Research project: Hector: Sol-gel chemistry to nitride materials

Nitride materials are much less well studied than oxides, but have been the focus of heavy interest for several years due to the wealth of technological applications for which they have found to be useful.

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Project Overview

Sol-gel synthesis develops polymeric or particulate structures in solution, then links them into a gel as a means of controlling the shape or internal structure of materials, typically oxides. The technique is poorly developed in non-oxide materials, but developing new routes has the potential to deliver nitride materials in morphologies that cannot otherwise be accessed. We have developed routes based on ammonia or primary amines as the cross-linking agent to control the gelation process and applied these to a number of systems.

We have shown that sol-gel synthesis of nitride materials can lead to the controlled formation of transition metal nitrides as nanostructured materials, aerogels and monolithic objects. We have developed methods to deposit films and inverse opal films of titanium and silicon nitrides by dip coating. We have doped lanthanide elements into silicon nitride to produce high stability phosphors. We can also produce monolithic gels and have used supercritical drying to make silicon nitride aerogels (very low density spongy materials).


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The same chemistry as used in sol-gel processing is also effective for production of nanocrystalline metal nitride powders, giving access to many of the materials we use in charge storage applications. It also has the advantage that the metal oxidation state can often be maintained from the precursor to the nitride material, we have used this to prepare novel nitrogen-rich Hf3N4 and Ta3N5 high pressure phases.

Related research groups


Publications associated with this project from The University of Southampton's electronic library (e-prints):

Key Publications

Salamat, Ashkan, Woodhead, Katherine, Shah, S. Imran U., Hector, Andrew Lee and McMillan, Paul F. (2014) Synthesis of U3Se5and U3Te5type polymorphs of Ta3N5by combining high pressure–temperature pathways with a chemical precursor approach. Chemical Communications, 50, (70), 10041-10044. (doi:10.1039/c4cc05147e).
Mallinson, Christopher F., Gray, Benjamin M., Hector, Andrew L., McLachlan, Martyn A. and Owen, John R. (2013) Templated non-oxide sol-gel preparation of well-ordered macroporous (inverse opal) Ta3N5 films. Inorganic Chemistry, 52, (17), 9994-9999. (doi:10.1021/ic4012718).
Salamat, Ashkan, Hector, Andrew Lee, Gray, Benjamin M., Kimber, Simon A.J., Bouvier, Pierre and McMillan, Paul F. (2013) Synthesis of tetragonal and orthorhombic polymorphs of Hf3N4 by high pressure annealing of a pre-structured nanocrystalline precursor. Journal of the American Chemical Society, 135, (25), 9503-9511. (doi:10.1021/ja403368b).
Bailey, Edward, Thompson, Nicole M., Hector, Andrew L., Crozier, Peter, Petuskey, William T. and McMillan, Paul F. (2011) Mechanical properties of titanium nitride nanocomposites produced by chemical precursor synthesis followed by high-P,T treatment. Materials, 4, (10), 1747-1762. (doi:10.3390/ma4101747).
Jackson, Andrew W. and Hector, Andrew L. (2007) A nonoxidic sol-gel route to titanium nitride and carbonitride films by primary amine condensation. Journal of Materials Chemistry, 17, (10), 1016-1022. (doi:10.1039/b616067k).
Hassan, Shereen, Hector, Andrew L. and Kalaji, Ali (2011) Sol–gel processing of silicon nitride films from Si(NHMe)4 and ammonia. Journal of Materials Chemistry, 21, (17), 6370-6374. (doi:10.1039/C1JM10127G).
Hector, Andrew L. (2007) Materials synthesis using oxide free sol–gel systems. Chemical Society Reviews, 36, (11), 1745-1753. (doi:10.1039/b608838b).
Hassan, Shereen, Hector, Andrew L., Hyde, Jason R., Kalaji, Ali and Smith, David C. (2008) A non-oxide sol–gel route to synthesise silicon imidonitride monolithic gels and high surface area aerogels. Chemical Communications, 42, 5304-5306. (doi:10.1039/b810317h).
Gray, Benjamin M., Hassan, Shereen, Hector, Andrew L., Kalaji, Ali and Mazumder, Baishakhi (2009) Template infiltration routes to ordered macroporous TiN and SiNxFilms. Chemistry of Materials, 21, (18), 4210-4215. (doi:10.1021/cm900753f).
Hassan, Shereen, Carravetta, Marina, Hector, Andrew L. and Stebbings, Laura A. (2009) Nonoxide Sol-Gel Synthesis of Terbium-Doped Silicon Nitride Phosphors. Journal of the American Ceramic Society, 93, (4), 1069-1073. (doi:10.1111/j.1551-2916.2009.03499.x).


Members of staff associated with this project: