Organic-inorganic polymer hybrids based on unsaturated polyester

Organic-inorganic polymer hybrid materials were first prepared using an unsaturated polyester (UPE) as an organic component. Homogeneous UPE/silica gel hybrids formed via π-π interactions between benzene rings of the two constituents. Photocrosslinking of UPE in the hybrids resulted in the formation of interpenetrating polymer network structure.     

Design and synthesis of small molecules with difluoroquinoxaline units for OSCs

Abstract

We designed and synthesized three novel small molecule donors (SM1, SM2 and SM3) that consist of thiophene as the electron-donating end group and 6,?7-?difluoroquinoxaline moiety as a novel electron-withdrawing core group. The organic low band gap molecules with 6,?7-?difluoroquinoxaline and thiophene units were synthesized using Stille coupling to generate SM1, SM2 and SM3. The absorption of SM2 and SM3 in solution was red shifted due to increased conjugation length of added thiophene units. In case of SM2 and SM3, introduction of hexyl chain in terminal thiophene units improve solubility in organic solvent. The maximum absorption peaks of SM1, SM2 and SM3 in solid thin films were at 482, 505 and 518?nm, respectively. SM3 was red shifted as compare to SM2 due to increased π-π stacking of electron donor materials.     

Hybrid glass-like films through sol–gel techniques

Since the time sol–gel was suggested as a nonmelting technique for the preparation of glasses, an enormous amount of work has been done, moving from the more traditional glasses to new materials. Among these, hybrid organic–inorganic materials are of particular interest, not only for the amount of the applications they may be used for, but also because of their structural characteristics: hybrids are a mix, at molecular level, of inorganic and organic moieties, where the organic ones may be simply dissolved in the matrix or behave as network former or modifier. The most recent results on the synthesis of this type of films, obtained by the author and co-workers, will be presented and discussed. In particular, the focus will be on the possibility to control the structural development by acting on the organic and inorganic polymerization separately and the challenges that this approach offers.     

Characteristics of colored inorganic–organic hybrid materials

Inorganic–organic hybrid glasses are relatively new nanometric materials of Ormosil’s group (organic modified silicates). There co-existence, on a molecular scale, exists between inorganic structures in the form of silica-oxide network and organic structures based on carbon links. Properties of these materials are intermediate between those of inorganic glasses (hardness, chemical and thermal resistance) and organic polymers (low temperature of obtaining, elasticity of structure). The hybrid materials are compatible matrices for organic compounds such as organic dyes, laser dyes, photo-chromic compounds, etc. Inorganic–organic hybrid glasses are usually produced in the form of thin coatings on various bases using a low-temperature sol-gel process. These coatings, depending on the kind and amount of units, building their structure, show various properties: refractive index changing in a wide range, anti-static properties, anti-reflection, corrosion protection, intensive color, luminescence and others. That is why these materials found application as protective and colored covering of glass articles as well as in new technical areas. The aim of this paper is obtaining and characterizing colored inorganic–organic coatings on glass, considering both protective and colored properties. These materials have been produced from phenyltriethoxysilane (PhTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), aluminium tri-sec-butylate (TBA); (PGT matrix). The structure of PGT matrix was determined using the FTIR, ²⁹Si MAS NMR and ²⁷Al MAS NMR examinations. It has been found that chemical bonds occur between structural units. The two groups of organic dyes were used for coloring the coatings. The first group consisted of ORASOL dyes, chiefly based on various metal complexes. These dyes have a wide range of commercial utilization. The second group included the organic, intensive dyes obtained in the laboratory and are inaccessible for sale. The coloring coatings were coated on flat glass using the dip-coating method. The samples were submitted for thermal treatment at temperatures of 100 and 200 °C. Investigation of chemical resistance (boiling in water for 1 h) was made for coated materials after thermal treatment at 100 °C. UV–VIS transmission of colored coatings was examined after each stage of thermal treatment and also after hydrolytic resistance examination. The quality of the coatings and their thickness were estimated by SEM observations. The obtained, inorganic–organic coatings were characterized by good chemical resistance and stability of color.     

Molecular Design of Carbazole-based Dyes and the Influence of Alkyl Substituent on the Performance of Dye-Sensitized Solar Cells

Carbazole is an alternant polycyclic aromatic hydrocarbon consisting of three fused rings with a large, aromatic system, containing nitrogen atom showing extensive electron delocalization. In this work, carbazole applied as π-conjugated bridge to construct electron donor–π–electron acceptor (D–π–A) organic dyes, where barbutiric acid and thiazolidine-2,4-dione as electron acceptor. The effects of these three acceptors and length of alkyl on the performance of the DSSCs were investigated systematically along with their photophysical and photo electrochemical properties. These series of organic dyes include (B-CH, B-C B, DT-CB, DB-CB). Our investigation indicate among dyes containing butyl as same donor, DT-CB exhibited the maximum overall conversion efficiency of 1.44% and from dyes by deferent electron donor B-CH shows conversion efficiency of 1.47%.     

