Organic functional materials based buffer layers for efficient perovskite solar cells

In this review, we highlight the recent development of organic π-functional materials as buffer layers in constructing efficient perovskite solar cells(PVSCs). By following a brief introduction on the PVSC development, device architecture and material design features, we exemplified the exciting progresses made in field by exploiting organic π-functional materials based hole and electron transport layers(HTLs and ETLs) to enable high-performance PVSCs.     

Organometallic functional materials based on siloxane block copolymers

Efficient synthetic approaches to designing nanoscale hybrid organo-inorganic composites containing metal (Zn, Cd, Cu, Zr) sulfides or oxides have been developed. These approaches were used to design the materials with specific electrophysical properties and controllable phase structure. The composites can be used as electroinsulating functional materials (adhesives, varnishes, coatings, and sealants) in microelectronics.     

Nanoscopic optical sensors based on functional supramolecular hybrid materials

This review highlights how the combination of supramolecular principles and nanoscopic solid structures enables the design of new hybrid sensing ensembles with improved sensitivity and/or selectivity and for the targeting of analytes for which selectivity is hard to achieve by conventional methods. Such ideas are bridging the gap between molecules, materials sciences and nanotechnology. Relevant examples will be detailed, taking into account functional aspects such as (1) enhanced coordination of functionalized solids, (2) enhanced signalling through preorganization, (3) signalling by assembly–disassembly of nanoscopic objects, (4) biomimetic probes utilizing discrimination by polarity and size and (5) distinct switching and gating protocols. These strategies are opening new prospects for sensor research and signalling paradigms at the frontier between nanotechnology, smart materials and supramolecular chemistry.     

非共价键自组装有机功能材料

分子自组装对于某些化学反应过程、生物化学过程及生命活动的模拟等方面具有重要的意义。本文对非共价键组装方式自组装的有机功能材料的分类，结构、性质、自组装机理以及研究进展进行了综述。     

Nearly 100% exciton utilization in highly efficient red OLEDs based on dibenzothioxanthone acceptor

Improving the utilization of excitons has always been an important topic for the development of electroluminescence devices. In this work, we designed and synthesized three red TADF emitters TPA-DBT12, TPA-DBT3 and DTPA-DBT by employing dibenzothioxanthone (DBT) acceptor framework to stabilize the locally excited triplet state to participate in the reverse intersystem crossing (RISC) process. The fast RISC process and singlet radiation decay process gave rise to evidently enhanced exciton utilization. All of the red OLEDs based on these materials showed maximum EQE over 11% and high exciton utilization close to 100%. This work not only extend the acceptor framework for red materials but also provide a new perspective for the design of highly efficient red TADF materials with 100% exciton utilization by managing locally excited triplet state.     

Fire intumescent compositions based on the intercalated graphite

A possibility of creation of the swelling type fire-retardant compositions of paints and varnishes based on intercalated graphite dispersed in the polymer matrix in the amount of 5.0–15.0 mass percent was investigated and proved. The expediency of use of the rough aqueous dispersions of polymers obtained with the use of protective colloids as a binder was shown.     

三聚茚有机光电功能材料在太阳电池领域的应用

三聚茚可经一步反应合成,功能化程度高,是规整的、纳米级的刚性结构,能通过平衡分子之间聚集尺寸的大小来控制激子扩散长度继而调节分子之间的相互作用;而且,三聚茚具有优良的荧光性能、热稳定性能和空穴传输性能,是应用广泛的有机光电材料.本文从太阳电池领域(有机太阳电池、钙钛矿太阳电池和染料敏化太阳电池)出发,综述了国内外对三聚茚材料的研究工作,总结了三聚茚材料对太阳电池领域的发展所做出的贡献.     

稀土/L型沸石主-客体发光功能材料的研究进展

沸石微孔晶体材料作为客体功能物种的主体材料在主-客体组装化学中发挥着越来越重要的作用,在微型激光器、非线性光学、生物成像、光放大及光显示等高技术领域已显示出广阔、诱人的发展前景.本文介绍国内外,特别是河北工业大学在稀土/L型沸石主-客体杂化功能材料的组装、结构及其发光性能的研究工作,具体包括：稀土有机配合物在L沸石孔道内的组装、L型沸石-有机高分子透明杂化发光材料的制备及稀土有机配合物诱导控制的L型沸石自组装等.此外,本文对稀土/L型沸石主-客体杂化发光功能材料的研究进行了展望.     

