scholarly journals Acid Exfoliation of Imine-linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

2019 ◽  
Author(s):  
David Burke ◽  
Chao Sun ◽  
Ioannina Castano ◽  
Nathan C. Flanders ◽  
Austin Evans ◽  
...  
Keyword(s):  
Large Scale ◽  
Optoelectronic Devices ◽  
Charge Storage ◽  
Solution Processing ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Nanofiltration Membranes ◽  
Storage Devices ◽  
Crystalline Polymers ◽  
Promising Strategy

Covalent organic frameworks (COFs) are highly modular, porous, crystalline polymers of interest for charge storage devices, nanofiltration membranes, optoelectronic devices, and more. COFs are typically synthesized as microcrystalline powders, a morphology that limits their performance in these applications, and their limited solubility precludes large-scale processing into more useful morphologies and devices. Here, we report a general, scalable method to exfoliate two-dimensional imine-linked COF powders by temporarily protonating their linkages. The resulting suspensions were cast into continuous, crystalline COF films up to 10 cm in diameter. This strategy was successfully applied to three different COF structures, and excellent film thickness control (50 nm to 20 µm) was achieved by modifying the suspension composition, concentration, and casting protocol. Acid-mediated exfoliation is a promising strategy for solution processing readily accessible imine-linked COF powders into functional devices.

scholarly journals Acid Exfoliation of Imine-linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

2019 ◽  
Author(s):  
David Burke ◽  
Chao Sun ◽  
Ioannina Castano ◽  
Nathan C. Flanders ◽  
Austin Evans ◽  
...  
Keyword(s):  
Large Scale ◽  
Optoelectronic Devices ◽  
Charge Storage ◽  
Solution Processing ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Nanofiltration Membranes ◽  
Storage Devices ◽  
Crystalline Polymers ◽  
Promising Strategy

Covalent organic frameworks (COFs) are highly modular, porous, crystalline polymers of interest for charge storage devices, nanofiltration membranes, optoelectronic devices, and more. COFs are typically synthesized as microcrystalline powders, a morphology that limits their performance in these applications, and their limited solubility precludes large-scale processing into more useful morphologies and devices. Here, we report a general, scalable method to exfoliate two-dimensional imine-linked COF powders by temporarily protonating their linkages. The resulting suspensions were cast into continuous, crystalline COF films up to 10 cm in diameter. This strategy was successfully applied to three different COF structures, and excellent film thickness control (50 nm to 20 µm) was achieved by modifying the suspension composition, concentration, and casting protocol. Acid-mediated exfoliation is a promising strategy for solution processing readily accessible imine-linked COF powders into functional devices.

Surface Functionalization of Two-Dimensional Vertically Aligned Semiconductor Heterojunctions

2018 ◽  
Vol 765 ◽  
pp. 8-11
Author(s):  
Serge Zhuiykov ◽  
Zhen Yin Hai
Keyword(s):  
Large Scale ◽  
Atomic Layer ◽  
Thin Layers ◽  
General Strategy ◽  
Two Dimensional ◽  
Storage Devices ◽  
Energy Conversion And Storage ◽  
Vertically Aligned ◽  
2D Nanomaterials ◽  
Semiconductor Heterojunctions

Large-scale fabrication of two-dimensional (2D) nanomaterials by vapor phase depostion enabled the establishment of vertically aligned semiconductor herterojunctions. However, the property modulation of 2D semiconductor heterojunctions remains chanlleging within such thin layers. Herein, we proposed a general strategy towards the surface functionlization of 2D semiconductor heterojunctions simply by two-step atomic layer deposition (ALD) process with following post-annealing. TiO2-WO3 heterojunction was taken as a typical case in this work and its electrochemical properties were significantly improved via the proposed strategy. This strategy may open a new pathway for facile functionalization of 2D nanomaterials for the energy conversion and storage devices.

Batteries and charge storage devices based on electronically conducting polymers

2010 ◽  
Vol 25 (8) ◽  
pp. 1561-1574 ◽  
Author(s):  
Howard E. Katz ◽  
Peter C. Searson ◽  
Theodore O. Poehler
Keyword(s):  
Solar Cells ◽  
Conducting Polymers ◽  
Large Scale ◽  
Performance Metrics ◽  
Ionic Species ◽  
Charge Storage ◽  
Doping Density ◽  
Storage Devices ◽  
Doped Polymers ◽  
Electronically Conducting Polymers

Strong interest in energy generation and storage has yielded excellent progress on organic based solar cells, and there is also a strong desire for equivalent advancement in polymer-based charge storage devices such as batteries and super-capacitors. Despite extensive research on electronically conducting polymers including polypyrrole, polythiophene, and polyaniline, limitations to the maximum doping density and chemical stability had been considered a significant restriction on the development of polymer batteries. Recent work appears to show a meaningful increase in the upper bound of the maximum density from 0.5 to 1.0 electrons per monomer depending on the structure, processing, and ionic species used in charging and discharging of the polymers. Several recent examples have also implied that more stable, reversible charge-discharge cycling is being observed in n-doped polymers. These observations suggest that the performance metrics of this class of electronically conducting polymer may ultimately reach the levels required for practical battery applications. Further efforts are essential to perfect practical large-scale electrode fabrication to move toward greater compatibility in the methods used for solar cells and those used in producing batteries. A better understanding must also be developed to elucidate the effects of molecular structure and polymer architecture on these materials.

