Articles de revues : « Semiconducting Hybrid Structures »

1

Zhang, Dao Hua. « Semiconducting Materials for Photonic Technology ». Materials Science Forum 859 (mai 2016) : 96–103. http://dx.doi.org/10.4028/www.scientific.net/msf.859.96.

Texte intégral

Résumé :

Semiconducting materials are important photonic materials and the technologies developed have been utilized in many fields of the modern society and they are closely related to the quality of our life. The main applications of the materials are for light source and sensing originated from interaction of photons and matters. In this invited talk, I will first present our work on the properties of the semiconducting materials and their applications as lasers and photodetectors, and then present integrated hybrid subwavelength structures which show significant enhancement on device performance. It is believed that complex hybrid structures which combine quantum-and hetero-structures made of semiconducting materials, and subwavelength structure for performance enhancement are the main focus in the near future.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Jung, Soon-Won, Jae Bon Koo, Chan Woo Park, Bock Soon Na, Ji-Young Oh et Sang Seok Lee. « Fabrication of Stretchable Organic–Inorganic Hybrid Thin-Film Transistors on Polyimide Stiff-Island Structures ». Journal of Nanoscience and Nanotechnology 15, n^o 10 (1 octobre 2015) : 7526–30. http://dx.doi.org/10.1166/jnn.2015.11151.

Texte intégral

Résumé :

In this study, stretchable organic–inorganic hybrid thin-film transistors (TFTs) are fabricated on a polyimide (PI) stiff-island/elastomer substrate using blends of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and poly(methyl methacrylate) (PMMA) and oxide semiconductor In-Ga-Zn-O as the gate dielectric and semiconducting layer, respectively. Carrier mobility, Ion/Ioff ratio, and subthreshold swing (SS) values of 6.1 cm2 V−1 s−1, 107, and 0.2 V/decade, respectively, were achieved. For the hybrid TFTs, the endurable maximum strain without degradation of electrical properties was approximately 49%. These results correspond to those obtained in the first study on fabrication of stretchable hybrid-type TFTs on elastomer substrate using an organic gate insulator and oxide semiconducting active channel structure, thus indicating the feasibility of a promising device for stretchable electronic systems.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Park, Kyoung-Won, et Alexie M. Kolpak. « Photocatalytic hydrogen evolution activity of Co/CoO hybrid structures : a first-principles study on the Co layer thickness effect ». Journal of Materials Chemistry A 7, n^o 27 (2019) : 16176–89. http://dx.doi.org/10.1039/c9ta04508b.

Texte intégral

Résumé :

Interfaces formed at metal/semiconductor hybrid system have the peculiar electronic characteristics depending on the thickness of metal layer. The different characteristics tune light responses of the metallic and semiconducting layers, resulting in various photocatalytic hydrogen evolution activities in the hybrid system.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Escalera-López, D., E. Gómez et E. Vallés. « Electrochemical growth of CoNi and Pt–CoNi soft magnetic composites on an alkanethiol monolayer-modified ITO substrate ». Physical Chemistry Chemical Physics 17, n^o 25 (2015) : 16575–86. http://dx.doi.org/10.1039/c5cp02291f.

Texte intégral

Résumé :

CoNi and Pt–CoNi magnetic layers on indium-tin oxide (ITO) substrates modified by an alkanethiol self-assembled monolayer (SAM) have been electrochemically obtained as an initial stage to prepare semiconducting layer-SAM-magnetic layer hybrid structures.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Dennington, Adam J., et Mark T. Weller. « Synthesis, structure and optoelectronic properties of hybrid iodobismuthate & ; iodoantimonate semiconducting materials ». Dalton Transactions 47, n^o 10 (2018) : 3469–84. http://dx.doi.org/10.1039/c7dt04280a.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Hoang, Thi Hong Cam, Thanh Binh Pham, Thuy Van Nguyen, Van Dai Pham, Huy Bui, Van Hoi Pham, Elena Duran et al. « Hybrid Integrated Nanophotonic Silicon-based Structures ». Communications in Physics 29, n^o 4 (16 décembre 2019) : 481. http://dx.doi.org/10.15625/0868-3166/29/4/13855.

Texte intégral

Résumé :

We report nanophotonic silicon-based devices for hybrid integration: 1D photonic crystal (PhC) on optical fiber, i. e. fiber Bragg grating (FBG) sensing probe integrated in fiber laser structure for chemical sensors and slotted planar 2D PhC cavity combined with carbon nanotube (CNT) towards light nanosources. The experiments have been carried out by integrating 1D PhC on optical fiber in fiber laser structure. This structure possesses many advantages including high resolution for wavelength shift, high optical signal-to-noise ratio (OSNR) of about 50~dB, the small full width at half-maximum (FWHM) of about 0.014~nm therefore its accuracy is enhanced, as well as the precision and capability are achieved for remote sensing. Low nitrate concentration in water from 0 to 80 ppm has been used to demonstrate its sensing ability in the experiment. The proposed sensor can work with good repeatability, rapid response, and its sensitivity can be obtained of \(3.2\times 10^{ - 3}\) nm/ppm with the limit of detection (LOD) of 3~ppm. For 2D PhC cavity, enhancement of photoluminescence of CNT emission is observed. The semiconducting single-walled carbon nanotubes (s-SWNTs) solution was prepared by polymer-sorted method and coupled with the confined modes in silicon slotted PhC cavities. The enhancement ratio of 1.15 is obtained by comparing between the PL peaks at two confined modes of the cavity. The PL enhancement result of the integrated system shows the potential for the realization of on-chip nanoscale sources.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Khan, Yeasin, Yohan Ahn, Jung Hwa Seo et Bright Walker. « Ionic moieties in organic and hybrid semiconducting devices : influence on energy band structures and functions ». Journal of Materials Chemistry C 8, n^o 40 (2020) : 13953–71. http://dx.doi.org/10.1039/d0tc03398g.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

BAI, J., et X. C. ZENG. « SILICON-BASED HALF-METAL : METAL-ENCAPSULATED SILICON NANOTUBE ». Nano 02, n^o 02 (avril 2007) : 109–14. http://dx.doi.org/10.1142/s179329200700043x.

Texte intégral

Résumé :

We performed first-principles calculation to show that a host–guest silicon nanostructure can exhibit half-metallic properties, wherein the host is a single-walled hexagonal silicon nanotube while the guest is a hybrid atomic chain of Mn and Co (encapsulated in the host nanotube). The calculated electronic band structures indicate that the Fermi level intersects only in the spin-up band, whereas the spin-down band exhibits semiconducting characteristics.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Al-Khaldi, Amal, Mohamed M. Fadlallah, Fawziah Alhajri et Ahmed A. Maarouf. « Hybrid G/BN@2H-MoS2 Nanomaterial Composites : Structural, Electronic and Molecular Adsorption Properties ». Nanomaterials 12, n^o 24 (7 décembre 2022) : 4351. http://dx.doi.org/10.3390/nano12244351.

Texte intégral

Résumé :

Hybrid structures often possess superior properties to those of their component materials. This arises from changes in the structural or physical properties of the new materials. Here, we investigate the structural, electronic, and gas-adsorption properties of hybrid structures made from graphene/hexagonal boron nitride and 2H-molybdenum disulfide (G/BN@MoS2) monolayers. We consider hybrid systems in which the G/BN patch is at the Mo plane (model I) and the S plane (model II). We find that the implanted hexagon of G or BN in MoS2 alters its electronic properties: G@MoS2 (I,II) are metallic, while BN@MoS2 (I) is an n-type conducting and BN@MoS2 (II) is semiconducting. We study the molecular adsorption of some diatomic gases (H2, OH, N2, NO, CO), triatomic gases (CO2, NO2, H2S, SO2), and polyatomic gases (COOH, CH4, and NH3) on our hybrid structures while considering multiple initial adsorption sites. Our results suggest that the hybrid systems may be suitable materials for some applications: G@MOS2 (I) for oxygen reduction reactions, BN@MoS2 (I,II) for NH3-based hydrogen production, and G@MoS2 (I) and BN@MoS2 (I,II) for filtration of No, Co, SO2, H2S, and NO2.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Zhao, Chuan, Changlong Xiao, Hubert M. Chan et Xunyu Lu. « Decorating Semiconductor Silver-Tetracyanoquinodimethane Nanowires with Silver Nanoparticles from Ionic Liquids ». Australian Journal of Chemistry 67, n^o 2 (2014) : 213. http://dx.doi.org/10.1071/ch13393.

