Journal of Materials Chemistry Blog

David Schuster, Jackson Megiatto and Robert Spencer have developed a powerful and versatile new methodology for the preparation of nanoscale photoactive interlocked structures with appended [60]fullerene groups.  The group from New York University used a straightforward one-pot procedure based on Cu(I)-template synthesis and “click” chemistry.

The use of organic materials for absorption of solar energy and conversion into high energy charge-separated carriers has been reproduced in the laboratory by carefully designed artificial arrays containing electron donor and acceptor (D–A) subunits. The synthetic achievements described in this paper open the door to the preparation of nanoscale D–A materials with rotaxane and catenane topologies not accessible previously. Introduction of C60 groups in interlocked structures generates the driving force allowing electron transfer reactions to occur over very long distances.

Interested in knowing more?  This article will be free until the 8th November, read it here.

Optimizing reaction conditions for synthesis of electron donor-[60]fullerene interlocked multiring systems 
Jackson D. Megiatto Junior, Robert Spencer and David I. Schuster
J. Mater. Chem., 2011, Advance Article
DOI: 10.1039/C0JM02154G, Paper

In order to reduce emissions of CO₂, high-performance lithium ion batteries have received a lot of attention as new large-scale power storage systems for eco-cars. In order to improve the electrochemical performance of the all-solid-state cells, an electrochemically favourable electrode–electrolyte interface has to be fabricated. In the case of using solid electrolytes, it is considered that the contact area between active materials and solid electrolytes is smaller than the contact area between active materials and liquid electrolytes because solid electrolytes are not wettable and infiltrative like liquids.

To find a solution to this problem, Masahiro Tatsumisago and colleagues in Japan investigated the softening behavior of a 80Li₂S·20P₂S₅ (mol%) glass electrolyte, and a favorable electrode–electrolyte interface was fabricated by sticking the supercooled liquid state of the 80Li₂S·20P₂S₅ electrolyte on active material particles.

Interested in finding out more?  Read the full article here:

Fabrication of electrode–electrolyte interfaces in all-solid-state rechargeable lithium batteries by using a supercooled liquid state of the glassy electrolytes
Hirokazu Kitaura, Akitoshi Hayashi, Takamasa Ohtomo, Shigenori Hama and Masahiro Tatsumisago
J. Mater. Chem., 2011, Advance Article
DOI: 10.1039/C0JM01090A , Paper

Polar liquid crystals are key components of mixtures for liquid crystals display (LCD) technologies and compounds that exhibit high dielectric anisotropy (Δε), moderate T_NI, and have minimal effect on material’s viscosity are of particular interest for technological applications.

Bryan Ringstrand and Piotr Kaszynski
J. Mater. Chem., 2010, Advance Article
DOI: 10.1039/C0JM02075C, Paper

Bryan Ringstrand and Piotr Kaszynski have developed a new class of nematics with high Δε for display applications and characterized them by thermal and dielectric methods in mixtures with 3 nematic hosts.  These sulfonium zwitterion esters represent a new concept in designing polar additives. They combine the polar zwitterionic fragment that gives rise to a large positive Δε, and shape-shifting ability, which results in high solubility, high effective electric dipole moment µ_eff, and relatively low contribution to rotational viscosity γ.

Interested in knowing more?  Read the full article here; it will be free to access until the 3rd November.

 Aerogels are low-density solids with high open porosity and surface area which have a potential niche in high temperature thermal insulation.  The classic route of synthesis involves two expensive processes, supercritical drying and high temperature imidization. 

In this study, Nicholas Leventis and co-workers in the USA have described polyimide aerogels synthesized via a low temperature process through the rather underutilized reaction of dianhydrides with diisocyanates.  These polyimide aerogels are compared with those obtained by the classic high-temperature amine route and are shown to be chemically identical but morphologically different.  Overall, the isocyanate route has several distinct advantages over the classic route.

Interested in knowing more?  Read the full article here.

Chakkaravarthy Chidambareswarapattar, Zachary Larimore, Chariklia Sotiriou-Leventis, Joseph T. Mang and Nicholas Leventis
J. Mater. Chem., 2010, Advance Article, DOI: 10.1039/C0JM01844A, Paper

A new type of low-cost, flexible and potentially biocompatible photovoltaic system based on aqueous gel which has the potential for energy generation with minimized environmental pollution has been demonstrated by Orlin D. Velev and colleagues in the USA and South Korea.  The article has received widespread media attention including coverage in the ACS’s Chemical & Engineering News.

Hyung-Jun Koo, Suk Tai Chang, Joseph M. Slocik
Rajesh R. Naik and Orlin D. Velev*
J. Mater. Chem., 2011, Advance Article
DOI: 10.1039/C0JM01820A, Paper

This system consists of two layers of photosensitive ionic dyes infused into a hydrogel which sits between an anode and a cathode.  These dyes capture light and work cooperatively to contribute to the photocurrent generating process both on the surface of the working electrode and in the bulk of the gel.  It was also demonstrated that carbon-coated Cu electrodes could replace the expensive Pt counter electrodes and reduce the production cost without loss of efficiency.

Biomimetic or biocompatible solar cells, inspired by “artificial leaves”, are a novel class of photovoltaics currently being developed which utilise Chlorophyll and photosynthetic reaction centers (Photosystem I and II). This system allows for facile hosting of these naturally derived photosensitive molecules and shows performance comparable with or higher than those of other biomimetic or ionic photovoltaic systems reported recently.

Professor Velev explains that  ‘many photoexcitable molecules generate electricity in the right “asymmetric potential” media – used in many organic cells already, but as our medium is water-based it is particularly useful for bioderived molecules’.  However, there are challenges to be solved before these devices can be considered for commercialisation as Professor Velev explains. ‘First, we still have to improve the efficiency of these devices, which is presently very low. Second, we plan to replicate in such devices the ability of the natural leaves to regenerate and replace the organic dye, which will allow us to solve the problems with the long-term stability and performance that are common for all organic photovoltaic devices.  We have clear plans how to address both of these challenges and hope to be able to report the results in future publications’.

This article will be free for the next four weeks! Click here to access it.

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