Archive for the ‘Hot Article’ Category

Materials Horizons author profile: Jean-Luc Bredas

Materials Horizons Advisory Board member, Jean-Luc Brédas, is the author of the journal’s first Focus article, Mind the gap! Focus articles are educational pieces, intended to explain or clarify topics relevant to the understanding of materials science. In his article, Professor Brédas seeks to clear up the confusion surrounding the many types of energy gap relevant to organic materials, and calls for a more rigorous use of the appropriate terminology. Here we find out more about the author, and why he chose to write this article for Materials Horizons.

Jean-Luc Brédas is Regents’ Professor of Chemistry and Biochemistry at Georgia Institute of Technology. He began his research career at the Université de Namur, Belgium, where he completed a Ph.D. in Theoretical Chemistry.  Since then, he has held positions at Université de Mons, Belgium, the University of Arizona, USA, and King Abdulaziz University in Saudi Arabia. He is the author or co-author of over 950 scientific papers and has presented over 500 invited talks at scientific meetings and seminars.

Professor Brédas has been awarded numerous prizes in recognition of his work, including the Triennal Prize of the Royal Society of Chemistry, Belgium, (1991), the Francqui Prize (1997), the Descartes Prize of the European Commission (2003) and the Georgia Institute of Technology Outstanding Faculty Research Author Award (2008). In 2013, he received the American Physical Society David Adler Lectureship Award in Materials Physics.  He has been a Fellow of the Royal Society of Chemistry since 2008.

The research activities of Professor Brédas’ group are focused on the computational characterization and design of novel organic materials of relevance for organic electronics and photonics.

What was the motivation to write your Materials Horizons Focus article?
There were two major reasons: The first is the original concept behind these Focus articles, which I believe is unique to Materials Horizons. The second is that many of my colleagues and myself were becoming increasingly frustrated by the lack of rigor surrounding the use of common terminologies in materials research articles, in particular with regard to energy gaps and energy levels in electro-active organic materials. Hence, when Seth Marder came to me with a proposition to write such a Focus article, he met no resistance!

At which upcoming conferences may our readers meet you?
In the spring, I’ll participate in SPIE Photonics West in San Francisco, the ACS National Meeting in Dallas, and the MRS Spring Meeting (again in San Francisco).

How do you spend your spare time?
Soccer, or should say much more appropriately football, is my main passion besides science. I still try to play as much as I can especially with my students. Also, I very much enjoy tending to the four fish tanks I have at home, with fish (cichlids) mainly from the Central Africa Lakes: Tanganyika and Malawi.

Which profession would you choose if you were not a scientist?
This is a tough question because I cannot picture myself doing something else really. The fulfillment that scientific research, teaching students, and making friends all over the world bring, would be in my mind very difficult to match. But to answer the question, maybe I’d like to be in the sports business, for instance as a commentator.

Mind the gap!

Jean-Luc Brédas
Mater. Horiz., 2014, 1, 17-19
DOI: 10.1039/C3MH00098B

‘The energy gap is a critical material parameter. Here, we illustrate the concepts behind the various flavors of energy gaps relevant for organic materials and call for a more consistent use of appropriate terminologies and procedures.’

 

 

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Materials Horizons author profile: Professor Gordon Wallace

You may have seen Gordon Wallace’s recent Materials Horizons communication on liquid crystalline dispersions of graphene oxide. (If not, take a look here; it’s free to access!) Here, we profile the author, and ask him about his experience with Materials Horizons.

Professor Gordon Wallace is currently the Executive Research Director at the ARC Centre of Excellence for Electromaterials Science and Director of the Intelligent Polymer Research Institute. He previously held an ARC Federation Fellowship and currently holds an ARC Laureate Fellowship. Professor Wallace’s research interests include organic conductors, nanomaterials and electrochemical probe methods of analysis, and the use of these in the development of Intelligent Polymer Systems. A current focus involves the use of these tools and materials in developing bio-communications from the molecular to skeletal domains in order to improve human performance via medical Bionics.

With more than 700 refereed publications, Professor Wallace has attracted some 17,000 citations and has a h-index of 61. He has supervised 77 PhD students to completion at the Intelligent Polymer Research Institute and currently co-supervisors 30 PhD students.