Texte intégral

Résumé :

Hybrid semiconducting silver-tetracyanoquinodimethane (AgTCNQ) nanowires decorated with Ag nanoparticles have been synthesized at room temperature in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Hydroquinone was applied to reduce Ag+ and TCNQ to silver nanoparticles, and TCNQ–, respectively, under ambient conditions. AgTCNQ nanowires were formed via spontaneous electrolysis between Ag metal nanoparticles and TCNQ, and reaction between Ag+ and TCNQ–. Microscopic, spectroscopic, and X-ray characterizations all confirmed the formation of crystalline Ag nanoparticle–AgTCNQ nanowire hybrid structures. The ionic liquid was used as a reaction medium, but also as a stabilizing (or blocking) agent to control the nucleation and growth rate of AgTCNQ wires.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Jeong, Hoon-Seok, Dongeon Kim, Seungin Jee, Min-Jae Si, Changjo Kim, Jung-Yong Lee, Yujin Jung et Se-Woong Baek. « Colloidal Quantum Dot:Organic Ternary Ink for Efficient Solution-Processed Hybrid Solar Cells ». International Journal of Energy Research 2023 (6 février 2023) : 1–14. http://dx.doi.org/10.1155/2023/4911750.

Texte intégral

Résumé :

The fabrication of heterostructures via solution process is one of the essential technologies for realizing efficient advanced-generation optoelectronics. Hybrid structures comprising colloidal quantum dots (CQD) and organic semiconducting molecules are garnering considerable research interest because of their complementing optical and electrical properties. However, blending both the materials and forming a stable electronic ink are a challenge owing to the solubility mismatch. Herein, a CQD:organic ternary-blended hybrid solar ink is devised, and efficient hybrid solar cells are demonstrated via single-step spin coating under ambient conditions. Specifically, the passivation of the benzoic acid ligand on the CQD surface enables the dissolution in low-polar solvent such as chlorobenzene, which yields a stable CQD:organic hybrid ink. The hybrid ink facilitates the formation of favorable thin-film morphologies and, consequently, improves the charge extraction efficiency of the solar cells. The resulting hybrid solar cells exhibit a power conversion efficiency of 15.24% that is the highest performance among all existing air-processed CQD:organic hybrid solar cells.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Kang, Won-Seok, Taegon Oh, Gwang-Hyeon Nam, Hyo-Sop Kim, Ki-Suk Kim, Sun-Hyun Park, Jae-Ho Kim et Jae-Hyeok Lee. « Template-Assisted Electrochemical Synthesis of CdSe Quantum Dots—Polypyrrole Composite Nanorods ». Applied Sciences 10, n^o 17 (28 août 2020) : 5966. http://dx.doi.org/10.3390/app10175966.

Texte intégral

Résumé :

Luminescent nanoparticles have reached a high level of maturity in materials and spectral tunability for optics and optoelectronics. However, the lack of facile methodology for heterojunction formation of the nanoparticles provides many challenges for scalability. In this paper we demonstrate a simple procedure to synthesize a nanoparticle-embedded polymer nanorod hybrid structure via a template-based electrochemical method using anodic aluminum oxide membranes. This method enables the formation of interactive nanostructures wherein the interface area between the two components is maximized. As a proof of concept, semiconducting CdSe nanoparticles were embedded in polypyrrole nanorods with dimensions that can be finely tuned. We observed enhanced photoluminescence of the hybrid structures compared with bare polypyrrole nanorods.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Moulaoui, Lhouceine, Omar Bajjou, Abdelhafid Najim et Khalid Rahmani. « The study of electronic and optical properties of perovskites CH₃NH₃PbCl₃ and CH₃NH₃PbBr₃ using first-principle ». E3S Web of Conferences 336 (2022) : 00015. http://dx.doi.org/10.1051/e3sconf/202233600015.

Texte intégral

Résumé :

At present, Organic-inorganic hybrid methylammonium lead halide perovskites MAPbX3 (MA= CH3NH3; X = Cl, Br) have recently attract attention scientific researchers, as a promising candidate for photovoltaic and optoelectronic devices. We have studied the electronic structures and optical properties of perovskites CH3NH3PbBr3 and CH3NH3PbCl3, using density functional theory (DFT). These physical properties are calculated by CASTEP code, such as the band structures, total density of states (TDOS), absorption coefficient, refractive index and optical conductivity. The analysis of band gap shows that these two perovskites are semiconducting materials. Calculated absorption coefficient of CH3NH3PbBr3 and CH3NH3PbCl3 shows an absorption peak around 3.87 eV and 2.04 eV, respectively. The above results provide good agreement with experimental work for optoelectronic properties of CH3NH3PbBr3 and CH3NH3PbCl3 materials.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Almalki, Samira, LePing Yu, Tom Grace, Abdulaziz S. R. Bati et Joseph G. Shapter. « Preparation of Hybrid Molybdenum Disulfide/Single Wall Carbon Nanotube–n-Type Silicon Solar Cells ». Applied Sciences 10, n^o 1 (30 décembre 2019) : 287. http://dx.doi.org/10.3390/app10010287.

Texte intégral

Résumé :

Carbon nanotube/silicon (CNT/Si) heterojunction solar cells represent one new architecture for photovoltaic devices. The addition of MoS2 to the devices is shown to increase the efficiency of the devices. Two structures are explored. In one case, the single wall carbon nanotubes (SWCNTs) and MoS2 flakes are mixed to make a hybrid, which is then used to make a film, while in the other case, a two layer system is used with the MoS2 deposited first followed by the SWCNTs. In all cases, the solar cell efficiency is improved largely due to significant increases in the fill factor. The rise in fill factor is due to the semiconducting nature of the MoS2, which helps with the separation of charge carriers.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Hara, Shinjiro, Shinya Sakita et Masatoshi Yatago. « Selective-Area Growth and Electrical Characterization of Hybrid Structures between Semiconducting GaAs Nanowires and Ferromagnetic MnAs Nanoclusters ». Japanese Journal of Applied Physics 51 (20 novembre 2012) : 11PE01. http://dx.doi.org/10.1143/jjap.51.11pe01.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

16

Hara, Shinjiro, Shinya Sakita et Masatoshi Yatago. « Selective-Area Growth and Electrical Characterization of Hybrid Structures between Semiconducting GaAs Nanowires and Ferromagnetic MnAs Nanoclusters ». Japanese Journal of Applied Physics 51, n^o 11S (1 novembre 2012) : 11PE01. http://dx.doi.org/10.7567/jjap.51.11pe01.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

17

Mandal, Saumen, Gangadhar Purohit et Monica Katiyar. « Inkjet Printed Organic Thin Film Transistors : Achievements and Challenges ». Materials Science Forum 736 (décembre 2012) : 250–74. http://dx.doi.org/10.4028/www.scientific.net/msf.736.250.

