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

Materials ◽  
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.

Light Emitting thin Film Devices Based on Self-assembled Multilayer Heterostructures of PPV

1995 ◽  
Vol 413 ◽  
Author(s):  
M. Ferreira ◽  
O. Onitsuka ◽  
A. C. Fou ◽  
B. Hsieh ◽  
M. F. Rubner
Keyword(s):  
Thin Film ◽  
Carrier Transport ◽  
Thermal Conversion ◽  
Layer By Layer ◽  
Light Emitting ◽  
Hole Transporting ◽  
Improved Performance ◽  
And Performance ◽  
P Type ◽  
Thin Film Devices

ABSTRACTPPV based light emitting thin film devices were fabricated using a layer-by-layer deposition technique involving the alternate spontaneous adsorption of a PPV precursor polymer and either poly(styrene-4-sulfonate) (SPS) or poly(methacrylic acid) (PMA). It was demonstrated that the polyanion used to self-assemble the PPV precursor strongly influences the characteristics and performance of the resulting LEDs. Devices fabricated with PPV created in the presence of SPS exhibited symmetric I–V curves, low luminance levels and very high current densities while PPV/PMA devices exhibited luminance levels in the range of 10–60 cd/m2 and classical rectifying behavior. These dramatic differences are primarily due to a low level of p-type doping activated during the thermal conversion of PPV and/or during device operation that confers excellent hole carrier transport capabilities to the PPV/SPS combination. Fabrication of a multi-slab type heterostructure device comprised of a PPV/SPS block (hole transporting block) and a PPV/PMA block (emitting block) resulted in improved performance with luminance levels significantly higher than previously obtained for a single slab PPV/PMA device (typically > 100 cd/m2). It was also demonstrated that the presence of very thin (about 20–30 Å thick) insulating layers at the Al/polymer interface improves device efficiency by a factor of 2–4.

Study of Droplet Diffusion in Hydrothermal-Assisted Transient Jet Fusion of Ceramics

2020 ◽  
Author(s):  
Fan Fei ◽  
Li He ◽  
Levi Kirby ◽  
Xuan Song
Keyword(s):  
High Performance ◽  
Functional Materials ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Transient Solution ◽  
Powder Bed ◽  
Manufacturing Method ◽  
Precise Control ◽  
Powder Packing ◽  
Diffusion Profiles

Abstract Hydrothermal-assisted transient jet fusion (HTJF) is a powder-based additive manufacturing method of ceramics, which utilizes a water-mediated hydrothermal mechanism to fuse particles together, eliminating the use of organic binders in forming green bodies and thereby contributing to high green-density parts (> 90%) advantageous for fabricating functional materials with high-performance. In the HTJF process, a transient solution such as water is selectively deposited into a powder bed in a layer-by-layer fashion followed by a hydrothermal fusion process. Upon the ejection and deposition of a droplet of the transient solution on the surface of the powder bed, the diffusion behavior of the liquid significantly influences the particle fusion and the fabrication accuracy of the HTJF process. Precise control of the liquid diffusion in the powder bed is critical for the fabrication of ceramic structures with both high density and accuracy. In this paper, the dependence of transient solution diffusion on different process parameters (i.e., powder packing density, droplet size, pressure, etc.) in the HTJF process were studied. Both numerical modeling and experimental methods were used to quantify the relationships between processing parameters and diffusion profiles of transient solution droplets (e.g., diffusion width/depth). Optimum processing conditions were identified to mitigate the undesired diffusion of transient solution droplets in the powder bed.

Molecular design with silicon core: toward commercially available hole transport materials for high-performance planar p–i–n perovskite solar cells

2018 ◽  
Vol 6 (2) ◽  
pp. 404-413 ◽  
Author(s):  
Rongming Xue ◽  
Moyao Zhang ◽  
Guiying Xu ◽  
Jingwen Zhang ◽  
Weijie Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Molecular Design ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Hole Transport

We synthesized a low-cost silicon containing HTL materials, achieving an excellent PCE of 19.06% for planar p–i–n perovskite solar cells.

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

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 70 ◽  
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.

scholarly journals Printable, high-performance solid-state electrolyte films

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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