Triptycene based hole transport materials for dye sensitized solar cells

Researchers from China have synthesized three novel hole-conducting molecules which may give rise to significant economic advantages for the production of dye sentisized solar cells. Web writer Kevin writes more…

Dye sensitized solar cells (DSSCs) are photovoltaic devices which use a sensitizer in combination with a photosensitive material and a wide band gap semiconductor to produce an electric current. Thin-film DSSCs can offer packaging and application opportunites, have potential as functional coatings, and exhibit high power conversion efficiencies (PCE) of up to 12-13%.

Current state-of-the-art dye sensitized solar cells are usually solid phase systems, removing any issues surrounding leakage of components or the corrosive nature of some electrolytes. In such configurations a constituent known as a hole transport material (HTM) is now commonly used instead of a liquid electrolyte.

In this Chemical Science Edge article, authors from the Energy Research Institute, Nanyang, and the Nanyang Technological University, Singapore, give details of a group of triptycene based molecules which, they claim, perform on a comparable level with the current best in class HTM, (spiro-OMeTAD). The materials described were prepared from a starting tri-iodotryptycene material which was derivatised using a variety of transformations including Stille and Suzuki coupling reactions. The materials contain diphenylamine moieties separated from the triptycene core by aromatic spacers, enabling charge transfer.

These materials were fabricated in a complex process into a typical DSSC, containing fluorine doped tin oxide, semiconducting titanium dioxide and lead iodide perovskite dye sensitizer material. Power conversion efficiencies are comparable to devices comprimising the best performing HTMs. For the T102 andT103 derivatives, PCEs were reported as 12.24 and 12.38%, comparable to devices fabricated with spiro-OMeTAD (12.78%). Without a HTM present the number falls to less than 5%.

This article presents details of promising HTM materials which may give rise to significant economic advantages for the production and commercialisation of solid state DSSCs, with current best in class performance levels.

Read this HOT Chemical Science Edge Article for free* today:

Novel hole transporting materials based on triptycene core for high efficiency mesoscopic perovskite solar cells

Anurag Krishna, Dharani Sabba, Hairong Li, Jun Yin, Pablo P. Boix, Cesare Soci, Subodh G. Mhaisalkar and  Andrew C. Grimsdale
DOI: 10.1039/C4SC00814F

About the webwriter

Kevin Murnaghan is a guest web-writer for Chemical Communications. He is currently a Research Chemist in the Adhesive Technologies Business Sector of Henkel AG & Co. KGaA, based in Düsseldorf, Germany. His research interests focus primarily on enabling chemistries and technologies for next generation adhesives and surface treatments. Any views expressed here are his personal ones and not those of Henkel AG & Co. KGaA.

*Access is free untill the 11.07.14 through a registered RSC account – click here to register

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Fighting cancer with artificial antigen-presenting cells

Researchers from the Netherlands discuss the development of artificial antigen-presenting cells

Antigen-presenting cells (ACPs) are key players in the immune systems fight against cancer. On detection of tumor tissues, these ACPs pick up antigenic fragments of the tumor cell, migrate to the lymphoid organs and present the antigen to T-cells which play a central role in cell mediated immunity. Therefore, artificial ACPs (aAPCs) are often used in the development of immune-mediated anti-cancer therapies as they show great potential to mimic antigen-presentation, promoting T-cell activation.

Carl Figdor, a world-class immunologist, and colleagues from Radbound University discuss the current status of aAPC development in a Chemical Science Perspective. This review is partly focused on the developments in nanoscience which might improve future designs for immune-mediated anti-cancer therapies.

As a synthetic mimic, aAPCs must encompass the three signals that natural APCs use to encourage T-cell activation. This perspective discusses how these signals have been incorporated into aAPC designs, but also how physical properties such a size and shape are essential for targeting the aAPCs to T-cell rich areas in vivo.

Artificial antigen-presenting cells have the potential to develop into a widespread and powerful therapeutic tool. To download the full perspective, click on the link below – access is free for a limited time only!

