a Series of Carbazole-Based Vinyl-benzoxazole Derivatives in Gel Phases

A series of carbazole-based vinyl-benzoxazole derivatives have been synthesized in order to verify whether X-ray diffraction (XRD) simulation can give more information about intermolecular stacking in the gel phase. It was found that their gelation capabilities were strongly dependent on the length of the alkyl chain. The compounds with shorter alkyl chains have lower critical gelation concentrations (CGCs) in nonpolar alkane and alcohols with longer carbon chains. On the other hand, compounds with long alkyl chains presented small CGCs in polar methanol. Powder XRD structure solution gave more information about intermolecular stacking than the traditional way of analyzing diffraction peaks to derive approximate molecular stacking patterns. The results verified that gelators had a similar head-to-tail π-stacking between aromatic groups in gel phases although different slipping angles existed. Moreover, ordered stacking between the alkyl chains was also present.

Nanoconfinement-Guided Construction of Nanozymes for Determining H2 O2 Produced by Sonication

Nanomaterials with enzyme-like activities, termed as nanozymes, have found wide applications in various fields. It has been a long-term aim to rationally design and synthesize highly active nanozymes and thus to further improve their application performance. Guided by the nanoconfinement effect, we confine cytochrome c (Cyt c) within a mesoporous metal-organic framework (MOF), PCN-222 nanoparticle (NP), forming a protein/MOF hybrid nanozyme, termed as Cyt c@PCN-222 NP. The confined Cyt c exhibits around 3-4-fold higher peroxidase-like activity than free Cyt c. Due to the increase in the activity of Cyt c, the Cyt c@PCN-222 NPs exhibit a quite low limit of detection (≈0.13 μM) towards H₂ O₂ . Sonication-induced H₂ O₂ formation in water by using a lab-quipped ultrasonic cleaner can be sensitively probed, which suggests that H₂ O₂ -sensitive materials should be carefully handled during the utilization of ultrasonic equipment. We speculate that this nanoconfinement strategy can broaden our synthetic methodology for the rational design of nanozymes.

Self-Assembled Copper Metallogel Bearing Terpyridine and Its Application as a Catalyst for the Click Reaction in Water

Metallogels have attracted a great deal of interest because of their intriguing properties and applications in chemsensors, batteries, catalysis, and other fields. In this work, a novel ligand bearing terpyridine and hydroxyamine units was designed and synthesized. The ligand selectively gelated with copper ions in water by heating and cooling or sonication. Different physicochemical studies [Fourier transform infrared, ultraviolet-visible (UV-vis), electron paramagnetic resonance (EPR), scanning electron microscopy, X-ray diffraction, and rheology] were conducted to characterize the gels. We show that coordination interaction, π-π interaction, and noncovalent interaction had obvious effects on the properties of the gel. Additionally, a stable radical hydrogel could be obtained by ultrasound treatment, which was accompanied by color variation from green to blue. This was further confirmed by UV-vis and EPR experiments. Furthermore, the copper metallogels were developed as catalysts for the preparation of 1,2,3-triazole derivatives in water at 25 °C. Although various types of catalysts have been investigated, the use of metallogels as catalysts for the click reaction in water has been scarce. This strategy shows the process is simple, affords a high yield, and is "green" and economical.

Molecular nanoribbon gels

Herein, we show that twisted molecular nanoribbons with as many as 322 atoms in the aromatic core are efficient gelators capable of self-assembling into ordered π-gels with morphologies and sol–gel transitions that vary with the length of the nanoribbon. In addition, the nanoribbon gels show a red fluorescence and also pseudoconductivity values in the same range as current state-of-the-art π-gels.

Herein, we show that twisted molecular nanoribbons with as many as 322 atoms in the aromatic core are efficient gelators capable of self-assembling into ordered π-gels with morphologies and sol–gel transitions that vary with the length of the nanoribbon.