Layered compounds based on perforated graphene

A method to obtain previously unknown layered structure composed of stacks of perforated graphene sheets is developed. The method consists in the thermal decomposition of graphite oxide in the concentrated H₂SO₄ and H₃PO₄ medium. In order to confirm the presence of holes in graphene layers, a large set of chemical and physicochemical analysis methods are applied. Based on a new matrix, treated thermally and chemically, layered compounds are obtained: oxide, fluoride, and fluoroxide of two types. The obtained compounds are analyzed by transmission electron microscopy, infrared absorption spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and powder X-ray diffraction.     

Biopolymer-layered polysilicate micro/nanocomposite based on chitosan intercalated in magadiite

On the basis of their high adsorption and cation exchange capacity, swelling potential and low toxicity, layered sodium silicate magadiite (Na–magadiite) is an attractive solid for intercalation of polymers. This study envisages the intercalation of cationic biopolymer chitosan (Chit) in Na–magadiite to prepare a Chit/magadiite micro/nanocomposite. Characterisation of starting-magadiite, pure chitosan and Chit/magadiite were investigated using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy and thermal analysis. XRD confirmed that the chitosan had been intercalated into the interlayer space of magadiite by increasing the basal spacing, d₀₀₁ from 15.6 Å to 21.45 Å. The presence of characteristic bands of biopolymer and layered silicate in Chit/magadiite were confirmed by FTIR analysis. The thermal stability of micro/nanocomposite was evaluated by thermogravimetry analysis. The results suggested the formation of electrostatic interactions by protonated amine groups with the negatively charged magadiite surface as well as intercalation in the form of a predominant monolayer arrangement of chitosan chains in layered silicate magadiite.     

Thermal stability of hybrid materials based on epoxy functional (poly)siloxanes

Epoxy functional (poly)siloxanes are one of the most important classes of modified silicones. Due to high reactivity of epoxy group and specific features of siloxane chain, they can make an excellent raw material for synthesis of hybrid materials. Results obtained in this study have shown that both the modification of epoxy resins with epoxy functional disiloxanes as well as the application of polysiloxanes with long polysiloxane chains and a specified content of epoxy groups makes it possible to produce hybrid materials of very good thermal stability. Crosslinking reactions were carried out with use of four diamines of which the best one appeared to be 4,4??-diaminodiphenylmethane. The highest thermal stability was found in the case of hybrid materials obtained from epoxy functional polysiloxanes.     

基于高激子利用率的第三代有机电致发光材料的研究进展

荧光OLED材料由于受到激子统计规律的限制,其能量利用效率小于25%.为了开发高效而价廉的OLED材料,突破激子统计规律的研究受到了广泛关注,目前的研究主要集中在三个方向:突破激子统计限制的共轭聚合物材料、三线态反系间窜越(RISC)的延迟荧光材料以及"热激子"(hot exciton)与杂化局域-电荷转移(HLCT)激发态材料.对近年来在基于高激子利用率的第三代有机电致发光材料的研究方面的进展情况进行综述,同时对其未来的研究前景进行了展望.     

Catalytic amplification based on hole-transporting materials as efficient metal-free electrocatalysts for non-enzymatic glucose sensing

Hole-transporting materials with tunable structures and properties are mainly applied in organic light-emitting diodes as transport layer. But their catalytic properties as signal amplifiers in biological assays are seldom reported. In this paper, a starburst molecule, 4,4,4″-tri(N-carbazolyl)-triphenylamine (TCT), containing a triphenylamine as the central core and three carbazoles as the peripheral functional groups was designed and synthesized. Subsequently, the hole-transporting material based on the TCT polymer, poly(TCT) (PTCT), was achieved via a low-cost electrochemical method and exploited as an efficient metal-free electrocatalyst for non-enzymatic glucose detection. Here, this hole-transporting material served three purposes: electrochemical recognition (owing to hydrogen bonding interaction and the biomimetic microenvironment created by the polymer), electrocatalysis (owing to the hole-transporting capability of triphenylamine and the catalytic property of carbazole), and signal amplification (owing to energy migration along the conductive polymer backbone). The electrocatalytic and sensing performances of the sensor based on PTCT were evaluated in detail. Results revealed that the PTCT film could efficiently catalyze the oxidation of glucose at a less-positive potential (+0.20 V) in the absence of any enzymes. The response to glucose was linear in the concentration range of 1.0–6000 μM, and the detection limit was 0.20 μM. With good stability and selectivity, the proposed sensor could be feasibly applied to detect glucose in practical samples. The encouraging sensing performances suggest that the hole-transporting material is one of the promising biomimetic catalysts for electrocatalysis and relevant fields.     