Texte intégral

Résumé :

Inkjet printing of organic thin film transistors is an enabling technology for many applications requiring low cost electronics such as RFID tags, sensors, e-paper, and displays. This review summarizes the achievements and remaining challendges in the field. An all inkjet printed organic thin film transistor is feasible, but manufacturability needs to be improved. Often, a hybrid process in which only some layers are inkjet printed is used. Development of devices requires optimization of (1) ink chemistry, (2) inkjet process, (3) substrate ink interaction, and (4) new device structures. Several conducting, dielectric and semiconducting materials have been used to formulate ink. It appears that metal nanoparticle based conducting ink and PEDOT:PSS are widely used materials to fabricate source, drain and gate electrodes. PVPh is the most popular dielectric material for inkjet printing. To print semiconducting layer, both polymers and oligomers/small molecules are used. Many high performance organic semiconductors are p-type, but few n-type organic semiconductors show excellent performance. In addition to improved materials, challenges inherent in the inkjet process also need solutions. These are registration, alignment of the source,and drain with gate, resolution, reducing off-state current, and roll-to-roll processing.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Zhang, Lihui, Tiantian Kang, Fanghua Zhao, Duanliang Wang, Chuanying Shen et Jiyang Wang. « Growth and Property Investigations of Two Organic–Inorganic Hybrid Molecular Crystals with High Thermal Stability : 4-Iodoanilinium perchlorate 18-crown-6 and 4-Iodoanilinium Borofluorate 18-crown-6 ». Crystals 9, n^o 4 (15 avril 2019) : 207. http://dx.doi.org/10.3390/cryst9040207.

Texte intégral

Résumé :

Two new organic–inorganic hybrid molecular single crystals, 4-Iodoanilinium perchlorate 18-crown-6 (1) and 4-Iodoanilinium borofluorate 18-crown-6 (2), with large sizes and high thermal stability were successfully synthesized by solution method. Their structures, phase purities, thermal stability, dielectric, absorption and fluorescence spectra were systematically investigated for potential applications. Compounds 1 and 2 crystallize in orthorhombic crystal system, in same space group, namely Pnma. The thermal measurements shown 1 and 2 maintain high thermal stability up to 150 °C. The temperature dependency of dielectric constant was studied, and no distinct anomaly was observed. The band gap were calculated to be 3.38 eV and 3.57 eV for 1 and 2, respectively, slightly smaller than those of layer perovskite (benzylammonium)2PbCl4 semiconducting materials, which have potential applications in optoelectronic detection field. The investigations throw light on the semiconductor properties of organic–inorganic hybrid crown type material and provide two types of crown compounds with high thermal stability.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Murakami, Hiroto, et Naotoshi Nakashima. « Soluble Carbon Nanotubes and Their Applications ». Journal of Nanoscience and Nanotechnology 6, n^o 1 (1 janvier 2006) : 16–27. http://dx.doi.org/10.1166/jnn.2006.17900.

Texte intégral

Résumé :

Carbon nanotubes (CNTs) have been the forefront of nanoscience and nanotechnology due to their unique electrical and mechanical properties and specific functions. However, due to their poor solubility in solvents, the applications using the materials have been limited. Therefore, strategic approaches toward the solubilization of CNTs are important in wide fields including chemistry, physics, biochemistry, biology, pharmaceuticals, and medical sciences. In this article, we summarize: (i) the strategic approaches toward the solubilization of CNTs using chemical and physical modifications, (ii) nanocomposites of CNTs and biological molecules including DNA, (iii) formation of CNTs with topological structures, (iv) separation of metallic and semiconducting nanotubes, (v) the preparations of films and fibers of CNTs and hybrid materials of CNTs and organic and inorganic molecules.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Zagorac, Jelena, Dejan Zagorac, Vesna Šrot, Marjan Ranđelović, Milan Pejić, Peter A. van Aken, Branko Matović et J. Christian Schön. « Synthesis, Characterization, and Electronic Properties of ZnO/ZnS Core/Shell Nanostructures Investigated Using a Multidisciplinary Approach ». Materials 16, n^o 1 (29 décembre 2022) : 326. http://dx.doi.org/10.3390/ma16010326.

Texte intégral

Résumé :

ZnO/ZnS core/shell nanostructures, which are studied for diverse possible applications, ranging from semiconductors, photovoltaics, and light-emitting diodes (LED), to solar cells, infrared detectors, and thermoelectrics, were synthesized and characterized by XRD, HR-(S)TEM, and analytical TEM (EDX and EELS). Moreover, band-gap measurements of the ZnO/ZnS core/shell nanostructures have been performed using UV/Vis DRS. The experimental results were combined with theoretical modeling of ZnO/ZnS (hetero)structures and band structure calculations for ZnO/ZnS systems, yielding more insights into the properties of the nanoparticles. The ab initio calculations were performed using hybrid PBE0 and HSE06 functionals. The synthesized and characterized ZnO/ZnS core/shell materials show a unique three-phase composition, where the ZnO phase is dominant in the core region and, interestingly, the auxiliary ZnS compound occurs in two phases as wurtzite and sphalerite in the shell region. Moreover, theoretical ab initio calculations show advanced semiconducting properties and possible band-gap tuning in such ZnO/ZnS structures.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Kopasov, Alexander A., Ivan M. Khaymovich et Alexander S. Mel'nikov. « Inverse proximity effect in semiconductor Majorana nanowires ». Beilstein Journal of Nanotechnology 9 (16 avril 2018) : 1184–93. http://dx.doi.org/10.3762/bjnano.9.109.

Texte intégral

Résumé :

We study the influence of the inverse proximity effect on the superconductivity nucleation in hybrid structures consisting of semiconducting nanowires placed in contact with a thin superconducting film and discuss the resulting restrictions on the operation of Majorana-based devices. A strong paramagnetic effect for electrons entering the semiconductor together with spin–orbit coupling and van Hove singularities in the electronic density of states in the wire are responsible for the suppression of superconducting correlations in the low-field domain and for the reentrant superconductivity at high magnetic fields in the topologically nontrivial regime. The growth of the critical temperature in the latter case continues up to the upper critical field destroying the pairing inside the superconducting film due to either orbital or paramagnetic mechanism. The suppression of the homogeneous superconducting state near the boundary between the topological and non-topological regimes provides the conditions favorable for the Fulde–Ferrel–Larkin–Ovchinnikov instability.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Jayanand, Kishan, et Anupama B. Kaul. « Plexcitonic interactions in spherical and bi-pyramidical Au nanoparticles with monolayer WSe₂ ». Applied Physics Letters 121, n^o 20 (14 novembre 2022) : 201108. http://dx.doi.org/10.1063/5.0120636.

Texte intégral

Résumé :

Plasmons associated with zero-dimensional (0D) metal nanoparticles and their synergistic interactions with excitons in two-dimensional (2D) semiconductors offer opportunities for remarkable spectral tunability not otherwise evident in the pristine parent materials. As a result, an in-depth study elucidating the nature of the plasmonic and excitonic interactions, jointly referred to as plexcitons, is critical to understanding the foundational aspects of the light–matter interactions in hybrid 0D–2D systems. In this work, our focal point is to examine the plexcitonic interactions of van der Waals (vdWs) hybrid structures composed of 2D WSe2 and 0D Au nanoparticles (Au-NPs) in their spherical (Au-Sp) and bi-pyramidical (Au-BP) architectures. The geometry-dependent surface plasmon resonance (SPR) peaks in Au-Sp and Au-BP nanoparticles were deciphered using ultraviolet-visible (UV-Vis) optical absorption spectroscopy, while photoluminescence spectroscopy revealed the excitonic behavior in the vapor synthesized monolayer (1L) WSe2 as well as the Au-Sp/WSe2 and Au-BP/WSe2 hybrids. Furthermore, our temperature-dependent and wavelength-dependent optoelectronic transport measurements showed a shift in the spectral response of 1L WSe2 toward the SPR peak locations of Au-Sp and Au-BP, mediated via the plexciton interactions. Models for the plexcitonic interactions are proposed, which provide a framework to explain the photoexcited hot charge carrier injection from AuNPs to WSe2 and their influence on carrier dynamics. Our findings demonstrate that geometry-mediated response of the AuNPs provides another degree of freedom to modulate the carrier photodynamics in WSe2, which can also be useful for tailoring the optoelectronic performance of the broader class of semiconducting 2D materials.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Vassilyeva, Olga Yu, Elena A. Buvaylo, Oksana V. Nesterova, Alexandre N. Sobolev et Dmytro S. Nesterov. « New Low-Dimensional Organic–Inorganic Lead Halide Hybrid Systems Directed by Imidazo[1,5-a]pyridinium-Based Cation or Imines : Synthesis, Structures, Non-Covalent Interactions and Optical Properties ». Crystals 13, n^o 2 (13 février 2023) : 307. http://dx.doi.org/10.3390/cryst13020307.

