Author Archives: Ana Belen Jorge Sobrido

MRI Christmas Symposium 2018

We held the MRI Christmas Symposium on the 12th December 2018. It was a great success, with talks from different disciplines from Dentistry to Materials Science, Engineering, Chemistry and Physics. We also had a very interesting poster session, with plenty of fruitful discussions. Thanks to all that contributed to an amazing event and congratulations to the winners for the best talks and posters! Well done!

 

Check our new publication – ACS Omega 2018, 3, 13227-13238

One-Step Synthesis, Structure, and Band Gap Properties of SnO2 Nanoparticles Made by a Low Temperature Nonaqueous Sol–Gel Technique.

ACS Omega, 2018, 3 (10), pp 13227–13238
DOI: 10.1021/acsomega.8b02122

ABSTRACT. Because of its electrically conducting properties combined with excellent thermal stability and transparency throughout the visible spectrum, tin oxide (SnO2) is extremely attractive as a transparent conducting material for applications in low-emission window coatings and solar cells, as well as in lithium-ion batteries and gas sensors. It is also an important catalyst and catalyst support for oxidation reactions. Here, we describe a novel nonaqueous sol–gel synthesis approach to produce tin oxide nanoparticles (NPs) with a low NP size dispersion. The success of this method lies in the nonhydrolytic pathway that involves the reaction between tin chloride and an oxygen donor, 1-hexanol, without the need for a surfactant or subsequent thermal treatment. This one-pot procedure is carried out at relatively low temperatures in the 160–260 °C range, compatible with coating processes on flexible plastic supports. The NP size distribution, shape, and dislocation density were studied by powder X-ray powder diffraction analyzed using the method of whole powder pattern modeling, as well as high-resolution transmission electron microscopy. The SnO2 NPs were determined to have particle sizes between 3.4 and 7.7 nm. The reaction products were characterized using liquid-state 13C and 1H nuclear magnetic resonance (NMR) that confirmed the formation of dihexyl ether and 1-chlorohexane. The NPs were studied by a combination of 13C, 1H, and 119Sn solid-state NMR as well as Fourier transform infrared (FTIR) and Raman spectroscopy. The 13C SSNMR, FTIR, and Raman data showed the presence of organic species derived from the 1-hexanol reactant remaining within the samples. The optical absorption, studied using UV–visible spectroscopy, indicated that the band gap (Eg) shifted systematically to lower energy with decreasing NP sizes. This unusual result could be due to mechanical strains present within the smallest NPs perhaps associated with the organic ligands decorating the NP surface. As the size increased, we observed a correlation with an increased density of screw dislocations present within the NPs that could indicate relaxation of the stress. We suggest that this could provide a useful method for band gap control within SnO2 NPs in the absence of chemical dopants.

“Colombian Waste Biomass to Advanced Energy Materials” project hortlisted for the Newton Prize, British Council.

Very happy to find out that our Newton Institutional Link collaborative project with Magda Titirici, from QMUL and Diana  Lopez from Universidad de Antioquia on “Colombian Waste Biomass to Advanced Energy Materials” has been shortlisted for the Newton Prize, British Council.