Professor Wallace is an elected Fellow at the Australian Academy of Science, the Australian Academy of Technological Sciences and Engineering, the Institute of Physics (UK) and the Royal Australian Chemical Institute. In addition to being named NSW Scientist of the Year in the chemistry category in 2008, Professor Wallace was also appointed to the Korean World Class University System, and received the Royal Australian Chemical Institute HG Smith Prize.

Why did you choose Materials Horizons to publish your exciting work?
I like the approach that combines education and digestible insights with the forefront of research. More and more I realise the critical need to communicate advances in knowledge emanating from the research laboratory to a broad cross section of our communities as effectively and efficiently as possible.

How did you find the Materials Horizons publication process?
The process was effective and efficient.

What topics would you like to see covered in future issues of Materials Horizons?
I think some coverage of advances in BioAFM would be most timely.

 

Formation and processability of liquid crystalline dispersions of graphene oxide
Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Joselito M. Razal, Simon E. Moulton and Gordon G. Wallace
Mater. Horiz., 2014, Advance Article DOI: 10.1039/C3MH00050H

Manipulation of graphene oxide sheets to form liquid crystalline dispersions enabling fabrication of multifunctional 3D-structures.

 

 

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Materials Horizons – new advanced articles have been published!

Molecular Crystalline Materials with Tunable Luminescent Properties: From Polymorphs To Multi-component Solids
Dongpeng Yan and David G. Evans

Tuning and controlling the luminescent properties of molecular materials by changing the orientation and arrangement of the fluorophores within a solid has played an important role in realizing multi-color emission. The formation of polymorphs and multi-component molecular solids have attracted considerable interest as new ways of achieving controllable luminescence and other photophysical properties for application in the next generation of photofunctional materials. In this article, recent advances in the synthesis of fluorescent polymorphs and multi-component materials and potential photo-related applications of the resulting materials are described. We first review the methods of preparation of polymorphs with tunable static luminescence, and the switching of the dynamic luminescence between polymorphs for potential sensor applications is also introduced. Attention is then focused on the supramolecular design (making use of hydrogen bonding and halogen bonding interactions) and methods of fabrication of multi-component molecular solids, and their color-tunable fluorescence and phosphorescence together with their stimuli-responsive properties for use as sensors. The use of density functional theory to study intramolecular and intermolecular energy transfer as well as the electronic structures of multi-component molecular solids is also outlined. Finally, we briefly discuss perspectives for the further development of these luminescent molecular solid-state materials.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00023k, Advance Article

A Shape-memory scaffold for macroscale assembly of functional nanoscale building blocks
Huai-Ling Gao, Yang Lu, Li-Bo Mao, Duo An, Liang Xu, Jun-Tong Gu, Fei Long and Shu-Hong Yu

A shape-memory chitosan scaffold (CSS) fabricated by an ice-templated method can be used as a versatile host matrix for self-assembly of a wide range of functional nanoscale building blocks, and thus it can produce a family of functional three-dimensional (3D) macroscale assemblies, which show promising practical application potential in various fields.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00040k, Advance Article

 
 
 
 
 
 
 

Large-area arrays of three-dimensional plasmonic subwavelength-sized structures from azopolymer surface-relief gratings

Robert J. Moerland, Jenni E. Koskela, Aleksandr Kravchenko, Mikael Simberg, Stefan van der Vegte, Matti Kaivola, Arri Priimagi and Robin H. A. Ras

The field of plasmonics allows for confinement and control of light on the nanoscale. Due to potentially strong resonant interactions that light can have with metal nanoscale structures, metals are a good candidate to tailor interactions with light, e.g., periodic arrays of subwavelength metal structures can support extremely narrow resonances and show enhanced transmission. The field of plasmonics has evolved from using simple geometries to the desire to create complex nanostructures for improved control. The availability of fabrication techniques that provide for complex structures, however, is paired with the seemingly inevitable increase in complexity of fabrication techniques themselves. We present a facile and scalable method for the fabrication of periodic arrays of unique three-dimensional subwavelength-sized structures such as tapered holes and pyramidically shaped subwavelength-sized particles. The procedure consists of holographic inscription of a two-dimensional surface-relief grating in an azobenzene-containing polymer film, evaporative gold deposition and broad-beam ion milling of the relief structure. The method allows the fabrication of highly uniform arrays with tunable lattice parameters and dimensions over large sample areas. The optical response of the fabricated structures is determined experimentally and through simulation, which confirm the unique plasmonic response of the structures. While the proposed fabrication method has clear benefits for plasmonics, it could easily be applied also in other fields, for example by using other coating materials.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00008g, Advance Article