Joep van der Weijden, Leonie Paulis, Martijn Verdoes, Jan C M van Hest and Carl Figdor
DOI: 10.1039/C4SC01112K
Looking for the best articles at the chemistry-biology interface. Check out our Chemical Biology Themed Collection showcasing some of the great research papers and reviews published in Chemical Science, in the areas of chemical biology and bioinorganic chemistry.
*Access is free through a registered RSC account – click here to register
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

A Faraday Discussion – Nanoparticle Synthesis and Assembly

Abstract submission is now open – submit your oral abstract by 21 July 2014

How does the nanoparticle-nanoparticle potential govern nanoparticle formation or assembly? Can one make more robust nanoparticle superlattice structures, which can be moulded, milled and machined into desired shapes? How does the assembly process vary with nanoparticle shape?

These questions cannot be answered in isolation – join the Nanoparticle Synthesis and Assembly, a Faraday Discussion which will be held on 20-22 April 2015 in Chicago, USA.

Abstract submission is now open, so take advantage of this excellent opportunity to showcase your latest research alongside leading scientists from across the globe. Don’t leave it too late – the deadline for oral abstracts is 21 July 2014.

Themes will include:

  • Nanoparticle synthesis – physical chemistry of nanoparticle shape and ligand control
  • Theoretical insights into nanoparticle synthesis and nanoparticle assembly
  • Nanoparticle self-assembly
  • Nanoparticle directed assembly

For more information and to see details of the speakers, visit the event website.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

The Importance of Biometal Distribution in Neurodegenerative Disorders

Iain Larmour is a guest web writer for ChemSci. He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies. He currently works in science management. In his spare time he enjoys reading, photography, art and inventing.

Anthony White from the Department of Pathology, University of Melbourne and team have investigated the use of X-ray Fluorescence Microscopy to investigate subcellular biometal homeostasis in a mouse model of the childhood neurodegenerative disorder – Batten disease. This is a particularly nasty disease that causes progressive blindness and motor impairment leading to premature death. The team have previously highlighted the redistribution of brain zinc in diseased samples using subcellular fractionation techniques. However, the lack of a rapid, specific and sensitive technique to provide quantitative subcellular information in situ on biometal distributions is severely limiting the understanding of the effect that the changes in biometals distributions can have in neurodegenerative diseases.

Consider the next time you go food shopping. What if you arrived at the supermarket and all the shelves were empty. A shop assistant reassures you that there is plenty of stock, hundreds of thousands of items indeed, but it all just happens to be sitting in their central depot instead of the supermarket. This does not help you to make dinner that night. This scenario is an example of how important the distribution of items can be.

When it comes to neurodegenerative disorders the location of biometals, just like the location of the groceries in the above case, provides much more useful information than the total amount of biometal present. The amount of biometal may not change between normal and diseased cells, but the distribution does. Biometals are important cofactors to a large number of enzymes and are also recognised as second messengers in neuronal signalling

Intracellular zinc and calcium distributions mapped by x-ray fluorescence microscopy.

In their Chemical Science paper the team have utilised the advances in data collection speed of X-ray fluorescence detectors to map the zinc and calcium distributions in a statistically relevant number of cells. Despite a lack of global changes in biometal levels this approach revealed the perturbed trafficking of zinc and the significantly altered subcellular calcium distributions. The restorative properties of a therapeutic zinc-complex were also shown using this technique.

Techniques and methodology reported in the Chemical Science paper can be applied to other neurodegenerative diseases and importantly can provide insights to the mechanism of action of novel therapeutics at the single cell level.

Read the Chem. Sci. paper in full today for free* and see if this technique could be applied to a disease you are studying!

X-ray fluorescence imaging reveals subcellular biometal disturbances in a childhood neurodegenerative disorder
A. Grubman, S.A. James, J. James, C. Duncan, I. Volitakis, J.L. Hickey, P.J. Crouch, P.S. Donnelly, K.M. Kanninen, J.R. Liddell, S.L. Cotman, M.D. de Jonge and A.R. White*
DOI: 10.1039/C4SC00316K


*Access is free until 20.06.14 through a registered RSC account – click here to register

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Photooxidation system that’s membrane-bound for success

Polly Wilson writes about a hot Chemical Science article for Chemistry World

Photosensitiser–water oxidation catalysts in heterogeneous (top), membrane-bound (middle) and homogeneous (bottom) systems

For the first time, a water oxidation catalyst and photosensitiser have been co-embedded into a membrane to make an artificial water photooxidation system. The arrangement can generate oxygen from water at far lower catalyst concentrations than ever before.

