H. L. Parker – Journal of Materials Chemistry Blog

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A highly novel class of luminescent material

19 May 2015

Despite the wordy and jargon laden title this paper by Wang et al presents interesting work on a highly novel class of luminescent material.

It is generally understood that when chromophores aggregate their emission is quenched, an event know as aggregation-caused quenching (ACQ). The main problem with this ACQ occurring is that it limits the use of these luminescent molecules in applications such as bio-imaging and sensors where brightness is key.

In response to this many research groups have focused on developing materials that are the exact opposite of ACG’s and where aggregation of the chromophores will actually promote luminescence. This phenomenon is referred to as aggregation-induced emission (AIE).

This paper presents work about a novel type of AIE material that overcomes the shortfalls of ACG and some other previous AIE luminogens. A red-emissive barbituic acid-functionalized TPE derivative (TPE-HPh-Bar) was designed and synthesized, the resulting material exhibits both AIE and also twisted intramolecular charge transfer (TICT). By altering the method of synthesis the TPE-HPh-Bar is capable of self-assembling into nanospheres, -rods and -tubes. All of these exciting characteristics indicate that this novel material could be used in a wide range of applications from biological imaging to optoelectronic nano-devices in the future.

Twisted intramolecular charge transfer, aggregation-induced emission, supramolecular self-assembly and the optical waveguide of barbituic acid-functionalized tetraphenylethene
Erjing Wang, Jacky W. Y. Lam, Rongrong Hu, Chuang Zhang, Yong Sheng Zhao and Ben Zhong Tang
J. Mater. Chem. C, 2014, 2, 1801-1807. C3TC32161D

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Self-assembled growth of Sn@CNTs on vertically aligned graphene for binder-free high Li-storage and excellent stability

12 Nov 2014

The first thing I did after reading this article was google Li-ion batteries. I know the general stuff about them but I wanted to know more – typical scientist. They really are pretty fantastic, even lithium itself is rather special. I have never really thought about it before but lithium is the lightest of all the metals yet it has the greatest electrochemical potential and provides the largest energy density for weight. Although Li-ion does have a slightly lower energy density than lithium metal it makes a safer battery, especially where recharging is concerned. Sony were the first to commercialise the use of the Li-ion battery in 1991 and they are still the battery of choice especially for tech items such as mobile phones.

Self-assembled growth of Sn@CNTs on vertically aligned graphene for binder-free high Li-storage and excellent stability

Anyway enough of a history lesson. Despite being an incredily promising battery there are drawbacks to the use of Li-ion batteries. One of which is addressed in this work by Li et al is the lack of suitable electrodes with enhanced energy and power density, cycling stability, energy efficiency and cycling life. Metallic Sn has attracted significant attention as a promising anode material that over comes some of these issues. This paper reports for the first time a new stratergy to grow self-assembled tin carbon nanotubes on vertically aligned graphene. The work uses microwave plasma irradiation to produce the encapsulated Sn nanoparticles in the CNTs.

The resulting Sn anode is shown to give the best performance values of any other Sn anode to date. The authors write that they “expect the proposed route to be adopted by the rapidly growing energy storage research community” and with these results they might not be far off the mark.

Self-assembled growth of Sn@CNTs on vertically aligned graphene for binder-free high Li-storage and excellent stability
Na Li, Huawei Song, Hao Cui, Guowei Yang and Chengxin Wang
J. Mater. Chem. A, 2014, 2, 2526-2537. C3TA14217E

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: The role of material structure and mechanical properties in cell-matrix interactions

18 Jun 2014

When thinking about movement of the human body it is often thought about it in terms of muscles contracting and relaxing, joints bending and straightening, but I don’t think I have ever thought about movement on a cellular level.

During movement cells in our bodies are subject to mechanical force and as a result they are stretched, sheared and compressed. Many cells passively experience this force and some have even evolved to be particularly sensitive to it and act as sensors – such as the tiny hairs present inside the human ear.

However, some cells are a bit more active and can actually exert their own mechanical force on the environment around them. This interaction is used to achieve various physiological functions like the healing of tissue, fighting infection and growth and differentiation of cells. In order to carry out these functions the cells must be able to sense and understand the mechanical context of the world around them.