Magnesium-air battery: from principle to application

Tianran Zhang, Zhanliang Tao and Jun Chen

Metal–air batteries are important power sources for electronics and vehicles because of their remarkable high theoretical energy density and low cost. In this paper, we introduce the fundamental principles and applications of Mg–air batteries. Recent progress in Mg or Mg alloys as anode materials and typical classes of air cathode catalysts for Mg–air batteries are reviewed. In the meantime, different compositions of the electrolyte are also compared. The design of electrode materials both for anodes and cathodes of Mg–air batteries is discussed for further performance improvement. It is noted that in the development of rechargeable Mg–air batteries, bi-functional catalysts with reversible oxygen reduction and evolution reactions are facing challenges and it is worthwhile devoting much effort to this.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00059a, Advance Article
 
  
 

Formation and Processability of Liquid Crystalline Dispersions of Graphene Oxide

Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Joselito M. Razal, Simon E. Moulton and Gordon G. Wallace

Rational control over the formation and processability, and consequently final properties of graphene oxide liquid crystalline dispersions has been a long-standing goal in the development of bottom-up device fabrication processes. Here we report, the principal conditions through which such levels of control can be exercised to fine-tune dispersion properties for further processing.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00050h, Advance Article

 
 
   
 
 
 
 
 
 
 

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The first advance articles for Materials Horizons have been published!

Chemotaxis of Catalytic Silica-Manganese Oxide “Matchstick” Particles
Adam R. Morgan, Alan B. Dawson, Holly S. Mckenzie, Thomas S. Skelhon, Richard Beanland, Henry P. W. Franks and Stefan A. F. Bon

Particles that can undergo directed self-propulsion are desirable for colloidal cargo delivery and self-assembly. This paper describes the synthesis of silica–manganese oxide “matchstick” colloids that undergo catalytic self-propulsion by consumption of hydrogen peroxide. Chemotaxis is observed when particles are placed in a fuel gradient.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00003f, Advance Article

 
 

Highly dispersible polypyrrole nanospheres for advanced nanocomposite ultrafiltration membranes
Yaozu Liao, Thomas P. Farrell, Gregory R. Guillen, Minghua Li, James A. T. Temple, Xin-Gui Li, Eric M. V. Hoek and Richard B. Kaner

In this paper, highly dispersible polypyrrole nanospheres were synthesized and used to produce polysulfone nanocomposite ultrafiltration membranes by a non-solvent induced phase separation process. The composite networks formed between polypyrrole nanospheres and polysulfone nanocomposites lead to higher porosity, hydrophilicity, surface charge, thermal stability, and water permeability, but slightly lower protein rejection.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00049d, Advance Article

  
 
 
 
 


 

Production of heavily n- and p-doped CVD graphene with solution- processed redox-active metal-organic species
Sergio A. Paniagua, Jose Baltazar, Hossein Sojoudi, Swagat K. Mohapatra, Siyuan Zhang, Clifford L. Henderson, Samuel Graham, Stephen Barlow and Seth R. Marder

In this paper, CVD graphene has been n- and p-doped using redox-active, solution processed metal–organic complexes. Electrical measurements, photoemission spectroscopies, and Raman spectroscopy were used to characterise the doped films and give insights into the changes.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00035d, Advance Article

 
 
  
 

Vesicle budding from polymersomes templated by microfluidically prepared double emulsions
Julian Thiele, Venkatachalam Chokkalingam, Shaohua Ma, Daniela A. Wilson and Wilhelm T. S. Huck

Many approaches to mimic and understand the dynamics of vesicle budding lack precise control over vesicle membrane properties or require external stimuli to induce budding. This paper reports the use of copolymer loaded double-emulsion droplets to precisely control size, size distribution, composition and morphology of giant polymersomes. By tuning the copolymer concentration in the polymersome membrane, the authors show how they identify conditions under which vesicles spontaneously bud from the polymersome surface. These findings have important implications for the design of copolymer membranes and contribute to the understanding of polymersome formation from double emulsions.

Mater. Horiz., 2014, DOI: 10.1039/c3mh00043e, Advance Article

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