Electrical and dielectric behavior of the system Gd1‐xBaxCoO3 (x = 0.00, 0.10, 0.20) synthesized by chemical route

The samples in the system Gd_1‐xBa_xCoO₃ (x = 0.00, 0.10, 0.20) were prepared by chemical route. These samples form single‐phase materials, which were confirmed by XRD and TGA studies. The presence of interfacial polarization is responsible for high value of dielectric constant in these materials. The conductivity observed in Gd_1‐xBa_xCoO₃ system may be due to mobile holes created by excitation of an electron from the π* band to an acceptor level.     

Synthesis and Properties of a New Kind of One-Dimensional Conductors 17. Studies on monomeric and polymeric phthalocyaninato-iron(II) and -cobalt(II) complexes

A new approach for a one-dimensional organic conductor with a chemically bonded backbone is presented. The proposed compounds consist of a linear arrangement of transition metal atoms, e.g. Fe, Co, bridged by linear bidentate π-electron containing ligands, e.g. pyrazine, 4,4'-bipyridine, and 1,4-diisocyanobenzene. This structure is stabilized by the tetradentate planar phthalocyanine molecule complexing each octahedrally coordinated central atom in its equatorial plane. The synthesis and characterization of the monomeric, dimeric and polymeric compounds PcML/PcML₂, PcM-L-PcM and [PcML]_n are described and a comparison of their electrical conductivity as a function of their structural features is given in detail. The electrical conduction of the monomeric units increases after polymerisation by a factor of 10⁷ without doping. In the second part soluble tetrasubstituted phthalocyaninato(IVB)-metalloxanes are described and the effect of homogeneous and heterogeneous iodination on conductivity is discussed.     

Investigation of charge carriers transport from extraction current transients of injected charge carriers

The extraction of injected charge carriers technique for investigation of the transport in the metal-insulator-semiconductor structures is proposed. The mobility and the amount of accumulated charge carriers are determined from extraction current transients in both, small charge and space charge limited current cases. The extraction currents transients obtained experimentally in the structures with various organic materials are demonstrated.     

Playing with nanosegregation in discotic crown ethers: from molecular design to OFETs,nanofibers and luminescent materials

Discotic liquid crystals are promising materials for electronic device applications. Combining extended π-systems with crown ethers may further open access to functional supramolecular hybrid materials. In the present publication, we briefly summarise recent literature developments and focus in a second part on our work in the field of discotic crown ethers. The crown ether derivatives are conveniently accessible by convergent syntheses which allow a high degree of variation with respect to side chains, mesogenic unit, size and symmetry of the crown core, metal complexation and counterion. This set of compounds provides a basis for systematic structure–property relationship investigations. Numerous experimental studies identified factors being crucial for mesophase stabilisation and geometry and furthermore led to novel room-temperature crown ether mesogens. The latter were obtained by congestion of the mesogenic units and even introduction of peripheral δ-methyl branched side chains. The formation of molybdenum clustomesogens and their application as luminescent hybrid materials is also described.     

Sol-gel-derived organic-inorganic hybrid materials

Optically transparent organic-inorganic hybrid coating materials have been prepared by a sol-gel process. Four different types of the coating material produced by TWI in Cambridge, UK using the patented Vitresyn^® method, all identical in terms of the starting materials, but differing in terms of their relative proportions, have been examined. Tetraethoxysilane was used as the primary inorganic precursor and urethane acrylate was used as the source of the organic component. 3-(Trimethoxysilyl)propyl methacrylate was used as both a secondary inorganic source and a silane coupling agent to improve the compatibility of the organic and inorganic phases. The degree of chemical interaction of the organic and inorganic phases after processing was determined by ²⁹Si and ¹³C nuclear magnetic resonance and Fourier transform infrared spectroscopy. The effect of the relative amount of inorganic starting component in these hybrid materials on their thermal properties was investigated through differential scanning calorimetry and thermogravimetric analysis. Similar degrees of chemical interaction between the organic and inorganic phases were found in all four samples. T³, Q³ and Q⁴ are the main cross-linking network structures in these hybrid systems, the relative proportions of which are determined by the relative proportions of the starting materials.     