scholarly journals Comprehensive Performance Quasi-Non-Volatile Memory Compatible with Large-Scale Preparation by Chemical Vapor Deposition

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1471
Author(s):  
Kun Yang ◽  
Hongxia Liu ◽  
Shulong Wang ◽  
Wenlong Yu ◽  
Tao Han
Keyword(s):  
Power Dissipation ◽  
Large Scale ◽  
Electronic Devices ◽  
Charge Storage ◽  
Two Dimensional ◽  
Large Scale Preparation ◽  
Two Dimensional Materials ◽  
Non Volatile Memory ◽  
Scale Preparation ◽  
Volatile Memory

Two-dimensional materials with atomic thickness have become candidates for wearable electronic devices in the future. Graphene and transition metal sulfides have received extensive attention in logic computing and sensing applications due to their lower power dissipation, so that their processes have been relatively mature for large-scale preparation. However, there are a few applications of two-dimensional materials in storage, which is not in line with the development trend of integration of storage and computing. Here, a charge storage quasi-non-volatile memory with a lanthanum incorporation high-k dielectric for next-generation memory devices is proposed. Thanks to the excellent electron capture capability of LaAlO3, the MoS2 memory exhibits a very comprehensive information storage capability, including robust endurance and ultra-fast write speed of 1 ms approximately. It is worth mentioning that it exhibits a long-term stable charge storage capacity (refresh time is about 1000 s), which is 105 times that of the dynamic random access memory (refresh time is on a milliseconds timescale) so that the unnecessary power dissipation greatly reduces caused by frequent refresh. In addition, its simple manufacturing process makes it compatible with various current two-dimensional electronic devices, which will greatly promote the integration of two-dimensional electronic computing.

scholarly journals Two-Dimensional Nanograting Fabrication by Multistep Nanoimprint Lithography and Ion Beam Etching

2021 ◽  
Vol 1 (1) ◽  
pp. 39-48
Author(s):  
Janek Buhl ◽  
Danbi Yoo ◽  
Markus Köpke ◽  
Martina Gerken
Keyword(s):  
Electron Beam ◽  
Indium Tin Oxide ◽  
Nanoimprint Lithography ◽  
Large Scale ◽  
Electrode Materials ◽  
Ion Beam ◽  
Optoelectronic Devices ◽  
Device Fabrication ◽  
Two Dimensional ◽  
Ion Beam Etching

The application of nanopatterned electrode materials is a promising method to improve the performance of thin-film optoelectronic devices such as organic light-emitting diodes (OLEDs) and organic photovoltaics. Light coupling to active layers is enhanced by employing nanopatterns specifically tailored to the device structure. A range of different nanopatterns is typically evaluated during the development process. Fabrication of each of these nanopatterns using electron-beam lithography is time- and cost-intensive, particularly for larger-scale devices, due to the serial nature of electron beam writing. Here, we present a method to generate nanopatterns of varying depth with different nanostructure designs from a single one-dimensional grating template structure with fixed grating depth. We employ multiple subsequent steps of UV nanoimprint lithography, curing, and ion beam etching to fabricate greyscale two-dimensional nanopatterns. In this work, we present variable greyscale nanopatterning of the widely used electrode material indium tin oxide. We demonstrate the fabrication of periodic pillar-like nanostructures with different period lengths and heights in the two grating directions. The patterned films can be used either for immediate device fabrication or pattern reproduction by conventional nanoimprint lithography. Pattern reproduction is particularly interesting for the large-scale, cost-efficient fabrication of flexible optoelectronic devices.

Towards large-scale electrochemical energy storage in the marine environment with a highly-extensible “paper-like” seawater supercapacitor device

2021 ◽  
Vol 9 (1) ◽  
pp. 622-631
Author(s):  
Situo Cheng ◽  
Zhe Dai ◽  
Jiecai Fu ◽  
Peng Cui ◽  
Kun Wei ◽  
...  
Keyword(s):  
Energy Storage ◽  
Marine Environment ◽  
High Performance ◽  
Large Scale ◽  
Electrochemical Energy Storage ◽  
Architecture Design ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Promising Strategy ◽  
Electrochemical Energy

The all-in-one architecture design offers a promising strategy for future high-performance energy storage devices in the marine environment.