This review summarises the evolution of the area of science focused on understanding the mechanobiology of cells and tissues and how different properties of their surrounding environment can be analysed both scientifically and by the cell itself. It also goes further to discuss of different material properties effect the mechanosensing of cells. Whilst this is still a developing field this review gives a good overview of where our present understanding is at and what limitations there are to overcome in the future.

The role of material structure and mechanical propertie in cell-matrix interactions
Nicholas D. Evans and Eileen Gentleman
J. Mater. Chem. B, 2014, 2, 2345-2356. C3TB21604G

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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NIR Luminescent Nanomaterials for Biomedical Imaging

03 Jun 2014

Commonly in my household the phrase “you make a better door than you do a window” is often fired at whichever thoughtless member is blocking the latest episode of whatever intelligence diluting programme is being watched at the time. However, this same, seemingly mundane problem, of human solidity is also being suffered by scientists developing new techniques for biomedical imaging.

Luminescent labels have been widely used for biological applications, primarily bioimaging and assays. They offer advantages over tomographic imaging techniques (e.g. CT, PET and MRI) including fast feedback and high selectivity and resolution. Unfortunately, adsorption and scattering of the photos emitted by these labels caused by biological tissue and water inside the body create problems such as weak signals and limited depth of detection.

Luckily, there are some wavelengths of light that are not adsorbed by the body and fall into what is known as the “biological transparency window”. There are two ranges: NIR I 650 – 900 nm and NIR II 1000 – 1450 nm. Since the discovery of these NIR regions research has increased with the focus of developing nanomaterials that can be excited or emitted within these wavelengths. The main content of this review written by Wang and Zhang is an overview of these novel nanomaterials, divided into four main species: lanthanide based nanomaterials, carbon based nanomaterials, quantum dots and noble metal nanoparticles. Covering their fabrication and application and also their shortcomings and what challenges and opportunities there are in the future.

NIR Luminescent Nanomaterials for Biomedical Imaging
Rui Wang and Fan Zhang
J. Mater Chem. B, 2014, 2, 2422-2443. C3TB21447H

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: A simple, low-cost CVD route to thin films of BiFeO3 for efficient water photo-oxidation

19 May 2014

Hydrogen holds immeasurable promise in our search for alternative, sustainable, cleaner fuels. However, the simple, cheap production of hydrogen is still proving a problem. Water photolysis is a great way to achieve pure H₂ and as O₂ is the only side product it does not result in the harmful greenhouse gas emissions that arise from using hydrocarbons to produce H₂. Unfortunately, the generation of H₂ by water photolysis is challenging as the reaction that forms O₂ is much slower than the H₂ forming reaction. The use of an efficient photocatalyst can significantly improve the success of this process.

This paper by Moniz et al. details the development of just such a photocatalyst. In this work a bimetallic BiFeO₃ catalyst is prepared using a novel method of Aerosol Assisted Chemical Vapour Deposition (AA CVD). This is the first time that this method has been used to prepare a photocatalyst of this type. The team go on to test this photocatalyst for the electrolysis of water using both UV and solar irridation and encouragingly, activity is confirmed for the BiFeO₃ catalyst. Even more impressively the catalyst greatly outperforms both a commercially available photocatalyst (TiO₂ Activ^® glass) and another recently published photocatalyst (B-doped TiO₂ films).

The novel synthetic methodology presented in this paper enables large area thin film deposition and as a result has potential for high volume applications in the future.

A simple, low-cost CVD route to thin films of BiFeO₃ for efficient water photo-oxidation

Savio J. A. Moniz, Raul Quessada-Cabrera, Christopher S. Blackman, Junwang Tang, Paul Southern, Paul M. Weaver and Claire J. Carmalt,
J. Mater. Chem. A, 2014, 2, 2922-2927 C3TA14824F

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: A highly luminescent chameleon: fine-tuned emission trajectory and controllable energy transfer

16 May 2014

Luminescent materials are a part of our everyday life featuring in lighting, television screens, etc. The recent emergence of lanthanide-based metal-organic frameworks (Ln-MOFs) has illuminated the future development of new functional luminescent materials. Research into Ln-MOFs is still at its early stages but they have shown promise in the development of effective novel compounds.

This paper by Zhang et al. takes Ln-MOFs to the next level and presents the first example of mixed-lanthanide MOFs. The work combines Eu³⁺, Gd³⁺ and Tb³⁺ as co-doped ions on to one MOF framework. The co-doped Ln-MOF is capable of excitation-dependent mutual conversion between blue, white and yellow emission chromaticity…I am guessing this is where the rather whimsical title has come from.