Sustainable Approaches to the Synthesis of Metallophthalocyanines in Solution

This work aims to investigate more sustainable reaction conditions for the synthesis of metallophthalocyanines. Anisole, glycerol and their mixtures have been investigated as reaction media for the tetramerization of phthalonitriles. Acetates of three divalent first-transition metal cations, Co(II), Cu(II) and Zn(II), were used and several bases were tested, depending on the chosen substrates and reaction conditions, with a view to making the whole process more sustainable while ensuring its scalability. Unsubstituted phthalocyanines were synthesized to analyze the behavior of the different metal ions in terms of reactivity in the new reaction media, resulting in a general Cu > Co > Zn trend, while the nonpolar tetra-tert-butyl substitution was investigated to evaluate the synthesis of soluble derivatives in the new conditions. Furthermore, the potassium hydroxide (KOH)-aided statistical synthesis of the unsymmetrical 9(10), 16(17), 23(24)-tri-tert-butyl-2-iodophthalocyaninato zinc(II), starting from 4-tert-butylphthalonitrile and 4-iodophthalonitrile in a glycerol/anisole mixture, proceeded with a satisfactory 26% yield. Our results provide insights into the investigation of new reaction environments and the understanding of their strengths and weaknesses, with a view to further increasing the sustainability of the synthesis of metallomacrocycles with high added value while lowering their production cost.

Rapid and facile method to prepare oxide precursor solution by using sonochemistry technology for WZTO thin film transistors

In this paper, a rapid and facile method of preparing metal-oxide semiconductor precursor solution using sonochemistry technology is proposed. Compared with the traditional method (water bath above 60 °C for several hours), the efficiency of preparing solution is improved, because sonochemical reaction is found to accelerate the dissolution of solutes and the agitation of solution. The color comparison and thermal gravimetric and differential scanning calorimetry of solution confirme the formation of W-doped zinc tin oxide (WZTO) precursor solution with good performance. The effects of sonochemical reactions on the film structure, surface morphology, optical properties and chemical composition of WZTO thin films are analyzed by atomic force microscopy, X-ray diffraction, UV visible spectrum and X-ray photoelectron spectroscopy. The results show that the film has a smooth surface, an amorphous structure, a high transmittance and more M-O bonding. Hence, a rapid process of preparing WZTO solution (sonochemical treatment for 10 min) and fabricate TFT with high electron mobility (2.7 cm² V^-1 s^-1) is established, while the corresponding mobility of the traditional method is 1.2 cm² V^-1 s^-1. The results show that the sonochemical reaction can improve the efficiency of preparing solution by 1800% and it is a fast and efficient method for preparing precursor solutions.

Bionic composite hydrogel with a hybrid covalent/noncovalent network promoting phenotypic maintenance of hyaline cartilage

A novel injectable bionic hydrogel with hybrid covalent/noncovalent network derived from covalent conjugation of HA-SH and noncovalent supramolecular self-assembly of BPAA-AFF-OH short peptide is fabricated.

Functional Supramolecular Gels Based on the Hierarchical Assembly of Porphyrins and Phthalocyanines

Supramolecular gels containing porphyrins and phthalocyanines motifs are attracting increased interests in a wide range of research areas. Based on the supramolecular gels systems, porphyrin or phthalocyanines can form assemblies with plentiful nanostructures, dynamic, and stimuli-responsive properties. And these π-conjugated molecular building blocks also afford supramolecular gels with many new features, depending on their photochemical and electrochemical characteristics. As one of the most characteristic models, the supramolecular chirality of these soft matters was investigated. Notably, the application of supramolecular gels containing porphyrins and phthalocyanines has been developed in the field of catalysis, molecular sensing, biological imaging, drug delivery and photodynamic therapy. And some photoelectric devices were also fabricated depending on the gelation of porphyrins or phthalocyanines. This paper presents an overview of the progress achieved in this issue along with some perspectives for further advances.

