Journal of Materials Chemistry Blog

Researchers from University of Virginia have investigated the effects of aromatic substituents in boron diketones.

All of the dyes studied except BF₂mbm (i.e. those with aromatic rather than aliphatic substitution) showed emission changes upon mechanical perturbation. Aromatics with increased π conjugation led to more dramatic, red-shifted fluorescence. Their recovery is also significantly affected by the aromatic substituents.

Interested to know more? Why not read the full article for free:  T. Liu, A. D. Chien, J. Lu, G. Zhang and C. L. Fraser, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04326e (Advance Article)

Researchers at Nanyang Technological University have synthesised organic single crystals with thicknesses ranging from a few monolayers to micrometres by an “Organic Crystal Cleavage” method.

Ultrathin F₁₆CuPc and pentacene single crystal field-effect transistors were subsequently fabricated and the corresponding thickness dependence of mobility was investigated. The charges induced in the metal–semiconductor interface reduced the contact barrier. This, in turn, allowed measurement of the values of mobility that precisely reflected the real transport properties of organic semiconductors.

Interested to know more? Why not read the full article for free: H. Jiang, K. Jie Tan, K. K. Zhang, X. Chen and C. Kloc, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04383d (Advance Article)

The thermal conductivities of blend-PI films containing ZnO nanoparticles have been investigated by researchers from Tokyo Institute of Technology for future electric and electronic applications.

The blend films obtained were composed of sulfur- and fluorine- containing PIs and exhibited distinct microphase-separated structures with a vertical double percolation morphology. These films had two principle advantages over conventional homo-PI systems. The smaller ZnO content in the blend-PI films conferred a larger thermal conductivity. Additionally, the thermal conductivity was larger in pristine (without ZnO nanoparticles) blend-PI films than homo-PI films. A higher thermal conductivity is advantageous for application in polymer dielectric materials, as it allows for better flexibility, light weight and higher electric insulation properties.

Interested to know more? Why not read the full article for free: D. Yorifuji and S. Ando, J. Mater. Chem., 2011, 21, 4402.

Researchers from Georgia Institute of Technology and University of Washington have synthesised dithienopyrrole–quinoxaline/pyridopyrazine donor–acceptor polymers by Stille coupling reactions.

It was found that the pyridopyrazine moiety is a stronger acceptor than quinoxaline and that the extended benzophenazine and dibenzopyridoquinoxaline species are stronger acceptors than quinoxaline and pyridopyrazine, respectively. When used in field effect transistors, average hole mobilities of up to ca 3.0 × 10^–4 cm² V^–1 s^–1 were obtained. Bulk heterojunction photovoltaic devices made from blends of the benzo[a,c]phenazine-based polymer gave average power conversion efficiencies of 1.4%.

Interested to know more? Why not read the full article for free: X. Zhang, J. W. Shim, S. P. Tiwari, Q. Zhang, J. E. Norton, P.-T. Wu, S. Barlow, S. A. Jenekhe, B. Kippelen, J.-L. Brédas and S. R. Marder, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04290k (Advance Article)

Researchers from Chinese Academy of Sciences have prepared mesoporous hollow TiO₂ microspheres via a facile solvothermal method using glycine as a multifunctional smart template.

The glycine serves as a sacrificial template, complexing agent and water supplier in the TiO₂ microsphere synthesis and the cavity volume can be easily controlled by varying the mass of crude glycine used. Eu-doped TiO₂ hollow spheres have been made by this method and they exhibit stronger photoluminescence – due to their unique microstructures – compared to conventional, hydrothermal samples.

Interested to know more? Why not read the full article for free:  S. Ding, F. Huang, X. Mou, J. Wu and X. Lü, J. Mater. Chem., 2011, DOI: 10.1039/c0jm03628e (Advance Article)

Researchers from University of Idaho have synthesized and characterized 4-(trifluoromethyl and pentafluorosulfanyl)-substituted mono- and poly-1,2,3-triazole compounds.

These triazoles can be obtained in moderate to good yield from Cu(I) catalyzed 1,3-dipolar cycloaddition reaction of various azides with trifluoromethyl- and pentafluorosulfanyl-substituted acetylenes. The fluorinated triazene-(1,2,3-triazole) compounds exhibit the best detonation properties – comparable to that of TNT – and all bar one of them have high thermal stability (>270 °C) and are insensitive to impact.

Interested to know more? Why not read the full article for free: S. Garg and J. M. Shreeve, J. Mater. Chem., 2011, DOI: 10.1039/c0jm04229c (Advance Article)