This succinctly written communication gives a first look at the synthesis and testing of this exciting new Ln-MOF and gives an idea of where the research into Ln-MOFs might be heading in the future.

A highly luminescent chameleon: fine tuned emission trajectory and controllable energy transfer
Huabin Zhang, Xiaochen Shan, Zuju Ma, Liujiang Zhou. Mingjian Zhang, Ping Lin, Shengmin Hu, En Ma, Renfu Li and Shaowu Du
J. Mater Chem. C, 2014, 2, 1367-1371. C3TC31624F

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: Chemical modification of inorganic nanostructures for targeted and controlled drug delivery in cancer treatment

14 Apr 2014

The use of engineered nanostructures in biomedical applications and optimized therapy is revolutionising medicine and the way we treat disease. It probably doesn’t come as a surprise that cancer is one of the biggest driving forces responsible for development of therapeutic nanotechnologies. The potential for earlier detection and targeted treatment of tumours using nanotechnologies will act not only to reduce the number of cancer deaths but also reduce the side effects and increase the efficacy of treatments.

This review by Zhang et al. examines the recent advances in nanotechnology for targeted drug delivery and controlled drug release in cancer treatment. The focus of the introduction is on inorganic nanostructures, highlighting the advantages of these materials over bioorganic nanomaterials, namely the ease of synthesis, modification and the control of size, shape and surface functionalization can be carried out. All of which allow for the design of materials for specific tissue or cell type targeting, controlled drug delivery and in vivo diagnostic imaging.

The review also covers the mechanisms of systematic targeted drug delivery, stimuli-responsive drug release and biocompatibility of these inorganic nanostructures. Overall, this review gives a clear and varied look at the different technologies under development that I would recommend to many scientists, not just those working in this field.

Chemical modification of inorganic nanostructures for targeted and controlled drug delivery in cancer treatment
Lei Zhang, Yecheng Li and Jimmy C. Yu
J. Mater Chem. B, 2014, 2, 452-470. C3TB21196G

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Si nanotubes ALD coated with TiO2, TiN or AL2O3 as high performance lithium ion battery anodes

03 Mar 2014

The battery is one of the biggest obstacles that is limiting many energy related breakthroughs. From allowing the capture and storage of renewable energy that will accommodate the fluctuating needs of power usage, to the use of electric cars that are able to drive further without needing to be recharged. Many solutions are being sort, some of them seeming increasingly wacky, such as the use of rhubarb to make flow batteries being carried out by Harvard researchers.

Yet it is the much more traditional low-cost lithium-ion batteries that are the most popular. These batteries are already included in a range of commercially available electric cars and small electronic gadgets. The specific energy storage capacity and the charge/discharge rate of Li-ion batteries is critical for their use and increasing this life time remains a significant challenge for their further development.

One method for the improvement is to use silicon based hollow nanostructures as high energy density anodes in these batteries. Using Si as the anode material can considerably increase the energy storage capacity of the battery; however commercialisation remains limited due to the materials accelerated mechanical failure relative to conventional anode materials. This paper by Lotfabad et al, uses atomic layer desorption of TiO2, TiN and Al2O3 on to the inner, outer or both surfaces of hollow Si nanotubes in order to overcome this mechanical failure and enhance the cycling performance of the material. Their results show that by coating with TiO2 both inside and out of the nanotube the coulombic efficiency is as high as 99.9% (among the highest ever reported for this group of materials). In reality this could mean a battery lifetime of up to 1000 cycles. The results presented in this paper are extremely promising for the future of Li-ion batteries.

Si nanotubes ALD coated with TiO2, TiN or AL2O3 as high performance lithium ion battery anodes
Elmira Memarzadeh Lotfabad, Peter Kalisvaart, Alireza Kohandehghan, Kai Cui, Martin Kupsta, Behdokht Farbod and David Mitlin,
J. Mater. Chem. A, 2014, 2, 2504-2516. c3ta14302c

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: Versatile van der Waals epitaxy-like growth of crystal films using two-dimensional nanosheets as a seed layer: orientation tuning of SrTiO3 films along three important axes on glass substrates

07 Feb 2014

Thin films are a part of everyday life; if you looked in a mirror today you experienced the advantages of a thin film at work. Crystalline thin films can be made of a range of functional materials and are essential to achieve the desired functionality of various devices including micromachines (not the miniature racing cars but micro-electronic-mechanical systems or MEMS). Crystal films can offer characteristics such as ferroelectricity and piezoelectricity, however these properties are strongly dependent on crystal orientation, degree of orientation and film crystallinity.

