Organic-inorganic Hybrid Structures Research Articles

Strong Coupling between Surface Plasmon Polaritons and Molecular Vibrations.

We report on the strong coupling of surface plasmon polaritons and molecular vibrations in an organic-inorganic plasmonic hybrid structure consisting of a ketone-based polymer deposited on top of a silver layer. Attenuated-total-reflection spectra of the hybrid reveal an anticrossing in the dispersion relation in the vicinity of the carbonyl stretch vibration of the polymer with an energy splitting of the upper and lower polariton branch up to 15meV. The splitting is found to depend on the molecular layer thickness and saturates for micrometer-thick films. This new hybrid state holds a strong potential for application in chemistry and optoelectronics.

Fabrication and characterization of materials and structures for hybrid organic–inorganic photonics

Hybrid organic–inorganic integrated photonics integrate the organic material, as a part of active layer, with inorganic structure, and it is the organic component that extends the functionalities as compared to inorganic photonics. This paper presents the results of fabrication and characterization of inorganic and organic layers, as well as of hybrid organic–inorganic structures. Inorganic oxide and nitride materials and structures were grown using plasma enhanced chemical vapor deposition. As a substrate for tested organic layers and for preparation of multilayer structures, commercially available SiO2 created by thermal oxidation on Si was used. The hybrid organic–inorganic structures were prepared by spin coating of organic materials on SiO2/Si inorganic structures. As the basic photonics devices, the testing strip inorganic and organic waveguides were fabricated using reactive ion etching. The shape of fabricated testing waveguides was trapezoidal and etched structures were able to guide the radiation. The presented technology enabled to prepare hybrid organic–inorganic structures of comparable dimensions and shape. The fabricated waveguides dimensions and shape will be used for optimisation and design of new lithographic mask to prepare photonic components with required characteristics.

Piezoelectric scattering limited mobility of hybrid organic-inorganic perovskites CH3NH3PbI3

Carrier mobility is one of the most important parameters for semiconducting materials and their use in optoelectronic devices. Here we report a systematic first principles analysis of the acoustic phonon scattering mechanism that limits the mobility of CH3NH3PbI3 (MAPbI3) perovskites. Due to the unique hybrid organic-inorganic structure, the mechanical, electronic and transport properties are dominated by the same factor, i.e. the weak interatomic bond and the easy rotation of methylammonium (MA) molecules under strain. Both factors make MAPbI3 soft. Rotation of MA molecule induces a transverse shift between Pb and I atoms, resulting in a very low deformation potential and a strong piezoelectricity in MAPbI3. Hence the carrier mobility of pristine MAPbI3 is limited by the piezoelectric scattering, which is consistent to the form of its temperature dependence. Our calculations suggest that in the pristine limit, a high mobility of about several thousand cm2 V−1 S−1 is expected for MAPbI3.

Machine learnt bond order potential to model metal-organic (Co-C) heterostructures.

A fundamental understanding of the inter-relationships between structure, morphology, atomic scale dynamics, chemistry, and physical properties of mixed metallic-covalent systems is essential to design novel functional materials for applications in flexible nano-electronics, energy storage and catalysis. To achieve such knowledge, it is imperative to develop robust and computationally efficient atomistic models that describe atomic interactions accurately within a single framework. Here, we present a unified Tersoff-Brenner type bond order potential (BOP) for a Co-C system, trained against lattice parameters, cohesive energies, equation of state, and elastic constants of different crystalline phases of cobalt as well as orthorhombic Co2C derived from density functional theory (DFT) calculations. The independent BOP parameters are determined using a combination of supervised machine learning (genetic algorithms) and local minimization via the simplex method. Our newly developed BOP accurately describes the structural, thermodynamic, mechanical, and surface properties of both the elemental components as well as the carbide phases, in excellent accordance with DFT calculations and experiments. Using our machine-learnt BOP potential, we performed large-scale molecular dynamics simulations to investigate the effect of metal/carbon concentration on the structure and mechanical properties of porous architectures obtained via self-assembly of cobalt nanoparticles and fullerene molecules. Such porous structures have implications in flexible electronics, where materials with high electrical conductivity and low elastic stiffness are desired. Using unsupervised machine learning (clustering), we identify the pore structure, pore-distribution, and metallic conduction pathways in self-assembled structures at different C/Co ratios. We find that as the C/Co ratio increases, the connectivity between the Co nanoparticles becomes limited, likely resulting in low electrical conductivity; on the other hand, such C-rich hybrid structures are highly flexible (i.e., low stiffness). The BOP model developed in this work is a valuable tool to investigate atomic scale processes, structure-property relationships, and temperature/pressure response of Co-C systems, as well as design organic-inorganic hybrid structures with a desired set of properties.