Syntheses and Photovoltaic Properties of Octyl Cyanoacetate Terminated Small Molecules Based on Benzo[1,2-b:4,5-b’]dithiophene for OPVs

There have been tremendous efforts to synthesize photoactive materials that are consisted of both donor and acceptor components together to increase the power conversion efficiency (PCE) of organic photovoltaic cells (OPVs). In order to improve the performance of the OPVs, in this study, we proposed new A-D-A (Acceptor-Donor-Acceptor) type small molecular donors based on the donor unit of benzo[1,2-b:4.5-b’]dithiophene (BDT) with an acceptor unit of alkyl cyanoacetate. We characterized prepared photoactive materials using ¹H NMR spectroscopy, DSC, CV (cyclic voltammetry), and UV/Vis spectroscopy. We also investigated the relationship between PCEs of OPVs and the active materials with variation of substituted methyl groups. The OPVs based on synthesized photoactive materials with different methyl substitutions showed different PCEs. Our results indicate that synthesized small molecular donor materials are promising donor materials for performance OPVs     

Recent advances with electro-optic polymers

Abstract

In recent years the electro-optic polymers emerged as an important branch of material science. This growth and interest is fundamentally motivated by practical application of these materials in second-order nonlinear optics and in waveguiding configuration. Indeed, these materials marry excellent optical quality of amorphous σ bonded polymers with enhanced first hyperpolarizability of imbedded organic nonlinear optical molecules. Although a big progress was achieved with them, concerning particularly the science, understanding and applications, some problems remain still incompletely solved, particularly the stability of induced polar order by the application of external electric field and the molecule aggregation. In this review paper we recall techniques of thin film fabrication, poling, characterization of NLO properties and discuss more precisely problems of molecule aggregation as well as the temporal decay of polar order. A novel 3D second-order NLO chromophores, namely the [2] paracyclophanes, which may help to limit the aggregation, are proposed. We show, in particular, that this molecule can be poled in doped PMMA thin films. Practical applications of electro-optic polymers are also reviewed and discussed.     

“微距升华”晶体生长方法

随着功能器件向微型化发展,微纳米尺度的低维晶体成为构建新一代功能器件的材料基础。传统的体块单晶生长方法不适用于低维晶体。长久以来,对新型低维材料的研究依赖于机械剥离、溶液法和化学/物理气相沉积等方法,这些方法在效率、可控性和适用性等方面存在诸多限制,因此发展高效可控的低维晶体新型生长方法成为实现这些低维材料器件实用化的前提。山东大学晶体材料国家重点实验室陶绪堂、刘阳团队基于多年来在分子材料结晶基础方面的研究成果,发明了新的“微距升华”低维晶体生长方法。“微距升华”法利用原料与生长衬底之间的微小间距,可以在常压下实现常规物理气相传输中需要高真空才能够达到的分子流传输模式,使生长过程不再受传质限制,因此微距升华法无须真空和载气,速度快,原料利用率接近100%。该方法适用于大部分的有机半导体、金属配合物,甚至含有大量羧基、羟基的药物分子及熔点在一定范围内的无机物晶体,生长的微纳米晶体与电子器件制程匹配,屡次创新器件迁移率记录。新方法受到业界广泛关注,已被多国科学家采用。     

Recent progress on triphenylamine materials: synthesis,properties, and applications

Triphenylamine is a propeller-like structural chromophore with a nitrogen atom center. The compound has a large steric hindrance and hyper conjugation electronic effect, which can enhance the stability of the nitrogen atomic radical. Triphenylamine materials also have a high hole mobility due to their unique free radicals nature. In this review, we started with the methods of the synthesis including traditional Ullmann, Suzuki Coupling, Heck, Wittig, Stille, and Sonogashira Reaction synthesis, and also the basic experimental and theoretical methods for the characterization of triphenylamine materials. Then, we discussed the properties of triphenylamine, including the optoelectronics, electroluminescence, and electrochromism. Finally, we reviewed the recent progress in the main applications of triphenylamine materials in the field of organic optoelectronic solar cells, electroluminescence materials, and electrochromic materials. In conclusion, this review of triphenylamine materials is a valuable resource for both theorists and experimentalists who are focus on these exciting compound materials.     