Texte intégral

Résumé :

The organic–inorganic lead halide hybrids comprising semiconducting perovskite components and organic modules have proven to be promising candidates for optoelectronic applications. The modulation of the inorganic components as optical centres by diverse organic cationic templates is under intense investigation. Herein, we successfully prepared new one-dimensional lead halide hybrid perovskites [L1]2n[Pb2Cl6]n∞·nH2O (1) and [PbBr2(L2)]n∞·0.5nH2O (2), and the dimeric complex [PbBr2(L3)]2 (3) in water media. In 1, 2-(2-hydroxyethyl)-2H-imidazo[1,5-a]pyridinium cation [L1]+ resulted from the oxidative condensation–cyclization between formaldehyde, ethanolamine and 2-pyridinecarbaldehyde (2-PCA); the polydentate Schiff base ligands L2 and L3 formed in the in situ condensation of 2-PCA and ethanolamine or ethylenediamine, respectively. The lead chloride hybrid 1 contains the previously unreported type of a [Pb2Cl6]∞ double chain constructed from three-edge- and five-edge-sharing PbCl6 octahedra, and cations forming π-bonded stacks aligned along the inorganic wires. In the crystal of 2, pairs of the double-side organically decorated [PbBr2(L2)]∞ chains built of corner-sharing PbBr3N2O octahedra arrange hydrophilic channels to host water molecules. In the solid state, the identically stacked dimers of 3 form columns parallel to the ab plane with the Pb2Br4 moieties in the column being strictly coplanar. Hirshfeld surface analysis was used to rationalize the packing patterns through hydrogen bonds of O−H···O/Cl and C−H···O/Cl types with the involvement of OH groups of [L1]+, L2 and water molecules in 1 and 2, as well as C–H∙∙∙Br hydrogen bonding in 2 and 3. The QTAIM analysis of non-covalent interactions in 1–3 was performed. According to the analysis of the solid-state UV–visible reflectance spectra by a Tauc plot, the optical band gap values of 1, 2 and 3 as direct gap semiconductors were estimated to be 3.36, 3.13 and 2.96 eV, respectively.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Beregoi, Mihaela, Nicoleta Preda, Andreea Costas, Monica Enculescu, Raluca Negrea, Horia Iovu et Ionut Enculescu. « Synthesis of Core–Double Shell Nylon-ZnO/Polypyrrole Electrospun Nanofibers ». Nanomaterials 10, n^o 11 (12 novembre 2020) : 2241. http://dx.doi.org/10.3390/nano10112241.

Texte intégral

Résumé :

Core–double shell nylon-ZnO/polypyrrole electrospun nanofibers were fabricated by combining three straightforward methods (electrospinning, sol–gel synthesis and electrodeposition). The hybrid fibrous organic–inorganic nanocomposite was obtained starting from freestanding nylon 6/6 nanofibers obtained through electrospinning. Nylon meshes were functionalized with a very thin, continuous ZnO film by a sol–gel process and thermally treated in order to increase its crystallinity. Further, the ZnO coated networks were used as a working electrode for the electrochemical deposition of a very thin, homogenous polypyrrole layer. X-ray diffraction measurements were employed for characterizing the ZnO structures while spectroscopic techniques such as FTIR and Raman were employed for describing the polypyrrole layer. An elemental analysis was performed through X-ray microanalysis, confirming the expected double shell structure. A detailed micromorphological characterization through FESEM and TEM assays evidenced the deposition of both organic and inorganic layers. Highly transparent, flexible due to the presence of the polymer core and embedding a semiconducting heterojunction, such materials can be easily tailored and integrated in functional platforms with a wide range of applications.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Hubička, Zdenek, Martin Zlámal, Jiri Olejníček, Drahoslav Tvarog, Martin Čada et Josef Krýsa. « Semiconducting p-Type Copper Iron Oxide Thin Films Deposited by Hybrid Reactive-HiPIMS + ECWR and Reactive-HiPIMS Magnetron Plasma System ». Coatings 10, n^o 3 (3 mars 2020) : 232. http://dx.doi.org/10.3390/coatings10030232.

Texte intégral

Résumé :

A reactive high-power impulse magnetron sputtering (r-HiPIMS) and a reactive high-power impulse magnetron sputtering combined with electron cyclotron wave resonance plasma source (r-HiPIMS + ECWR) were used for the deposition of p-type CuFexOy thin films on glass with SnO2F conductive layer (FTO). The aim of this work was to deposit CuFexOy films with different atomic ratio of Cu and Fe atoms contained in the films by these two reactive sputtering methods and find deposition conditions that lead to growth of films with maximum amount of delafossite phase CuFeO2. Deposited copper iron oxide films were subjected to photoelectrochemical measurement in cathodic region in order to test the possibility of application of these films as photocathodes in solar hydrogen production. The time stability of the deposited films during photoelectrochemical measurement was evaluated. In the system r-HiPIMS + ECWR, an additional plasma source based on special modification of inductively coupled plasma, which works with an electron cyclotron wave resonance ECWR, was used for further enhancement of plasma density ne and electron temperature Te at the substrate during the reactive sputtering deposition process. A radio frequency (RF) planar probe was used for the determination of time evolution of ion flux density iionflux at the position of the substrate during the discharge pulses. Special modification of this probe to fast sweep the probe system made it possible to determine the time evolution of the tail electron temperature Te at energies around floating potential Vfl and the time evolution of ion concentration ni. This plasma diagnostics was done at particular deposition conditions in pure r-HiPIMS plasma and in r-HiPIMS with additional ECWR plasma. Generally, it was found that the obtained ion flux density iionflux and the tail electron temperature Te were systematically higher in case of r-HiPIMS + ECWR plasma than in pure r-HiPIMS during the active part of discharge pulses. Furthermore, in case of hybrid discharge plasma excitation, r-HiPIMS + ECWR plasma has also constant plasma density all the time between active discharge pulses ni ≈ 7 × 1016 m−3 and electron temperature Te ≈ 4 eV, on the contrary in pure r-HiPIMS ni and Te were negligible during the “OFF” time between active discharge pulses. CuFexOy thin films with different atomic ration of Cu/Fe were deposited at different conditions and various crystal structures were achieved after annealing in air, in argon and in vacuum. Photocurrents in cathodic region for different achieved crystal structures were observed by chopped light linear voltammetry and material stability by chronoamperometry under simulated solar light and X-ray diffraction (XRD). Optimization of depositions conditions results in the desired Cu/Fe ratio in deposited films. Optimized r-HiPIMS and r-HiPIMS + ECWR plasma deposition at 500 °C together with post deposition heat treatment at 650 °C in vacuum is essential for the formation of stable and photoactive CuFeO2 phase.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Márquez, J., M. De la Cruz-Guzmán, L. F. Cházaro et G. Palestino. « Porous Silicon Nanostructured Materials for Sensing Applications : Molecular Assembling and Electrochemical or Optical Evaluation ». MRS Proceedings 1812 (2016) : 77–82. http://dx.doi.org/10.1557/opl.2016.21.