2,6‐Diisopropylanilinium Bromobismuthates

A systematic approach to obtain bromobismuthates with various bismuth/halide ratios stabilised by 2,6‐diisopropylanilinium cations [ArNH3] (Ar = 2,6‐diisopropylphenyl) is presented. New bromobismuthate compounds [(ArNH3)(BiBr4)]∞ (1), [(ArNH3)3(Bi2Br9)]∞ (2), [(ArNH3)3(BiBr6)] (3) and [(ArNH3)4(BiBr6)(Br)] (4) with Bi/Br ratios of 1:4, 1:4.5, 1:6 and 1:7 have been isolated and structurally characterised. [Bi2Br9]∞ is a new structural motif in halobismuthate chemistry. In all the compounds, extensive hydrogen bonding is observed between the bromobismuthate moiety and the 2,6‐diiosopropylanilinium cation, thus stabilising the inorganic–organic hybrid structures. Preliminary optical spectroscopic studies indicate that the optical band gap can be tuned by controlling the bismuth/halide ratio, which results in different dimensionalities in the halobismuthate structure. The compounds exhibit thermal stability up to 250 °C.

Electrospun Photochromic Hybrid Membranes for Flexible Rewritable Media.

Ink-free rewritable media has attracted great attention as a potential alternative to current paper prints, owing to its benefits to reducing paper production and consumption for environmental protection. It is desirable to develop rewritable media based on cheap, robust, and fast-response photochromic systems. Herein, we report the design and fabrication of flexible and photorewritable PVP/a-WO3 hybrid membranes through electrospinning, on which images with high resolution can be photoprinted and heat-erased for over 40 cycles. The well conjugated organic-inorganic hybrid structure endows a fast "electron-proton double injection" from PVP to a-WO3 in the coloration process and greatly improves the photochromic responses. The coloration times can be as short as tens of seconds and the erasure times can be as long as 10 days in ambient conditions. As-formed photochromic membranes are low-cost, environmental benign and easy for large-scale production, indicate their great potential as flexible rewritable media for practical usage.

Low temperature plasma for the preparation of crater walls for compositional depth profiling of thin inorganic multilayers

An indirect, compositional depth profiling of an inorganic multilayer system using a helium low temperature plasma (LTP) containing 0.2% (v/v) SF6 was evaluated. A model multilayer system consisting of four 10 nm layers of silicon separated by four 50 nm layers of tungsten was plasma-etched for (10, 20, and 30) s at substrate temperatures of (50, 75, and 100) °C to obtain crater walls with exposed silicon layers that were then visualized using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to determine plasma-etching conditions that produced optimum depth resolutions. At a substrate temperature of 100 °C and an etch time of 10 s, the FWHM of the 2nd, 3rd, and 4th Si layers were (6.4, 10.9, and 12.5) nm, respectively, while the 1/e decay lengths were (2.5, 3.7, and 3.9) nm, matching those obtained from a SIMS depth profile. Though artifacts remain that contribute to degraded depth resolutions, a few experimental parameters have been identified that could be used to reduce their contributions. Further studies are needed, but as long as the artifacts can be controlled, plasma etching was found to be an effective method for preparing samples for compositional depth profiling of both organic and inorganic films, which could pave the way for an indirect depth profile analysis of inorganic-organic hybrid structures that have recently evolved into innovative next-generation materials.

In Situ Synthesis of Metal Nanoparticle Embedded Hybrid Soft Nanomaterials.

