Layer‐by‐layer Growth of Preferred‐Oriented MOF Thin Film on Nanowire Array for High‐Performance Chemiresistive Sensing

AbstractThe layer-by-layer growth of film structures consisting of sequential depositions of oppositely charged polymers and macrocycles (ring-shaped molecules) have been constructed using molecular self-assembly techniques. These self-assembled thin films were characterized with X-ray reflectometry, which yielded (1) the average electron density, (2) the average thicknesses, and (3) the roughness of the growth surface of the self-assembled multilayer of macrocycles and polymers. These observations suggest that inorganic-organic interactions play an important role during the initial stages of thin-film growth, but less so as the thin film becomes thicker. Optical absorption techniques were also used to characterize the self-assembled multilayers. Phorphyrin and phthalocyanine derivatives were chosen as the building blocks of the self-assembled multilayers because of their interesting optical properties.

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A computational study of SrTiO3 thin film deposition: Morphology and growth modes

Journal of Materials Research ◽

10.1557/jmr.2009.0229 ◽

2009 ◽

Vol 24 (6) ◽

pp. 1994-2000 ◽

Cited By ~ 2

Author(s):

Jennifer L. Wohlwend ◽

Cosima N. Boswell ◽

Simon R. Phillpot ◽

Susan B. Sinnott

Keyword(s):

Thin Film ◽

Thin Films ◽

Computational Study ◽

Thin Film Deposition ◽

Layer Growth ◽

Film Deposition ◽

Layer By Layer ◽

Growth Modes ◽

Deposition Processes ◽

Dynamics Simulations

The growth of SrTiO3 (STO) thin films is examined using classical molecular dynamics simulations. First, a beam of alternating SrO and TiO2 molecules is deposited on the (001) surface of STO with incident kinetic energies of 0.1, 0.5, or 1.0 eV/atom. Second, deposition of alternating SrO and TiO2 monolayers, where both have incident energies of 1.0 eV/atom, is examined. The resulting thin film morphologies predicted by the simulations are compared to available experimental data. The simulations indicate the way in which the incident energy, surface termination, and beam composition influence the morphology of the thin films. On the whole, some layer-by-layer growth is predicted to occur on both SrO- and TiO2-terminated STO for both types of deposition processes, with the alternating monolayer approach yielding thin films with compositions that are much closer to that of bulk STO.

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Modification of Nanofiber Support Layer for Thin Film Composite forward Osmosis Membranes via Layer-by-Layer Polyelectrolyte Deposition

Membranes ◽

10.3390/membranes8030070 ◽

2018 ◽

Vol 8 (3) ◽

pp. 70 ◽

Cited By ~ 18

Author(s):

Ralph Gonzales ◽

Myoung Park ◽

Leonard Tijing ◽

Dong Han ◽

Sherub Phuntsho ◽

...

Keyword(s):

Thin Film ◽

High Performance ◽

Forward Osmosis ◽

Composite Membranes ◽

Structural Parameter ◽

Layer By Layer ◽

Film Composite ◽

Thin Film Composite ◽

Layer Deposition ◽

Tfc Membrane

Electrospun nanofiber-supported thin film composite membranes are among the most promising membranes for seawater desalination via forward osmosis. In this study, a high-performance electrospun polyvinylidenefluoride (PVDF) nanofiber-supported thin film composite (TFC) membrane was successfully fabricated after molecular layer-by-layer polyelectrolyte deposition. Negatively-charged electrospun polyacrylic acid (PAA) nanofibers were deposited on electrospun PVDF nanofibers to form a support layer consisted of PVDF and PAA nanofibers. This resulted to a more hydrophilic support compared to the plain PVDF nanofiber support. The PVDF-PAA nanofiber support then underwent a layer-by-layer deposition of polyethylenimine (PEI) and PAA to form a polyelectrolyte layer on the nanofiber surface prior to interfacial polymerization, which forms the selective polyamide layer of TFC membranes. The resultant PVDF-LbL TFC membrane exhibited enhanced hydrophilicity and porosity, without sacrificing mechanical strength. As a result, it showed high pure water permeability and low structural parameter values of 4.12 L m−2 h−1 bar−1 and 221 µm, respectively, significantly better compared to commercial FO membrane. Layer-by-layer deposition of polyelectrolyte is therefore a useful and practical modification method for fabrication of high performance nanofiber-supported TFC membrane.

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Printable, high-performance solid-state electrolyte films

Science Advances ◽

10.1126/sciadv.abc8641 ◽

2020 ◽

Vol 6 (47) ◽

pp. eabc8641

Author(s):

Weiwei Ping ◽

Chengwei Wang ◽

Ruiliu Wang ◽

Qi Dong ◽

Zhiwei Lin ◽

...

Keyword(s):

Thin Film ◽

Solid State ◽

High Performance ◽

Ionic Conductivities ◽

Amorphous Structure ◽

Uniform Structure ◽

Layer By Layer ◽

Solid State Electrolyte ◽

Solid State Batteries ◽

Rapid Sintering

Current ceramic solid-state electrolyte (SSE) films have low ionic conductivities (10−8 to 10−5 S/cm ), attributed to the amorphous structure or volatile Li loss. Herein, we report a solution-based printing process followed by rapid (~3 s) high-temperature (~1500°C) reactive sintering for the fabrication of high-performance ceramic SSE films. The SSEs exhibit a dense, uniform structure and a superior ionic conductivity of up to 1 mS/cm. Furthermore, the fabrication time from precursor to final product is typically ~5 min, 10 to 100 times faster than conventional SSE syntheses. This printing and rapid sintering process also allows the layer-by-layer fabrication of multilayer structures without cross-contamination. As a proof of concept, we demonstrate a printed solid-state battery with conformal interfaces and excellent cycling stability. Our technique can be readily extended to other thin-film SSEs, which open previously unexplores opportunities in developing safe, high-performance solid-state batteries and other thin-film devices.

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A Windmill-Shaped Molecule with Anthryl Blades to Form Smooth Hole-Transport Layers via a Photoprecursor Approach

Materials ◽

10.3390/ma13102316 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2316

Author(s):

Akihiro Maeda ◽

Aki Nakauchi ◽

Yusuke Shimizu ◽

Kengo Terai ◽

Shuhei Sugii ◽

...

Keyword(s):

Thin Film ◽

High Performance ◽

Molecular Design ◽

Layer Structure ◽

Hole Transport ◽

Layer By Layer ◽

Precise Control ◽

Wet Processing ◽

Improved Performance ◽

Controlled Deposition

Preparation of high-performance organic semiconductor devices requires precise control over the active-layer structure. To this end, we are working on the controlled deposition of small-molecule semiconductors through a photoprecursor approach wherein a soluble precursor compound is processed into a thin-film form and then converted to a target semiconductor by light irradiation. This approach can be applied to layer-by-layer solution deposition, enabling the preparation of p–i–n-type photovoltaic active layers by wet processing. However, molecular design principles are yet to be established toward obtaining desirable thin-film morphology via this unconventional method. Herein, we evaluate a new windmill-shaped molecule with anthryl blades, 1,3,5-tris(5-(anthracen-2-yl)thiophen-2-yl)benzene, which is designed to deposit via the photoprecursor approach for use as the p-sublayer in p–i–n-type organic photovoltaic devices (OPVs). The new compound is superior to the corresponding precedent p-sublayer materials in terms of forming smooth and homogeneous films, thereby leading to improved performance of p–i–n OPVs. Overall, this work demonstrates the effectiveness of the windmill-type architecture in preparing high-quality semiconducting thin films through the photoprecursor approach.

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