Texte intégral

Résumé :

ABSTRACTPorous silicon (PSi) combines the potential of miniaturization with a very large surface area. The PSi surface can be chemically modified resulting in a high sensitivity (low detection threshold) device for chemical and biomolecular sensing. In previous work, we have shown that redox proteins and fluorescent ligands can be infiltrated into PSi (PSiMc) structures. The hybrid devices have shown interesting new properties produced by the coupling of the individual properties of PSi nanostructures and the modifiers. In this work, we have obtained a PSiMc/redox protein bioelectrode, which presents a quasi-reversible electrochemical response. This effect was attributed to the semiconducting nature of the PSi substrate and to the functional groups of the crosslinking molecules (MPTS), which together produce a capacitive effect on the device. On the other hand, the chemical modification of PSiMc with fluorescent ligands allowed us to fabricate fluorescent PSi hybrid nanostructures, which were tested for the detection of environmental pollutants such as heavy metals (specifically Hg2+). We found that the selectivity of this optical device depends on the selected recognizing molecule. The captured metal induces the formation of a metallic complex that shows higher fluorescence compared with the sensor device. These results demonstrate the viability of using porous silicon as optical sensors and electrochemical biosensors. The infiltration of fluorescent recognizing molecules and proteins into the PSi matrix were evaluated by specular reflectance, FTIR spectroscopy, fluorescence spectroscopy and cyclic voltammetry.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Li, Yujing, Wei Gao, Fei Wang, Dehe Zhao, Yuyuan Zhang et Hong Yin. « Self-Ordered Orientation of Crystalline Hexagonal Boron Nitride Nanodomains Embedded in Boron Carbonitride Films for Band Gap Engineering ». Coatings 9, n^o 3 (12 mars 2019) : 185. http://dx.doi.org/10.3390/coatings9030185.

Texte intégral

Résumé :

Boron carbonitride (BCN) films containing hybridized bonds involving elements B, C, and N over wide compositional ranges enable an abundant variety of new materials, electronic structures, properties, and applications, owing to their semiconducting properties with variable band gaps. However, it still remains challenging to achieve band gap-engineered BCN ternary with a controllable composition and well-established ordered structure. Herein, we report on the synthesis and characterization of hybridized BCN materials, consisting of self-ordered hexagonal BN (h-BN) crystalline nanodomains, with its aligned basal planes preferentially perpendicular to the substrate, depending on the growth conditions. The observation of the two sets of different band absorptions suggests that the h-BN nanodomains are distinguished enough to resume their individual band gap identity from the BCN films, which decreases as the carbon content increases in the BCN matrix, due to the doping and/or boundary effect. Our results reveal that the structural features and band gap of this form of hybrid BCN films are strongly correlated with the kinetic growth factors, making it a great system for further fundamental physical research and for potential in the development of band gap-engineered applications in optoelectronics.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Bein, Thomas. « Zeolitic Host–Guest Interactions and Building Blocks for the Self-Assembly of Complex Materials ». MRS Bulletin 30, n^o 10 (octobre 2005) : 713–20. http://dx.doi.org/10.1557/mrs2005.269.

Texte intégral

Résumé :

AbstractOrdered nanoscale pore systems such as those represented by zeolites offer many opportunities for the design of complex functional systems via self-assembly.With their large internal surface areas and tunable, well-defined crystalline pore structures that allow molecular sieving and ion exchange, zeolites can be adapted for numerous applications. The nanoscale reactors present in zeolite pore systems have been explored as structural templates for the spatial organization of numerous guests. Examples from various fields are discussed, such as the stabilization of organic dyes for the construction of energy transfer and storage systems, the construction of host–guest hybrid catalyst systems, and the encapsulation of conducting or semiconducting nanoscale wires and clusters. More complex, hierarchical forms of nanostructured matter become accessible when zeolite crystals are used as building blocks for the selfassembly of thin films or three-dimensional objects. A combination of weaker and stronger interactions ranging from dispersive forces, hydrogen bonding, and electrostatic interactions to covalent bonding can be used to build functional hierarchical constructs. Several examples and novel applications of such systems will be discussed, including oriented channel systems, chemical sensors, and hierarchical pore systems for catalytic reactions.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Varadwaj, Arpita, Pradeep R. Varadwaj, Helder M. Marques et Koichi Yamashita. « The Pnictogen Bond, Together with Other Non-Covalent Interactions, in the Rational Design of One-, Two- and Three-Dimensional Organic-Inorganic Hybrid Metal Halide Perovskite Semiconducting Materials, and Beyond ». International Journal of Molecular Sciences 23, n^o 15 (8 août 2022) : 8816. http://dx.doi.org/10.3390/ijms23158816.

Texte intégral

Résumé :

The pnictogen bond, a somewhat overlooked supramolecular chemical synthon known since the middle of the last century, is one of the promising types of non-covalent interactions yet to be fully understood by recognizing and exploiting its properties for the rational design of novel functional materials. Its bonding modes, energy profiles, vibrational structures and charge density topologies, among others, have yet to be comprehensively delineated, both theoretically and experimentally. In this overview, attention is largely centered on the nature of nitrogen-centered pnictogen bonds found in organic-inorganic hybrid metal halide perovskites and closely related structures deposited in the Cambridge Structural Database (CSD) and the Inorganic Chemistry Structural Database (ICSD). Focusing on well-characterized structures, it is shown that it is not merely charge-assisted hydrogen bonds that stabilize the inorganic frameworks, as widely assumed and well-documented, but simultaneously nitrogen-centered pnictogen bonding, and, depending on the atomic constituents of the organic cation, other non-covalent interactions such as halogen bonding and/or tetrel bonding, are also contributors to the stabilizing of a variety of materials in the solid state. We have shown that competition between pnictogen bonding and other interactions plays an important role in determining the tilting of the MX6 (X = a halogen) octahedra of metal halide perovskites in one, two and three-dimensions. The pnictogen interactions are identified to be directional even in zero-dimensional crystals, a structural feature in many engineered ordered materials; hence an interplay between them and other non-covalent interactions drives the structure and the functional properties of perovskite materials and enabling their application in, for example, photovoltaics and optoelectronics. We have demonstrated that nitrogen in ammonium and its derivatives in many chemical systems acts as a pnictogen bond donor and contributes to conferring stability, and hence functionality, to crystalline perovskite systems. The significance of these non-covalent interactions should not be overlooked, especially when the focus is centered on the rationale design and discovery of such highly-valued materials.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Ghosal, Sanghamitra, et Partha Bhattacharyya. « ZnO/RGO Heterojunction Based near Room Temperature Alcohol SENSOR with Improved Efficiency ». Engineering Proceedings 6, n^o 1 (17 mai 2021) : 25. http://dx.doi.org/10.3390/i3s2021dresden-10073.

Texte intégral

Résumé :

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application in various fields, including chemical sensors. The concomitant optimization of the surface attributes (varying different dimensions) of ZnO have become a sensation for the entire research community. Moreover, the small thickness and extremely large surface of exfoliated 2D nanosheets render the gas sensing material an ideal candidate for achieving strong coupling with different gas molecules. However, temperature is a crucial factor in the field of chemical sensing. Recently, graphene-based gas sensors have attracted attention due to their variety of structures, unique sensing performances and room temperature working conditions. In this work, a highly sensitive and fast responsive low temperature (60 °C)-based ethanol sensor, based on RGO/2D ZnO nanosheets hybrid structure, is reported. After detailed characterizations, the vapor sensing potentiality of this sensor was tested for the detection of ethanol. The ethanol sensor offered the response magnitude of 89% (100 ppm concentration) with response and recovery time of 12 s/29 s, respectively. Due to excessively high number of active sites for VOC interaction, with high yield synthesis process and appreciably high carrier mobility, this has paved the way for developing future generation, miniaturized and flexible (wearable) vapor sensor devices, meeting the multidimensional requirements for traditional and upcoming (health/medical sector) applications. The underlying mechanistic framework for vapor sensing, using this hybrid junction, is explained with the Energy Band Diagram.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Tarasov, Anton S., Ivan A. Tarasov, Ivan A. Yakovlev, Mikhail V. Rautskii, Ilya A. Bondarev, Anna V. Lukyanenko, Mikhail S. Platunov et al. « Asymmetric Interfaces in Epitaxial Off-Stoichiometric Fe3+xSi1−x/Ge/Fe3+xSi1−x Hybrid Structures : Effect on Magnetic and Electric Transport Properties ». Nanomaterials 12, n^o 1 (31 décembre 2021) : 131. http://dx.doi.org/10.3390/nano12010131.