Chemical systems to turn solar energy into fuel are of paramount importance in the quest for sustainable green energy. Mimicking natural photosynthesis, the aim is to achieve sunlight-driven conversion of water and carbon dioxide into carbohydrates and oxygen. One branch of the process involves photocatalytic water splitting, comprising oxidative and reductive half reactions. The more complex photoxidation step involves a four-electron transfer reaction and very reactive oxygen intermediates. In nature, this extremely endothermic reaction is performed by Photosystem II (PSII), using membrane bound chromophores and catalytic units.


Read the full article in Chemistry World»

Read the original journal article in Chemical Science – it’s free to download until 30th June:
Photocatalytic water oxidation at soft interfaces
Malte Hansen, Fei Li, Licheng Sun and Burkhard König
Chem. Sci., 2014, Advance Article
DOI: 10.1039/C4SC01018C, Edge Article

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Immunocamouflage lets donor blood cells go undetected

Kirsty Muirhead writes about a hot Chemical Science article for Chemistry World

Chinese scientists are developing a new approach to create “universal” blood: red blood cells (RBCs) that can be transfused into any patient, regardless of the patient or recipient blood group.

Blood groups are characterised by the presence (or absence) of various proteins known as antigens on the surface of RBCs, the most well-known of which form the ABO system and the Rhesus D (RhD) system. One consequence of the existence of these groups is that blood mismatching can occur when an incompatible blood group is used for transfusion. The recipient’s antibodies recognise the antigens on the donor RBCs as being foreign and attack the cells – with potentially fatal results.

Antigenic epitopes on RBCs are sheltered by polydopamine


Read the full article in Chemistry World»

Read the original journal article in Chemical Science – it’s free to access until 1st July:
Antigenic-sheltering universal red blood cells by polydopamine-based cell superficial-engineering
Ben Wang, Guangchuan Wang, Binjie Zhao, Jiajun Chen, Xueyun Zhang and Ruikang Tang  
Chem. Sci., 2014, Accepted Manuscript, DOI: 10.1039/C4SC01120A, Edge Article

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Challenges in Inorganic and Materials Chemistry (ISACS13) – register before 2 June

Challenges in Inorganic and Materials Chemistry - ISACS13
Don’t miss your chance to attend Challenges in Inorganic and Materials Chemistry (ISACS13)

Final registration deadline – Monday 2 June Register now

Register to join Guy Bertrand, Susumu Kitagawa and Douglas Stephan and a host of impressive speakers at Challenges in Inorganic and Materials Chemistry (ISACS13).

Spaces are filling up fast so guarantee your place now.

We look forward to welcoming you to Dublin this July.

Professor Thorri Gunnlaugsson Dr Robert D. Eagling
Conference Chair Editor, Chemical Science
P.S. Join us for the 5th Joint CSJ RSC Symposium on Supramolecular Chemistry which is being held on 1st July in Dublin, just before the start of ISACS13. It’s free to attend and registration is open now.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

First total synthesis of propolisbenzofuran B

Kate Montgomery is currently doing a PhD in drug delivery using polymer based nanoparticles, her project is a collaboration between Imperial College London and CSIRO in Melbourne. When she is not making extremely sticky polymers in the lab, Kate enjoys reading, running (very slowly) and deep sea diving.

propolisbenzofuran BRegan Thomson’s group from Northwestern University, Illinois, present the first total synthesis of propolisbenzofuran B. The synthesis has been completed in 17 steps, starting from the phenolic aldehyde, vanillin.

In the natural world propolis is a resin made by bees and used in their hives to preserve a sterile environment. It encases waste and carcasses to prevent the decomposition of proteins and therefore decay.

The beneficial health effects of honeybee products have been hypothesised since ancient Roman times. More recently it has been determined that propolis has many biological and pharmacological properties including antibacterial, antibiotic, anti-oxidant, anti-fungal, anti-cancer and anti-inflammatory activities.

Propolisbenzofuran B is a natural product found in Brazilian propolis, first isolated in 2000 by Banskota and co-workers. Initial biological testing determined that the compound had a cytotoxic effect on murine colon 26-L5 carcinoma and human HT-1080 fibrosarcoma cells.