Seeded Growth of Single-Crystal Two-Dimensional Covalent Organic Frameworks

2017 ◽  
Author(s):  
Austin M. Evans ◽  
Lucas R. Parent ◽  
Nathan C. Flanders ◽  
Ryan P. Bisbey ◽  
Edon Vitaku ◽  
...  
Keyword(s):  
Molecular Transport ◽  
Controlled Synthesis ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Seeded Growth ◽  
Covalent Bonds ◽  
Crystalline Materials ◽  
Step Procedure ◽  
Structures And Properties ◽  
2D Polymer

<div> <div> <div> <p>Polymerizing monomers into periodic two-dimensional (2D) networks provides structurally precise, atomically thin macromolecular sheets linked by robust, covalent bonds. These materials exhibit desirable mechanical, optoelectrotronic, and molecular transport properties derived from their designed structure and permanent porosity. 2D covalent organic frameworks (COFs) offer broad monomer scope, but are generally isolated as polycrystalline, insoluble powders with limited processability. Here we overcome this limitation by controlling 2D COF formation using a two- step procedure. In the first step, 2D COF nanoparticle seeds are prepared with approximate diameters of 30 nm. Next, monomers are slowly added to suppress new nucleation while promoting epitaxial growth on the existing seeds to sizes of several microns. The resulting COF nanoparticles are of exceptional and unprecedented quality, isolated as single crystalline materials with micron-scale domain sizes. These findings advance the controlled synthesis of 2D layered COFs and will enable a broad exploration of synthetic 2D polymer structures and properties. </p> </div> </div> </div>

Seeded Growth of Single-Crystal Two-Dimensional Covalent Organic Frameworks

2017 ◽  
Author(s):  
Austin M. Evans ◽  
Lucas R. Parent ◽  
Nathan C. Flanders ◽  
Ryan P. Bisbey ◽  
Edon Vitaku ◽  
...  
Keyword(s):  
Molecular Transport ◽  
Controlled Synthesis ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Seeded Growth ◽  
Covalent Bonds ◽  
Crystalline Materials ◽  
Step Procedure ◽  
Structures And Properties ◽  
2D Polymer

<div> <div> <div> <p>Polymerizing monomers into periodic two-dimensional (2D) networks provides structurally precise, atomically thin macromolecular sheets linked by robust, covalent bonds. These materials exhibit desirable mechanical, optoelectrotronic, and molecular transport properties derived from their designed structure and permanent porosity. 2D covalent organic frameworks (COFs) offer broad monomer scope, but are generally isolated as polycrystalline, insoluble powders with limited processability. Here we overcome this limitation by controlling 2D COF formation using a two- step procedure. In the first step, 2D COF nanoparticle seeds are prepared with approximate diameters of 30 nm. Next, monomers are slowly added to suppress new nucleation while promoting epitaxial growth on the existing seeds to sizes of several microns. The resulting COF nanoparticles are of exceptional and unprecedented quality, isolated as single crystalline materials with micron-scale domain sizes. These findings advance the controlled synthesis of 2D layered COFs and will enable a broad exploration of synthetic 2D polymer structures and properties. </p> </div> </div> </div>

Pathway Complexity in the Stacking of Imine-linked Macrocycles Related to Two-Dimensional Covalent Organic Frameworks

2019 ◽  
Author(s):  
Shiwei Wang ◽  
Anton Chavez ◽  
Simil Thomas ◽  
Hong Li ◽  
Nathan C. Flanders ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Structural Similarity ◽  
Discrete Models ◽  
Side Chains ◽  
Two Dimensional ◽  
Assembly Process ◽  
Covalent Organic Frameworks ◽  
Electron Systems ◽  
Monomer Structure ◽  
Kinetic Traps

This work reports on the assembly of imine-linked macrocycles that serve as models of two-dimensional covalent organic frameworks (2D COFs). Interlayer interactions play an important role in the formation of 2D COFs, yet the effect of monomer structure on COF formation, crystallinity, and susceptibility to exfoliation are not well understood. For example, monomers with both electron-rich and electron-poor π-electron systems have been proposed to strengthen interlayer inter-actions and improve crystallinity. Here we probe these effects by studying the stacking behavior of imine-linked macrocycles that represent discrete models of 2D COFs. <div><br></div><div>Specifically, macrocycles based on terephthaldehyde (PDA) or 2,5-dimethoxyterephthaldehyde (DMPDA) stack upon cooling molecularly dissolved solutions. Both macrocycles assemble cooperatively with similar ΔHe values of -97 kJ/mol and -101 kJ/mol, respectively, although the DMPDA macrocycle assembly process showed a more straightforward temperature dependence. Circular dichroism spectroscopy performed on macrocycles bearing chiral side chains revealed a helix reversion process for the PDA macrocycles that was not observed for the DMPDA macrocycles. <br></div><div><br></div><div>Given the structural similarity of these monomers, these findings demonstrate that the stacking processes associated with nanotubes derived from these macrocycles, as well as for the corresponding COFs, are complex and susceptible to kinetic traps, casting doubt on the relevance of thermodynamic arguments for improving materials quality. <br></div>

Sign in / Sign up

Export Citation Format

Share Document