Texte intégral

Résumé :

Three-layer iron-rich Fe3+xSi1−x/Ge/Fe3+xSi1−x (0.2 < x < 0.64) heterostructures on a Si(111) surface with Ge thicknesses of 4 nm and 7 nm were grown by molecular beam epitaxy. Systematic studies of the structural and morphological properties of the synthesized samples have shown that an increase in the Ge thickness causes a prolonged atomic diffusion through the interfaces, which significantly increases the lattice misfits in the Ge/Fe3+xSi1−x heterosystem due to the incorporation of Ge atoms into the Fe3+xSi1−x bottom layer. The resultant lowering of the total free energy caused by the development of the surface roughness results in a transition from an epitaxial to a polycrystalline growth of the upper Fe3+xSi1−x. The average lattice distortion and residual stress of the upper Fe3+xSi1−x were determined by electron diffraction and theoretical calculations to be equivalent to 0.2 GPa for the upper epitaxial layer with a volume misfit of −0.63% compared with a undistorted counterpart. The volume misfit follows the resultant interatomic misfit of |0.42|% with the bottom Ge layer, independently determined by atomic force microscopy. The variation in structural order and morphology significantly changes the magnetic properties of the upper Fe3+xSi1−x layer and leads to a subtle effect on the transport properties of the Ge layer. Both hysteresis loops and FMR spectra differ for the structures with 4 nm and 7 nm Ge layers. The FMR spectra exhibit two distinct absorption lines corresponding to two layers of ferromagnetic Fe3+xSi1−x films. At the same time, a third FMR line appears in the sample with the thicker Ge. The angular dependences of the resonance field of the FMR spectra measured in the plane of the film have a pronounced easy-axis type anisotropy, as well as an anisotropy corresponding to the cubic crystal symmetry of Fe3+xSi1−x, which implies the epitaxial orientation relationship of Fe3+xSi1−x (111)[0−11] || Ge(111)[1−10] || Fe3+xSi1−x (111)[0−11] || Si(111)[1−10]. Calculated from ferromagnetic resonance (FMR) data saturation magnetization exceeds 1000 kA/m. The temperature dependence of the electrical resistivity of a Ge layer with thicknesses of 4 nm and 7 nm is of semiconducting type, which is, however, determined by different transport mechanisms.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Bafekry, A., M. Faraji, S. Karbasizadeh, H. R. Jappor, I. Abdolhosseini Sarsari, M. Ghergherehchi et D. Gogova. « Investigation of vacancy defects and substitutional doping in AlSb monolayer with double layer honeycomb structure : a first-principles calculation ». Journal of Physics : Condensed Matter 34, n^o 6 (18 novembre 2021) : 065701. http://dx.doi.org/10.1088/1361-648x/ac360a.

Texte intégral

Résumé :

Abstract The experimental knowledge of the AlSb monolayer with double layer honeycomb structure is largely based on the recent publication (Le Qin et al 2021 ACS Nano 15 8184), where this monolayer was recently synthesized. Therefore, the aim of our research is to consequently explore the effects of substitutional doping and vacancy point defects on the electronic and magnetic properties of the novel hexagonal AlSb monolayer. Besides experimental reports, the phonon band structure and cohesive energy calculations confirm the stability of the AlSb monolayer. Its direct bandgap has been estimated to be 0.9 eV via the hybrid functional method, which is smaller than the value of 1.6 eV of bulk material. The majority of vacancy defects and substitutional dopants change the electronic properties of the AlSb monolayer from semiconducting to metallic. Moreover, the MgSb impurity has demonstrated the addition of ferromagnetic behavior to the material. It is revealed through the calculation of formation energy that in Al-rich conditions, the vacant site of VSb is the most stable, while in Sb-rich circumstances the point defect of VAl gets the title. The formation energy has also been calculated for the substitutional dopants, showing relative stability of the defected structures. We undertook this theoretical study to inspire many experimentalists to focus their efforts on AlSb monolayer growth incorporating different impurities. It has been shown here that defect engineering is a powerful tool to tune the properties of novel AlSb two-dimensional monolayer for advanced nanoelectronic applications.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Hubler, Graham K. « Pulsed Laser Deposition ». MRS Bulletin 17, n^o 2 (février 1992) : 26–29. http://dx.doi.org/10.1557/s0883769400040586.

Texte intégral

Résumé :

Research on materials grown by pulsed laser deposition, or PLD, has experienced phenomenal growth since late 1987 when T. Venkatesan (one of the authors for this issue) and co-workers pointed out that extreme nonequilibrium conditions created by pulsed laser melting of YBaCuO allowed in-situ preparation of thin films of this high transition temperature (Tc) superconducting material. Since then, PLD has emerged as the primary means for high throughput deposition of high-quality superconducting thin films for research and devices. This probably came as no surprise to J.T. Cheung (another of this issue's authors), who performed original research in this area and tirelessly labored during the 1980s to convince a skeptical audience of the advantages of PLD.Along with the success of PLD in the arena of high-temperature superconductivity, however, is the explosion of activity in the deposition of many other materials, made possible by the unique features of pulsed laser deposition, materials previously not amenable to in-situ thin film growth. Creative minds reasoned that since PLD can deposit a demanding, complex material such as the perovskite structure Y1Ba2Cu3O7-δ, why not other perovskites or multicomponent oxide materials? It also turns out that the range of properties of multicomponent oxides is virtually limitless. They can be metallic, insulating, semiconducting, biocompatable, superconducting, ferroelectric, piezoelectric, and so on. One is not limited to the properties of elements or binary compounds on which the electronics and microelectronics industries are based. Indeed, in a recent review of hybrid ferromagnetic- semiconductor structures, G. Prinz states, “… there has been little work devoted to incorporating magnetic materials into planar integrated electronic (or photonic) circuitry there are potential applications that have no analog in vacuum electronics but that remain unrealized, awaiting the development of appropriate materials and processing procedures.” In pulsed laser deposition, we may well have in hand the “appropriate processing procedure” to deposit sequential epitaxial layers of high quality materials that possess profoundly different properties.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Bukhari, Syed Nizam Uddin Shah, Aqeel Ahmed Shah, Muhammad Ali Bhatti, Aneela Tahira, Iftikhar Ahmed Channa, Abdul Karim Shah, Ali Dad Chandio et al. « Psyllium-Husk-Assisted Synthesis of ZnO Microstructures with Improved Photocatalytic Properties for the Degradation of Methylene Blue (MB) ». Nanomaterials 12, n^o 20 (12 octobre 2022) : 3568. http://dx.doi.org/10.3390/nano12203568.