It was not only the promising range of biological activity which drew the authors’ attention to this particular compound; propolisbenzofuran B has a unique core with an unusual ring-system. The development of an efficient synthesis for this core opens the door to further biological evaluation and possible modifications to the compound.

Highlights of the synthesis include a silicon-tether controlled oxidative ketone-ketone cross-coupling as well as a novel and efficient benzofuran cascade. The cascade was discovered to be induced rapidly with the addition of trimethylsilyl triflate to the 1,4-diketone precursor. The authors believe this methodology will be useful in the synthesis of other complex molecules containing benzofuran groups.

To download the full article for free* click the link below:

Total synthesis of propolisbenzofuran B
Brian T. Jones, Christopher T. Avetta and Regan J. Thomson
DOI: 10.1039/c4sc00356j

*Access is free untill 13.06.14 through a registered RSC account – click here to register

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Beyond Zeros and Ones – Molecular Data Processing

Iain Larmour is a guest web writer for ChemSci. He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies. He currently works in science management. In his spare time he enjoys reading, photography, art and inventing.

We live in the technological age, surrounded by gadgets and gizmos with computer chips inside. They make our lives easier (mostly) and their speed just seems to keep increasing. But the computations only use binary code, zeros and ones and the speed at which they can be carried out will ultimately be limited by the size that the silicon circuits can be reduced to. What if computations could be done on a single molecule, which has been shown before, but also with the use of more than just two numbers? How about adding two and three to the available list of numbers? This is what Skrollan Stockinger and Oliver Trapp from the Ruprecht-Karls-Universitat Heidelberg detail in their recent Chemical Science paper.

They report a ternary/quaternary logic system based on a mixture of benzonitrile oxide with iron(III) ions and zinc ions which changes colour depending on the inputs. Using photographic recording and analysis of the Red/Green/Blue (RGB) values they can read out four different states: colourless, yellow, deep purple and a solution with precipitate present. This creates a system that gives the user a higher information processing density.

Two molecular logic systems with two independent input factors resulting in a continuous system and a system with a quaternary basis.

Does information processing really have to be restricted to zeros and ones? Using sodium thiocyanate ions rather than zinc ions the authors have created a continuous system. The sodium thiocynate creates a red complex and analysis of the RGB channels allow a range of concentrations to be detected which could be split up into any number of states for computation, rapidly increasing the information processing density. Therefore this continuous system could extend multi-valued logic beyond the ternary and quaternary systems described in the literature and the current paper.

Both systems show very good long-term stability and could find uses as a high potential storage medium with high data processing ability.

To find out the details of this work read the Chem. Sci. paper in full for free* today:

A Continuous and Multi Valued System as Molecular Answer for Data Processing and Data Storage

Skrollan Stockinger and Oliver Trapp

DOI: 10.1039/C3SC53576B

*Access is free untill 12.06.14 through a registered RSC account – click here to register

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Supramolecular velcro unzipped by a voltage

Cally Haynes writes about a hot Chemical Science article for Chemistry World

Scientists in China have designed a velcro-like material held together by non-covalent interactions that can be unfastened by electrical means and refastened again under pressure.

The velcro is ‘stuck’ together by compressing a flexible, conductive poly(ionic liquid) membrane (PIL) functionalised with ferrocene (Fc) with a PIL functionalised with β-cyclodextrin (β-CD). The strong binding of the Fc groups within the β-CD cavities causes the layers to adhere together tightly. Oxidation of the Fc moieties to ferrocenium ions (Fc+) by chemical or electrochemical means causes the layers to come unstuck, as the charged Fc+ is not bound inside the hydrophobic β-CD cavity. A reducing potential and further pressing reassembles the material.

A hook-and-loop strategy fastens the layers together but these links can be unfastened by an electric current


Read the full article in Chemistry World»

Read the original journal article in Chemical Science – it’s free to download until 19th June:
Flexible and Voltage-Switchable Polymer Velcro Constructed by Host−Guest Recognition Between Poly(ionic liquid) Strips
Jiangna Guo, Chao Yuan, Mingyu Guo, Lei Wang and Feng Yan  
Chem. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C4SC00864B, Edge Article

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)