The focus of my research is electronic structure calculations with special attention to the modeling of nanostructures systems and their interaction with the surfaces. In particular I am interested in modeling various properties of bulk, surfaces, nano objects of inorganic and organic molecular materials, which are potential candidates for novel and environmental-friendly technologies. My calculations are performed by means of Density Functional Theory, and I utilize several methods for the computation of different properties as well as dimension of the system (like 1D: molecules/clusters, 2D: thin films, and 3D: periodic crystals). I work in close collaboration with experimental groups both in Norway and from other countries.
At present I am working as a senior researcher in the SiALD (Novel Silicon deposition processes by ALD) project, funded by Research Council of Norway. The aim of the project is to develop cheap, scalable processes for silicon containing materials applicable in photovoltaic processes of next generation solar cells. My role on this project is to hunt for potential Si-precursor that shows positive indications for ALD reactivity and to understand/explain the mechanism behind the Si-based ALD processes.
- Bianchini, Federico; Fjellvåg, Helmer & Vajeeston, Ponniah (2018). A first principle comparative study of the ionic diffusivity in LiAlO<sub>2</sub> and NaAlO<sub>2</sub> polymorphs for solid-state battery applications. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 20(15), s 9824- 9832 . doi: 10.1039/c8cp00715b
- Eidsvåg, Håkon; Rasukkannu, Murugesan; Vajeeston, Ponniah & Velauthapillai, Dhayalan (2018). Bandgap engineering in CsSnxPb(1−x)I3 and their influence on light absorption. Materials letters (General ed.). ISSN 0167-577X. 218, s 253- 256 . doi: 10.1016/j.matlet.2018.02.021
- El-Kharbachi, Abdelouahab; Hu, Yang; Yoshida, Koji; Vajeeston, Ponniah; Kim, Sangryun; Sørby, Magnus Helgerud; Orimo, Shin-Ichi; Fjellvåg, Helmer & Hauback, Bjørn (2018). Lithium ionic conduction in composites of Li(BH4)0.75I0.25 and amorphous 0.75Li2S·0.25P2S5 for battery applications. Electrochimica Acta. ISSN 0013-4686. 278, s 332- 339 . doi: 10.1016/j.electacta.2018.05.041
- Fjellvåg, Øystein Slagtern; Armstrong, Jeff; Vajeeston, Ponniah & Sjåstad, Anja Olafsen (2018). New Insights into Hydride Bonding, Dynamics, and Migration in La2LiHO3 Oxyhydride. Journal of Physical Chemistry Letters. ISSN 1948-7185. s 353- 358 . doi: 10.1021/acs.jpclett.7b03098 Show summary
- Rasukkannu, Murugesan; Velauthapillai, Dhayalan & Vajeeston, Ponniah (2018). A first-principle study of the electronic, mechanical and optical properties of inorganic perovskite Cs2SnI6 for intermediate-band solar cells. Materials letters (General ed.). ISSN 0167-577X. 218, s 233- 236 . doi: 10.1016/j.matlet.2018.02.083
- Vajeeston, Ponniah; Fjellvåg, Helmer & Nilsen, Ola (2018). Search for potential precursors for Si-atomic layer deposition- a quantum chemical study. Materials letters (General ed.). ISSN 0167-577X. 216, s 189- 192 . doi: https://doi.org/10.1016/j.matlet.2018.01.040 Show summary
- Bianchini, Federico; Fjellvåg, Helmer & Vajeeston, Ponniah (2017). First-principles study of the structural stability and electrochemical properties of Na2MSiO4 (M = Mn, Fe, Co and Ni) polymorphs. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 19(22), s 14462- 14470 . doi: 10.1039/c7cp01395g
- Lundvall, Fredrik; Wragg, David; Vajeeston, Ponniah; Dietzel, Pascal D.C. & Fjellvåg, Helmer (2017). Ab initio structure solution and thermal stability evaluation of a new Ca(II) 3D coordination polymer using synchrotron powder X-ray diffraction data. CrysteEngComm. ISSN 1466-8033. 19(39), s 5857- 5863 . doi: 10.1039/c7ce01389b Show summary
- Nagell, Marius Uv; Slawinski, Wojciech Andrzej; Vajeeston, Ponniah; Fjellvåg, Helmer & Sjåstad, Anja Olafsen (2017). Temperature induced transitions in La-4(Co1-xNix)(3)O-10 (+) (delta); oxygen stoichiometry and mobility. Solid State Ionics. ISSN 0167-2738. 305, s 7- 15 . doi: 10.1016/j.ssi.2017.04.006
- Hu, Yang; El-Kharbachi, Abdelouahab; Yoshida, Koji; Vajeeston, Ponniah; Sørby, Magnus Helgerud; Orimo, Shin-Ichi; Fjellvåg, Helmer & Hauback, Bjørn (2017). Ionic Properties of the borohydride-sulfide Mixed System for All-Solid Li-Ion Batteries.