Covalent Cross-Linking of Diketopyrrolopyrrole-Based Organogels with Polydiacetylenes

A new strategy toward functional materials with novel properties and well-defined structures has been developed through the topochemical polymerization of diacetylene-containing diketopyrrolopyrrole (DPP) derivatives. In order to enable the efficient photopolymerization and cross-linking of the materials, a rational design of DPP-based derivatives has been performed to incorporate amide moieties, thus enabling the formation of intermolecular hydrogen bonds and the formation of an organogel. The new materials showed good gelation properties in aromatic solvents, resulting in the formation of a dense fibrous network in the gel state. Upon UV irradiation, the supramolecular self-assemblies obtained were shown to be efficiently cross-linked through the conversion of diacetylene into polydiacetylene. A detailed investigation of new resulting materials was performed by a combination of morphological characterization tools, including X-ray diffraction, Raman spectroscopy, and atomic force microscopy. Our results demonstrate that the topochemical polymerization of diacetylene-containing DPP-based compounds is a promising strategy toward new electroactive and well-defined materials, without the use of catalysts or additives, thus creating new opportunities for the preparation and processing of π-conjugated materials.

Short Oligopeptides for Biocompatible and Biodegradable Supramolecular Hydrogels

Short Phe-rich oligopeptides, consisting of only four and five amino acids, worked as effective supramolecular hydrogelators for buffer solutions at low gelator concentrations (0.5-1.5 wt %). Among 10 different oligopeptides synthesized, peptide P1 (Ac-Phe-Phe-Phe-Gly-Lys) showed high gelation ability. Transmission electron microscopy observations suggested that the peptide molecules self-assembled into nanofibrous networks, which turned into gels. The hydrogel of peptide P1 showed reversible thermal gel-sol transition and viscoelastic properties typical of a gel. Circular dichroism spectra revealed that peptide P1 formed a β-sheetlike structure, which decreased with increasing temperature. The self-assembly of peptide P1 occurred even in the presence of nutrients in culture media and common surfactants. Escherichia coli and yeast successfully grew on the hydrogel. The hydrogel exhibited low cytotoxicity to animal cells. Finally, we demonstrated that functional compounds can be released from the hydrogel in different manners based on the interaction between the compounds and the hydrogel.

Tuning charge carrier transport and optical birefringence in liquid-crystalline thin films: A new design space for organic light-emitting diodes

Liquid-crystalline organic semiconductors exhibit unique properties that make them highly interesting for organic optoelectronic applications. Their optical and electrical anisotropies and the possibility to control the alignment of the liquid-crystalline semiconductor allow not only to optimize charge carrier transport, but to tune the optical property of organic thin-film devices as well. In this study, the molecular orientation in a liquid-crystalline semiconductor film is tuned by a novel blading process as well as by different annealing protocols. The altered alignment is verified by cross-polarized optical microscopy and spectroscopic ellipsometry. It is shown that a change in alignment of the liquid-crystalline semiconductor improves charge transport in single charge carrier devices profoundly. Comparing the current-voltage characteristics of single charge carrier devices with simulations shows an excellent agreement and from this an in-depth understanding of single charge carrier transport in two-terminal devices is obtained. Finally, p-i-n type organic light-emitting diodes (OLEDs) compatible with vacuum processing techniques used in state-of-the-art OLEDs are demonstrated employing liquid-crystalline host matrix in the emission layer.

Diarylethene-based xerogels: the fabrication of more entangled networks driven by isomerization and acidofluorochromism

The organogels were formed from fully-conjugated styrylbenzoxazoles and styrylbenzothiazoles without traditional gelation groups.

Ultrasound- and Temperature-Induced Gelation of Gluconosemicarbazide Gelator in DMSO and Water Mixtures

We have developed amphiphilic supramolecular gelators carrying glucose moiety that could gel a mixture of dimethyl sulfoxide (DMSO) and water upon heating as well as ultrasound treatment. When the suspension of gluconosemicarbazide was subjected to ultrasound treatment, gelation took place at much lower concentrations compared to thermal treatment, and the gels transformed into a solution state at higher temperatures compared to temperature-induced gels. The morphology was found to be influenced by the nature of the stimulus and presence of salts such as KCl, NaCl, CaCl₂ and surfactant (sodium dodecyl sulphate) at a concentration of 0.05 M. The gel exhibited impressive tolerance to these additives, revealing the stability and strength of the gels. Fourier transform infrared spectroscopy (FTIR) revealed the presence of the intermolecular hydrogen bonding interactions while differential scanning calorimetry (DSC) and rheological studies supported better mechanical strength of ultrasound-induced (UI) gels over thermally-induced (TI) gels.