The allure of integrating the tunable properties of soft nanomaterials with the unique optical and electronic properties of metal nanoparticles has led to the development of organic-inorganic hybrid nanomaterials. A promising method for the synthesis of such organic-inorganic hybrid nanomaterials is afforded by the in situ generation of metal nanoparticles within a host organic template. Due to their tunable surface morphology and porosity, soft organic materials such as gels, liquid crystals, and polymers that are derived from various synthetic or natural compounds can act as templates for the synthesis of metal nanoparticles of different shapes and sizes. This method provides stabilization to the metal nanoparticles by the organic soft material and advantageously precludes the use of external reducing or capping agents in many instances. In this Account, we exemplify the green chemistry approach for synthesizing these materials, both in the choice of gelators as soft material frameworks and in the reduction mechanisms that generate the metal nanoparticles. Established herein is the core design principle centered on conceiving multifaceted amphiphilic soft materials that possess the ability to self-assemble and reduce metal ions into nanoparticles. Furthermore, these soft materials stabilize the in situ generated metal nanoparticles and retain their self-assembly ability to generate metal nanoparticle embedded homogeneous organic-inorganic hybrid materials. We discuss a remarkable example of vegetable-based drying oils as host templates for metal ions, resulting in the synthesis of novel hybrid nanomaterials. The synthesis of metal nanoparticles via polymers and self-assembled materials fabricated via cardanol (a bioorganic monomer derived from cashew nut shell liquid) are also explored in this Account. The organic-inorganic hybrid structures were characterized by several techniques such as UV-visible spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Utilization of silver nanoparticle-based hybrid nanomaterials as an antimicrobial material is another illustration of the advantage of hybrid nanomaterials. We envision that the results summarized in this Account will help the scientific community to design and develop diverse organic-inorganic hybrid materials using environmentally benign methods and that these materials will yield advanced properties that have multifaceted applications in various research fields.

Study on QPVA/TEOS hybrid anion membrane functionalized with quaternary ammonium groups for adsorption of Rhodamine B from aqueous solutions

Quaternized poly(vinyl alcohol)/tetraethoxysilane hybrid membranes were prepared and their adsorbability for Rhodamine B from aqueous solution was investigated. Experimental parameters, which will affect Rhodamine B sorption, such as tetraethoxysilane contents, pH, contact time, initial concentration and temperature were studied. The research results revealed that adsorption effect of Rhodamine B was enhanced by the formation of organic–inorganic hybrid structure and the grafting of quaternary ammonium groups. The fitting result of kinetic data was revealed that the pseudo-second-order model best described the adsorption of Rhodamine B. The equilibrium data were fitted by three isotherm models, and the Temkin model gave the best fit result based on the adsorption equilibrium data. Also, the adsorption free energy showed that the mechanism of Rhodamine B adsorption onto the membrane was chemisorption. Thermodynamic parameters calculation results revealed that the adsorption process of Rhodamine B onto the hybrid membrane was endothermic and spontaneous. Moreover, the hybrid membrane was successfully utilized for successive five cycles for the adsorption–desorption of Rhodamine B.

Near-infrared sensitive organic–inorganic photorefractive device

Organic–inorganic hybrid structure, assembled by Rh-doped Bi12TiO20 crystal and liquid crystal (LC) layer, operating at near-infrared range is proposed and demonstrated. Due to the photorefractive properties of inorganic substrate, light illumination caused a space charge field which acts as a driving force for LC molecules re-alignment and subsequent refractive index modulation. All optically controlled phase retardation ability has been demonstrated supporting possibilities for further infrared applications.

Synthesis of inorganic-organic hybrid membranes consisting of triazole linkages formed by the azide-alkyne click reaction

Inorganic-organic hybrid membranes consisting of aliphatic main chains and triazole rings were synthesized via copolymerization of a methacryloxysiloxane derivative with phosphonic acrylate, followed by hydrolysis. Hydroxyethyl methacrylate acid phosphate (HEMAP) was copolymerized with 3-methacryloxypropylmethyl-dimethoxysilane (MPMDMS), and then reacted with diethyl (4-(1-(3-(trimethoxysilyl)propyl)-1,2,3-triazol-4-yl)phenyl)phosphonate (TMSTAzPP), yielding inorganic-organic hybrid composites. The triazole ring of TMSTAzPP was constructed via the azide-alkyne click reaction using nanoporous Cu. IR, 13C, and 29Si NMR spectroscopy supported the formation of the inorganic-organic hybrid structure including a triazole ring. The membranes showed good thermal stability up to 180°C. The conductivity of the HEMAP/MPMDMS/TMSTAzPP membrane with a composition of 7:1:3 was higher than that of the HEMAP/MPMDMS membrane with a composition of 10:1. The conductivities of the 12:1:3 membranes at 130°C were 1.05×10−1Scm−1 and 1.68×10−4Scm−1 at 100% and 19.3% relative humidities (RHs), respectively. The power density of the 12:1:3 membrane was 3.9mWcm−2 at 140°C and 30% RH.

A strategy for the synthesis of cyclomatrix-polyphosphazene nanoparticles from non-aromatic monomers

Cyclomatrix-polyphosphazenes (C-PPZs) are a new class of nanomaterials that have attracted significant interest owing to their unique inorganic–organic hybrid structure and tunable properties.

