Type

Journal Article

Authors

Michael A. Morris
P M G Nambissan
Justin D. Holmes
Tandra Ghoshal
Atul V Thorat

Subjects

Physics

Topics
electrons doped nanoparticles formation particle size atoms europium positrons ions cerium compounds energy quantum confinement nanoparticles cerium oxide experimental surface vacancies

A positron annihilation spectroscopic investigation of europium-doped cerium oxide nanoparticles. (2013)

Abstract Doping in ceria (CeO2) nanoparticles with europium (Eu) of varying concentrations (0, 0.1, 0.5, …, 50 atom%) is studied using complementary experimental techniques and novel observations were made during the investigation. The immediate observable effect was a distinct reduction in particle sizes with increasing Eu concentration attributed to the relaxation of strain introduced due to the replacement of Ce(4+) ions by Eu(3+) ions of larger radius. However, this general trend was reversed in the doping concentration range of 0.1-1 atom% due to the reduction of Ce(4+) to Ce(3+) and the formation of anion vacancies. Quantum confinement effects became evident with the increase of band gap energy when the particle sizes reduced below 7-8 nm. Positron annihilation studies indicated the presence of vacancy type defects in the form of vacancy clusters within the nanoparticles. Some positron annihilation was also seen on the surface of crystallites as a result of diffusion of thermalized positrons before annihilation. Coincidence Doppler broadening measurements indicated the annihilation of positrons with electrons of different species of atoms and the characteristic S-W plot showed a kink-like feature at the particle sizes where quantum confinement effects began.
Collections Ireland -> University College Cork -> PubMed
Ireland -> University College Cork -> College of Science, Engineering and Food Science
Ireland -> University College Cork -> Tyndall National Institute
Ireland -> University College Cork -> Tyndall National Institute - Journal Articles
Ireland -> University College Cork -> Chemistry
Ireland -> University College Cork -> Chemistry - Journal Articles
Ireland -> University College Cork -> Research Institutes and Centres

Full list of authors on original publication

Michael A. Morris, P M G Nambissan, Justin D. Holmes, Tandra Ghoshal, Atul V Thorat

Experts in our system

1
Michael A. Morris
University College Cork
Total Publications: 164
 
2
Justin D. Holmes
University College Cork
Total Publications: 287
 
3
Tandra Ghoshal
University College Cork
Total Publications: 32
 
4
Atul V. Thorat
University College Cork
Total Publications: 3