Texte intégral

Résumé :

Wastewater from the textile industry is chronic and hazardous for the human body due to the presence of a variety of organic dyes; therefore, its complete treatment requires efficient, simple, and low cost technology. For this purpose, we grew ZnO microstructures in the presence of psyllium husk, and the role of psyllium husk was to modify the surface of the ZnO microstructures, create defects in the semiconducting crystal structures, and to alter the morphology of the nanostructured material. The growth process involved a hydrothermal method followed by calcination in air. Additionally, the psyllium husk, after thermal combustion, added a certain value of carbon into the ZnO nanomaterial, consequently enhancing the photocatalytic activity towards the degradation of methylene blue. We also investigated the effect of varying doses of photocatalyst on the photocatalytic properties towards the photodegradation of methylene blue in aqueous solution under the illumination of ultraviolet light. The structure and morphology of the prepared ZnO microstructures were explored by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. The degradation of methylene blue was monitored under the irradiation of ultraviolet light and in the dark. Also, the degradation of methylene blue was measured with and without photocatalyst. The photodegradation of methylene blue is highly increased using the ZnO sample prepared with psyllium husk. The photodegradation efficiency is found to be approximately 99.35% for this sample. The outperforming functionality of psyllium-husk-assisted ZnO sample is attributed to large surface area of carbon material from the psyllium husk and the synergetic effect between the incorporated carbon and ZnO itself. Based on the performance of the hybrid material, it is safe to say that psyllium husk has high potential for use where surface roughness, morphology alteration, and defects in the crystal structure are vital for the enhancing the functionality of a nanostructured material. The observed performance of ZnO in the presence of psyllium husk provides evidence for the fabrication of a low cost and efficient photocatalyst for the wastewater treatment problems.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Fiechter, Sebastian, Fanxing Xi, Farabi Bozheyev, Fatwa Firdaus Abdi, Klaus Ellmer, Peter Bogdanoff et Moritz Kölbach. « (Invited) On the Role of Electrocatalysts in the Process of Light-Driven Water Splitting ». ECS Meeting Abstracts MA2018-01, n^o 31 (13 avril 2018) : 1854. http://dx.doi.org/10.1149/ma2018-01/31/1854.

Texte intégral

Résumé :

Due to its high energy density, hydrogen could play an important role to store chemical energy in GW scale. To produce it in large quantities, “artificial leaf”-type structures can be used to convert solar light into hydrogen by photoelectrochemical splitting of water. Since this process is most efficiently working under acidic conditions, acid-stable semiconducting materials are required to efficiently absorb sunlight and generate electron-hole pairs, the energy of which must be high enough to split water. In addition, cheap and abundant electrocatalysts are needed to minimize the overvoltages at cathode and anode. To replace costly platinum as well as RuO2 as efficient electrocatalysts for hydrogen and oxygen evolution, resp., alternative catalysts such as MoCo, (Mo,Co)Sx and (NH4)2Mo3S13 for pH <7 [1] and amorphous CoOxOHy, Mn2O3 for pH >7 [2] have been tested as hydrogen (HE) and oxygen evolution (OE) catalysts, respectively. The materials were first deposited on conductive glass by reactive magnetron sputtering, spin coating or electrochemical deposition techniques and investigated electrochemically. Highest activity as HE catalysts was found by depositing (NH4)2Mo3S13 on amorphous MoSx/FTO and alloys of MoCo, while porous layers of Mn2O3 deposited on FTO glass showed high activity as OE catalyst. Due to their remarkable behavior as dark catalysts (η(Mn2O3) = 340 mV and η(MoSx) = -170 mV at j = 10 mA/cm2), the materials were afterwards deposited on p- and n-type photosensitive transition metal chalcogenide layers to investigate their behavior under illumination. Surprisingly, (NH4)2Mo3S13, deposited on highly 001-textured polycrystalline p-type WSe2 film, behaved as a photosensitive hydrogen evolving electrode. Here the deposited catalyst film operates as an electrocatalyst for hydrogen evolution, but also as a semiconductor at the catalyst-semiconductor interface forming a buried heterojunction. References: [1] Jesse D. Benck, Sang Chul Lee, Kara D. Fong, Jakob Kibsgaard, Robert Sinclair, Thomas F. Jaramillo, Adv. Energy Mater. 4 (2014) 1400739-1400739. [2] Bogdanoff P., Stellmach D., Gabriel O., Stannowski B., Schlatmann R., van de Krol R., Fiechter S, Energy Technology 4, (2016) 230–241, DOI:number:10.1002/ente.201500317 [3] Stellmach D., Bogdanoff P., Gabriel O., Stannowski B., Schlatmann R., van de Krol R, Fiechter S., Nanostructured MoS2 particles as a novel hydrogen evolving catalyst integrated in a PV-hybrid electrolyzer, Materials and Processes for Energy: Communicating, Current Research and Technological Developments, Vol. 1 (A. Méndez-Vilas, Ed.), FORMATEX 2013, 880-886. [4] Moritz Kölbach, Sebastian Fiechter, Roel van de Krol, Peter Bogdanoff, Catalysis Today, 290 (2017) 2–9, https://doi.org/10.1016/j.cattod.2017.03.030 [5] Ramírez A., Hillebrand, P., Stellmach D., May M.M., Bogdanoff P., Fiechter S.,Phys Chem. C, 118 (2014) 14073-14081 and SI.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Shi, Chenyuyi, Jun Peng, An Jin, Jin Leng, Xiaoyong He et Duo Cao. « Investigation of tunable Fano resonances based on the InSb metamaterials ». Modern Physics Letters B 35, n^o 14 (12 mars 2021) : 2150244. http://dx.doi.org/10.1142/s0217984921502444.

Texte intégral

Résumé :

Based on the hybrid semiconductive InSb metamaterials (MMs), we investigated the tunable Fano resonances in the terahertz regime, including the effects of carrier concentrations of InSb layer, environment temperatures and operation frequencies. The results manifested that an obvious Fano resonance was observed by using the heterostructure of InSb bars, the peak value of Fano resonance reached more than 0.97 with a high [Formula: see text]-factor of larger than 50. By changing the carrier concentrations of InSb layer, the propagation properties of semiconductor MM structures can be effectively modulated, the amplitude modulation of Fano resonance can reach more than 80%. The results are helpful for designing novel tunable terahertz devices with high [Formula: see text]-factor, e.g. modulators, sensors and antenna.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Moskwa, Marcin, Grażyna Bator, Magdalena Rok, Wojciech Medycki, Andrzej Miniewicz et Ryszard Jakubas. « Investigations of organic–inorganic hybrids based on homopiperidinium cation with haloantimonates(iii) and halobismuthates(iii). Crystal structures, reversible phase transitions, semiconducting and molecular dynamic properties ». Dalton Transactions 47, n^o 38 (2018) : 13507–22. http://dx.doi.org/10.1039/c8dt03121e.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

38

Kane, Aichata, Ivaylo Hinkov, Ovidiu Brinza, Mongia Hosni, Aliou Hamady Barry, Salim Mourad Cherif et Samir Farhat. « One-Step Synthesis of Graphene, Copper and Zinc Oxide Graphene Hybrids via Arc Discharge : Experiments and Modeling ». Coatings 10, n^o 4 (25 mars 2020) : 308. http://dx.doi.org/10.3390/coatings10040308.

Texte intégral

Résumé :

In this paper, we report on a modified arc process to synthetize graphene, copper and zinc oxide graphene hybrids. The anode was made of pure graphite or graphite mixed with metals or metal oxides. After applying a controlled direct current, plasma is created in the interelectrode region and the anode is consumed by eroding. Continuous and abundant flux of small carbon, zinc or copper species, issued from the anode at a relatively high temperature, flows through the plasma and condenses in the vicinity of a water-cooled cathode leading to few-layered graphene sheets and highly ordered carbon structures. When the graphite rod is filled with copper or zinc oxide nanoparticles, few layers of curved graphene films were anchored with spherical Cu and ZnO nanoparticles leading to a one-step process synthesis of graphene hybrids, which combine the synergetic properties of graphene along with nanostructured metals or semiconducting materials. The as-prepared samples were characterized by Raman spectroscopy, X-ray diffraction (XRD), spatially resolved electron energy loss spectroscopy (EELS), energy filtered elemental mapping and transmission electron microscopy (TEM). In addition to the experimental study, numerical simulations were performed to determine the velocity, temperature and chemical species distributions in the arc plasma under specific graphene synthesis conditions, thereby providing valuable insight into growth mechanisms.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Liu, Jia, Chun Fai Chan et Ming Gong. « Majorana fermions in semiconducting nanowire and Fulde–Ferrell superconductor hybrid structures ». Frontiers of Physics 14, n^o 1 (18 octobre 2018). http://dx.doi.org/10.1007/s11467-018-0863-2.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Asaithambi, Aswin, Nastaran Kazemi Tofighi, Michele Ghini, Nicola Curreli, P. James Schuck et Ilka Kriegel. « Energy transfer and charge transfer between semiconducting nanocrystals and transition metal dichalcogenide monolayers ». Chemical Communications, 2023. http://dx.doi.org/10.1039/d3cc01125a.