Synthesis and characterization of TiO2 thin films for DSSC prototype

Third generation solar cells aim at reducing cost and/or increase the efficiency of the present solar cells. One such attractive approach is moving towards hybrid optoelectronic systems such as Dye Sensitized Solar Cells (DSSCs) which consists of an inorganic-organic hybrid structures. The aim of this paper is to study systematically a DSSC prototype built on an ITO substrate with TiO2 layer sensitized using a natural dye and a counter electrode. The different morphologies of TiO2 obtained using Sol-gel routes and other wet chemical routes, the influence of different weight percentages and surfactants would be analysed for optoelectronic properties. The most optimized layer is incorporated in making the hybrid optoelectronic system (DSSC). The incorporation of natural dye as sensitizer is an added advantage for the bio-degradability and for a sustainable development.

One-pot synthesis of proton-conductive inorganic–organic hybrid membranes from organoalkoxysilane and phosphonic acid derivatives

Inorganic–organic hybrid membranes consisting of an aliphatic main-chain polymer and Si–O linkages were synthesized via a simple one-pot process from an alkoxysilane derivative, methyl-substituted phenylvinylphosphonic acid, and phosphonic acid acrylate. (Methyldimethoxysilylmethyl)styrene (MDMSMS) was copolymerized with 3-methylphenylvinylphosphonic acid (CH3C6H4VPA, or MPVPA), and 2-hydroxyethyl methacrylate acid phosphate (HEMAP), and then hydrolyzed, yielding inorganic–organic hybrid composites. The formation of the inorganic–organic hybrid structure was confirmed by IR, 13C, and 29Si NMR spectroscopy. The membranes exhibited good thermal stability up to 180°C. The combination of aliphatic chains of the methacrylate derivative and Si–O networks in the hybrid membranes improved the mechanical properties of the membranes, enabling the construction of a membrane electrode assembly. The tensile modulus of the MDMSMS/MPVPA/HEMAP membrane with a composition of 1:1:5 was 688MPa. The conductivity of the 1:1:5 membranes was 4.1×10−2Scm−1 at 130°C and 100% relative humidity (RH), while it was 4.7×10−4Scm−1 at 130°C and 19.3% RH. The peak power of the 1:1:5 membrane was 4.8mW/cm2 at 140°C and 30% RH. The cell utilizing the hybrid membrane was operated at 120°C and 30% RH for 24h without any drop in cell voltage.

Formation of CdS in Supramolecular Dendrimer–Dye Assemblies: Electrostatic and Electrostatic-Coordination Templating

A novel concept for the formation of organic–inorganic hybrid nanostructures based on a tunable supramolecular templating mechanism involving several types of noncovalent interactions is presented. Different organic–inorganic hybrid structures with narrow size distributions composed of a cationic dendrimer, an oppositely charged divalent diazo dye, and CdS can be created: First, larger supramolecular structures consisting of several 100 to 1000 dendrimers is built based on ionic and π–π interaction. Second, with this self-assembled template, the hybrid nanostructure forms based on electrostatics and coordination interaction. The influence on shape and internal structure of the supramolecular hybrid architectures was investigated. A size control of the assemblies is possible in a range of 60–420 nm. The prospect to direct self-assembly and templating through the controlled combination of different noncovalent interactions potentially allows to create tailor-made systems for various applications.

An Interfacial Europium Complex on SiO2 Nanoparticles: Reduction-Induced Blue Emission System.

In this study, Eu-coated SiO2 nanoparticles have been prepared, consisting of an interfacial complex of Eu and 1,10-phenanthroline (phen) at the solid surfaces of the SiO2/Eu nanostructures. The as-prepared SiO2/Eu/phen nanoparticles exhibits sharp red emission via energy transfer from the phen to the EuIII. After sintering at 200 °C in air, the emission is tuned from red to blue. The blue emission is originated from EuII. This reduction-induced emissive phenomenon resulted from the electron-donating environment created by the surrounding phen and SiO2, which is the first reported fabrication of a stable EuII-based emissive material using mild conditions (reaction in air and at low temperature) and an organic-inorganic hybrid nanostructure. The existence of two different stable oxidation states with characteristic emissions, blue emissive EuII and red emissive EuIII, suggests significant potential applications as novel luminescent materials with inorganic-organic hybrid structures.