Epitaxial growth has become a highly important method for growing crystalline films as it allows for tailoring of properties in order to control electronic, optical and magnetic qualities. Unfortunately as described in this paper by Shibata et al, one of the basic requirements for attaining a good epitaxy is a close structural matching between a substrate and a growing crystal epilayer. This restriction causes a major obstacle for its wide application. In order to overcome this problem these researchers, led by Takayoshi Sasaki, have used 2D inorganic nanosheets of either Ca₂Nb₃O₁₀^–, Ti_0.87O₂^0.52- or MoO₂^δ- as highly organised layers depositied onto amorphous glass. These different surfaces allow for the deposition of SrTiO₃ on to the glass with precise and selective control of crystallographic orientation.

This novel technique has already grabbed press attention because of its cost-effective and universal nature that comes from the possibility to use conventional substrates such as glass and plastic that wasn’t possible before. Whilst some development is still required this technique is already being seen as a huge leap forward in the growth of crystal films that will bring significant technological innovation in the future.

Versatile van der Waals epitaxy-like growth of crystal films using two-dimensional nanosheets as a seed layer: orientation tuning of SrTiO₃ films along three important axes on glass substrates

Tatsuo Shibata, Hikaru Takano, Yasuo Ebina, Dae Sung Kim, Tadashi C. Ozawa, Kosho Akatsuka, Tsuyoshi Ohnishi, Kazunori Takada, Toshihiro Kogure and Takayoshi Sasaki

J. Mater. Chem. C, 2014, 2, 441-449 C3TC31787K

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Hot Article: Micro- and nano-motors for biomedical applications

06 Feb 2014

Abdelmohsen et al write in the first line of this review “biological motors are one of the most remarkable products of evolution” and I couldn’t agree more. Nanoscale biomotors are common in nature and these tiny machines have inspired scientists to copy nature and attempt to develop man-made micro- and nano-motors themselves. Incredibly, machines that are as small as one 60,000th of a human hair have already been made.

Micro-machines show remarkable promise for use in a wide range of biomedical applications; including drug delivery, sensing and isolation, nanosurgery and imaging that would enable targeted or non-invasive medicine to be carried out. Although as this review points out there is still a considerable amount of work to take micro- and nano-machines for in vivo applications from concept into reality.

This paper covers topics including micro-motor design, potential fuel and fuel free machines and new developments for their use in biomedical applications and gives an interesting and balanced insight into the work of micro-machines highlighting the opportunities and challenges currently facing this field.

Micro- and nano-motors for biomedical applications

Loai K. E. A. Abdelmohsen, Fei Peng, Yingfeng Tu and Daniela A. Wilson,

J. Mater. Chem. B, 2014. C3TB21451F

H. L. Parker is a guest web writer for the Journal of Materials Chemistry blog. She currently works at the Green Chemistry Centre of Excellence, the University of York.

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Journal of Materials Chemistry Blog

Author Archive

A highly novel class of luminescent material

Self-assembled growth of Sn@CNTs on vertically aligned graphene for binder-free high Li-storage and excellent stability

Hot Article: The role of material structure and mechanical properties in cell-matrix interactions

NIR Luminescent Nanomaterials for Biomedical Imaging

Hot Article: A simple, low-cost CVD route to thin films of BiFeO3 for efficient water photo-oxidation

Hot Article: A highly luminescent chameleon: fine-tuned emission trajectory and controllable energy transfer

Hot Article: Chemical modification of inorganic nanostructures for targeted and controlled drug delivery in cancer treatment

Si nanotubes ALD coated with TiO2, TiN or AL2O3 as high performance lithium ion battery anodes

Hot Article: Versatile van der Waals epitaxy-like growth of crystal films using two-dimensional nanosheets as a seed layer: orientation tuning of SrTiO3 films along three important axes on glass substrates

Hot Article: Micro- and nano-motors for biomedical applications

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