Thiuram disulfide intercalated hybrid materials of layered lead and cadmium iodides

Thiuram disulfide intercalates of lead(II) and cadmium(II) were prepared by the reaction of binary layered metal iodides with five dithiocarbamates in air. The intercalates were characterized by elemental analysis, Powder X-ray diffraction (XRD), infrared (IR), ultraviolet–visible spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM) techniques. IR showed increased contribution of the thioureide bond and the presence of weak disulfide stretching frequency. Powder XRD showed the characteristic intermediate 2θ signal confirming the intercalation. Powder XRD clearly differentiated intercalates from the iodinated product of dithiocarbamate. As the bulkiness of substituents on disulfide increased, “d” also increased. The higher thermal stability associated with intercalates clearly suggests a strong ionic interaction and a difficult de-intercalation. SEM images of lead intercalates indicated crystalline nature. The intercalates appeared as rods or spheres. The diallyl-intercalate, [PbI₂](H₅C₃)₂NCSS-SSCN(C₃H₅)₂ (where (H₅C₃)₂NCSS-SSCN(C₃H₅)₂ is diallylthiuram disulfide), shows “net like structures.” Intercalation of oxidized dithiocarbamates in the “galleries” of layered PbI₂/CdI₂ is observed. HRTEM and AFM analysis of intercalates showed the particles to be nano-rods.     

Layered double hydroxides intercalated with borate anions: Fire and thermal properties in ethylene vinyl acetate copolymer

Fire and thermal properties of ethylene vinyl acetate (EVA) composites prepared by melt blending with layered double hydroxides (LDH) have been studied. Two types of LDHs intercalated with borate anion were prepared using the coprecipitation method and the metals Mg²⁺, Zn²⁺ and Al³⁺. Characterization of the LDHs and the EVA composites was performed using X-ray diffraction, thermogravimetric analysis, and cone calorimetry. Thermal analyses show that the addition of LDHs improves the thermal stability of EVA. Fire properties evaluated using the cone calorimeter were significantly improved in the EVA/LDH composites. The peak heat release rate was reduced by about 40% when only 3% by weight of the LDH was added to the copolymer. Comparison of the fire properties of the LDHs with those of aluminum trihydrate (ATH), magnesium hydroxides (MDH), zinc hydroxide (ZH) and their combinations at 40% loading, reveal that the LDHs were more effective than when MDH and ZH are used alone.     

Electrochemical characterization of composite membranes based on crown-ethers intercalated into montmorillonite

Oxyethylene macrocyclic compounds (crown-ethers) act as ligands of intracrystalline cations of certain layered silicates as montmorillonites. Stable intercalation materials are formed which are used to prepare organic-inorganic membranes by encapsulating these intercalation compounds with a poly-butadiene thin coating. Electrochemical Impedance Spectroscopy (EIS) is used to study the resulting composite membranes in contact with aqueous electrolytes. From the impedance plots, the ionic resistance of the membranes is obtained. The thickness of the polybutadiene coating is an important factor determining the ability of ions to pass across the membrane. Marked differences in the ionic resistance are observed as a function of the nature of the interlayer macrocyclic compound. For non-intercalated montmorillonite membranes, the ionic resistance is strongly reduced, whereas for some crown-ether intercalated materials such as 18-crown-6 and dibenzo 24-crown-8, iono-selective membranes are obtained. Concerning the nature of the electrolyte, cations exhibiting greater hydration energies show higher difficulties to pass through the membrane and, consequently, the ionic resistance increases.     

Electron-transfer in molecular functional materials

We discuss electron-transfer processes that govern the physics of several materials or systems of interest for advanced applications. The discussion touches upon several topics, ranging from solvatochromism to solvent-induced symmetry breaking, from excitonic to cooperative effects in molecular crystals, from phase transitions to vibrational contributions to the dielectric constant in organic materials, from spectroscopy to molecular transport. In all these diverse systems electron transfer (ET) plays a major role and is discussed with reference to simple models for delocalized charges.