Polyurethane/polyhedral oligomeric silsesquioxane shape memory nanocomposites with low trigger temperature and quick response

Ester-based polyurethane (PU) was found to have excellent shape memory properties with low trigger temperature. Polyhedral oligomeric silsesquioxanes (POSS) have drawn considerable interest due to their hybrid organic–inorganic structures consisting of a silica cage surrounded by eight organic groups. Incorporation of functional POSS in polymers normally improves the mechanical properties of polymer matrix. For the purpose of obtaining shape memory materials with low trigger temperature and quick response, octa(3-hydroxypropyl) polyhedral oligomeric silsesquioxane (POSS-(OH)8) was incorporated into polyurethane by solution casting. The chemical structures and microstructures were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD) and field emission scanning electron microscope (FESEM). The thermal properties and dynamic mechanical properties were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The mechanical properties were also evaluated. Shape memory properties were characterized by cyclic thermal mechanical tests and physical shape recovery tests. The results show that the nanocomposites with low POSS-(OH)8 loading content (1 and 3 wt.%) possess higher breaking strength and elastic modulus, resulting in higher shape fixity, recovery ratios and faster recovery. The nanocomposites might have potential applications for controlling tags or proof marks in the area of low temperature storage.

Bio-inspired adhesion: Fabrication of molecularly imprinted nanocomposite membranes by developing a hybrid organic–inorganic nanoparticles composite structure

Inspired from the highly bioadhesive performance of mussel protein, a straightforward synthetic method for highly dense imprinting of artemisinin (Ars) was developed to prepare bio-inspired porous molecularly imprinted nanocomposite membranes (MINCMs). The key design for the successful synthesis of MINCMs is the formation of an organic–inorganic hybrid structure at the surface of polydopamine-modified regenerated cellulose membranes (PDA@RCMs). In this regard, the polydopamine coating surfaces could be used as a versatile platform for the further coating of inorganic nanoparticles. After a bio-inspired adhesion process, a larger active surface area and layered structure could be obtained at the surface of PDA@RCMs, hence promoting the preparation of the novel MINCMs with excellent perm-selectivity performance and regeneration ability. Moreover, the as-prepared MINCMs not only exhibited an outstanding adsorption capacity (54mgg−1), but also showed an excellent perm-selectivity (separation factor β is 15.03) toward Ars, which is promising for Ars separation and purification.

Proton-conductive inorganic–organic hybrid membranes synthesized from a trimethoxysilylmethylstyrene–fluorophenylvinyl acid copolymer

Inorganic–organic hybrid membranes composed of Si–O networks and an aliphatic main-chain polymer backbone were synthesized from an alkoxysilane derivative and an F-substituted phenylvinylphosphonic acid via copolymerization and sol–gel reaction. Thus, (trimethoxysilylmethyl)styrene (TMSMS) was copolymerized with 3-fluorophenyl- vinylphosphonic acid (FC6H4VPA), and the product was hydrolyzed to afford an inorganic–organic hybrid composite. Spectroscopic analysis revealed that the inorganic–organic hybrid structure was constructed via the polymerization of TMSMS and FC6H4VPA and the condensation of methoxy-Si bonds. The membranes showed good thermal stability up to 180°C, and it was found that the aliphatic chains bound to the F-substituted aromatic rings and the Si–O linkages in the hybrid membranes improved their mechanical properties. In addition, the proton conductivity of the membranes depended on the P/Si ratio of the product and increased as the P content increased. Notably, the conductivity at 130°C for the hybrid membrane synthesized with a TMSMS/FC6H4VPA ratio of 1/6 was 1.6×10−3Scm−1 and 6.4×10−2Scm−1 at low and 100% relative humidity (RH), respectively, while its power density at 140°C and 30% RH was 3.0mW/cm2.

A supramolecular 3-D organic-inorganic hybrid structure based on {PMo12} layers arranged in an alternating mode

Abstract An organic-inorganic hybrid compound based on {PMo12} layers, [Ag(pz)2]6[PMo12O40]2·3H2O 1 (pz = pyrazole), has been hydrothermally synthesized and characterized by elemental analysis, TG, IR spectroscopy, and single-crystal X-ray diffraction. Two crystallographically independent [PMo12O40]3– clusters are arranged in an AB–AB mode to give two kinds of supramolecular layers. The layers are further connected in a special alternating mode by [Ag(pz)2]+ linkers to form complex 3-D supramolecular network. Compound 1 exhibits good electrocatalytic activity in the reduction of hydrogen peroxide and shows fluorescence in the solid state at room temperature.