Nucleation

Crystallization starts with nucleation and control of nucleation is crucial for the control of the number, size, perfection, polymorphism and other characteristics of crystalline materials. This is particularly true for crystallization in solution, which is an essential part of processes in the chemical and pharmaceutical industries and a major step in physiological and pathological phenomena. There have been significant recent advances in the understanding of the mechanism of nucleation of crystals in solution. The foremost of these are the two-step mechanism of nucleation and the notion of the solution-crystal spinodal. According to the two-step mechanism, the crystalline nucleus appears inside pre-existing metastable clusters of size several hundred nanometers, which consist of dense liquid and are suspended in the solution. While initially proposed for protein crystals, the applicability of this mechanism has been demonstrated for small molecule organic materials, colloids, polymers, and biominerals. This mechanism helps to explain several long-standing puzzles of crystal nucleation in solution: nucleation rates which are many orders of magnitude lower than theoretical predictions, the significance of the dense protein liquid, and others. At high supersaturations typical of most crystallizing systems, the generation of crystal embryos occurs in the spinodal regime, where the nucleation barrier is negligible. The solution-crystal spinodal helps to understand the role of heterogeneous substrates in nucleation and the selection of crystalline polymorphs. Importantly, these ideas provide powerful tools for control of the nucleation process by varying the solution thermodynamic parameters.     

生物质炭的制备、功能改性及去除废水中有机污染物研究进展

生物质炭具有原材料来源广泛、比表面积大、孔隙结构丰富、表面官能团易调控等优势,在有机污染废水处理领域展现良好的应用前景。然而,生物质炭的不同原材料、制备方法、改性措施等在很大程度上影响着生物质炭的物化性质,从而对有机污染废水表现出不同的性能和作用机制。本文主要基于生物质炭结构特性,针对其制备方法、改性手段和措施展开叙述,并总结了生物质炭用于有机污染废水处理的现状和未来发展机遇。     

非金属掺杂改性g-C3N4光催化降解水中有机污染物的研究进展

近年来,石墨相氮化碳(g-C₃N₄)以其合适的带隙宽度、丰富的活性位点和成本低廉等优点,成为新兴的可见光响应非金属光催化剂,被广泛应用于光催化降解有机污染物领域。然而,纯g-C₃N₄对可见光的吸收效率较低且光生电子和空穴复合速率快,导致其光催化活性处于较低水平。基于g-C₃N₄的非金属特性,通过非金属掺杂可以有效提高g-C₃N₄的光催化性能,引起了学者们的广泛关注。本文介绍了目前非金属掺杂g-C₃N₄复合材料常见的制备方法,着重归纳了不同类型的非金属掺杂g-C₃N₄光催化降解水中有机污染物的相关研究进展,探讨其作为光催化剂在可见光条件下降解有机污染物的相关机理。最后,提出目前g-C₃N₄基复合材料在光催化降解水中有机污染物中所面临的挑战,旨在为非金属掺杂g-C₃...     

Crystal structure of the new organic conductor (TSeF)7[FeNO(CN)5]2 with unusual molecular packing of conducting layer

X-ray single crystal diffraction study of the new molecular conductor (TSeF)₇[FeNO(CN)₅]₂ has been carried out at room temperature and 130 K. The crystal structure is composed by layers of π-electron donors TSeF, separated by anion layers along the a-direction. The conducting organic layer has unusual for molecular conductors arrangement of neutral monomeric and charged hexameric TSeF units orthogonally packed with respect to each other. Another specific feature of the structure is fully ordered state of the nitroprusside anion and deep penetrating of its functional NO-group into the adjacent organic layer.     

Synthesis and characterization of SiO2-PEG hybrid materials

Sol-gel is a promising technique for the synthesis of organic-inorganic hybrid materials both of class I and II. In materials of class I organic molecules are physically entrapped in an inorganic matrix, while in those of class II organic and inorganic parts are connected by covalent bonds. In this paper a sol-gel procedure to obtain SiO₂-PEG hybrids of class I, in which PEG is simply mixed at the sol stage, is compared to a sol-gel procedure to obtain SiO₂-PEG hybrid materials of class II, where a particular sol-gel Si-C precursor is synthesized. XPS analyses showed the different distribution of the organic phase in the SiO₂ matrix and the bond between PEG and SiO₂ for hybrids of class II. The PEG molecule in hybrid of class II showed an enhanced thermal stability up to 350 °C. Doping with a lithium salt was performed on hybrids of class II, and the ionic conductivity was measured.     

Manifestation of optical activity in different materials

Various manifestations of optical activity (OA) in crystals and organic materials are considered. Examples of optically active enantiomorphic and nonenantiomorphic crystals of 18 symmetry classes are presented. The OA of enantiomorphic organic materials as components of living nature (amino acids, sugars, and proteins) is analyzed. Questions related to the origin of life on earth are considered. Examples of differences in the enantiomers of drugs are shown. The consequences of replacing conventional left-handed amino acids with additionally right-handed amino acids for living organisms are indicated.