Texte intégral

Résumé :

Nowadays, as a result of the emergence of low-dimensional hybrid structures, the scientific community is interested in their interfacial carrier dynamics, including charge transfer and energy transfer. By combining the...

Styles APA, Harvard, Vancouver, ISO, etc.

41

Hähsler, Martin, Ingo Appel et Silke Behrens. « Magnetic hybrid materials in liquid crystals ». Physical Sciences Reviews, 3 décembre 2020. http://dx.doi.org/10.1515/psr-2019-0090.

Texte intégral

Résumé :

AbstractThe integration of nanoparticles with magnetic, ferroelectric or semiconducting properties into liquid crystals (LCs) has attracted great interest both for fundamental investigations and for technological applications. Here, an overview of hybrid materials based on magnetic nanoparticles (MNPs) and thermotropic LCs is given. After a general introduction to thermotropic LCs and LC-MNP hybrid materials, various preparation methods established by us are presented. The synthesis of shape-(an)isotropic MNPs, their functionalization by tailored (pro)mesogenic ligands with linear or dendritic structures and their integration into LC hosts are discussed. The characterization of the MNPs, (pro)mesogenic ligands and resulting MNP-LC hybrid materials is described to show the influence of MNP functionalization on the MNP-LC interactions including aspects such as colloidal stability and structuring in the LC host. Overall, we show that the physical properties of the hybrid material are significantly influenced not only by the MNPs (i.e., their size, shape and composition) but also by their surface properties (i.e., the structure of the (pro)mesogenic ligands).

Styles APA, Harvard, Vancouver, ISO, etc.

42

Guo, Gang, Yajuan Xu et Gencai Guo. « Janus-functionalization induced magnetism and improved optoelectronic properties in two-dimension silicene and germanene : insights from first-principles calculations ». Journal of Physics : Condensed Matter, 12 mai 2023. http://dx.doi.org/10.1088/1361-648x/acd50d.

Texte intégral

Résumé :

Abstract In this paper, the structural stability, optoelectronic and magnetic properties of silicene and germanene monolayers Janus-functionalized simultaneously with hydrogen and alkali metal atoms (Li and Na) are investigated systematically by using first-principles calculations. The calculated results of the AIMD simulations and cohesive energies indicate that all functionalized cases have good stability. Meanwhile, the calculated band structures show that all functionalized cases retain the Dirac cone. Particularly, the cases of HSiLi and HGeLi show metallic nature but retain semiconducting characteristics. Besides, the above two cases can present obvious magnetic behavior and their magnetic moments are mainly originated by the p states of Li atom. The metallic property and weak magnetic character can also be found in the case of HGeNa. While the case of HSiNa exhibits the nonmagnetic semiconducting property with a indirect band gap of 0.42 eV calculated by the HSE06 hybrid functional. It is also found that the optical absorption in the visible region of silicene and germanene can be effectively improved by Janus-functionalization. Specifically, a high optical absorption of visible light in an order of 4.5×105 cm−1 can be observed in the case of HSiNa. Furthermore, in the visible region, the reflection coefficients of all functionalized cases can also be enhanced. These results demonstrate the feasibility of the Janus-functionalization method to modulate the optoelectronic and magnetic properties of silicene and germanene, expanding their potential applications in the fields of spintronics and optoelectronics.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Xu, Jia-Le, Li-Wen Li, Yu-Xuan Luo, Sheng-Hao Yuan et Ning-Ning Liu. « Antifungal Nanomaterials : Current Progress and Future Directions ». Innovations in Digital Health, Diagnostics, and Biomarkers, 13 juillet 2020. http://dx.doi.org/10.36401/iddb-20-03.

Texte intégral

Résumé :

ABSTRACT Fungal infection poses a severe threat to human health worldwide resulting in a serious problem in clinic. Due to the limited arsenal of existing antifungal drugs, the nanomaterials were thus regarded as the candidate for developing new antifungal drugs. On the one hand, the antifungal nanomaterials are divided into inorganic nanomaterials, organic nanomaterials, and hybrid nanomaterials, among which inorganic nanoparticles include metal and semiconducting categories. On the other hand, they can also be divided into inorganic particles, organic structures, and mixed nanostructures. Currently various directions for the research and development of antifungal nanomaterials are undergoing. To improve the antifungal effect, the chemical modification of nanomaterials and combination with the available drugs are two strategies widely used. In addition, optimizing the synthetic process of nanomaterials is also a major method to broaden their antifungal application. This review focuses on the current research progress and cutting-edge technologies of antifungal nanomaterials in the field of pharmacodynamics, synthesis and combination of drugs. The nanomaterial will provide a promising and broadly effective antifungal strategy and represent a potentially repositionable candidate for the treatment of fungal infections.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Escribano, Samuel D., Andrea Maiani, Martin Leijnse, Karsten Flensberg, Yuval Oreg, Alfredo Levy Yeyati, Elsa Prada et Rubén Seoane Souto. « Semiconductor-ferromagnet-superconductor planar heterostructures for 1D topological superconductivity ». npj Quantum Materials 7, n^o 1 (18 août 2022). http://dx.doi.org/10.1038/s41535-022-00489-9.

Texte intégral

Résumé :

AbstractHybrid structures of semiconducting (SM) nanowires, epitaxially grown superconductors (SC), and ferromagnetic-insulator (FI) layers have been explored experimentally and theoretically as alternative platforms for topological superconductivity at zero magnetic field. Here, we analyze a tripartite SM/FI/SC heterostructure but realized in a planar stacking geometry, where the thin FI layer acts as a spin-polarized barrier between the SM and the SC. We optimize the system’s geometrical parameters using microscopic simulations, finding the range of FI thicknesses for which the hybrid system can be tuned into the topological regime. Within this range, and thanks to the vertical confinement provided by the stacking geometry, trivial and topological phases alternate regularly as the external gate is varied, displaying a hard topological gap that can reach half of the SC one. This is a significant improvement compared to setups using hexagonal nanowires, which show erratic topological regions with typically smaller and softer gaps. Our proposal provides a magnetic field-free planar design for quasi-one-dimensional topological superconductivity with attractive properties for experimental control and scalability.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Liu, Junyi, Gang Lu et Xu Zhang. « Exciton dispersion and exciton-phonon interaction in solids by time-dependent density functional theory ». Journal of Chemical Physics, 10 janvier 2023. http://dx.doi.org/10.1063/5.0137326.

Texte intégral

Résumé :

Understanding, predicting and ultimately controlling exciton band structure and exciton dynamics are central to diverse chemical and materials problems. Here, we have developed a first-principles method to determine exciton dispersion and exciton-phonon interaction in semiconducting and insulating solids based on time-dependent density functional theory (TDDFT). The first-principles method is formulated in planewave bases and pseudopotentials and can be used to compute exciton band structures, exciton charge density, ionic forces, non-adiabatic coupling matrix between excitonic states, and exciton-phonon coupling matrix. Based on the spinor formulation, the method enables self-consistent noncollinear calculations to capture spin-orbital coupling. Hybrid exchange-correlation functionals are incorporated to deal with long-range electron-hole interactions in solids. A sub-Hilbert space approximation is introduced to reduce the computational cost without loss of accuracy. For validations, we have applied the method to compute the exciton band structure and exciton-phonon coupling strength in transition metal dichalcogenide monolayers; both agree very well with previous GW-Bethe-Salpeter equation (BSE) and experimental results. This development paves the way for accurate determinations of exciton dynamics in a wide range of solid-state materials.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Semiconducting Hybrid Structures »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres