Phonon density of states in lanthanide-based nanocrystals

Li, Z. H.; Hudry, D.; Heid, R.; Said, A. H.; Le, M. D.; Popescu, R.; Gerthsen, D.; Merz, M.; Krämer, K. W.; Busko, D.; Howard, I. A.; Richards, B. S.; Weber, F. (2020). Phonon density of states in lanthanide-based nanocrystals. Physical review. B - condensed matter and materials physics, 102(16), p. 165409. American Physical Society 10.1103/PhysRevB.102.165409

[img] Text
318_PhysRevB.102.165409.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (3MB) | Request a copy

We report a combined inelastic neutron- and x-ray-scattering study of the phonon density of states of the nano- and microcrystalline lanthanide-based materials NaY0.8Yb0.18Er0.02F4 and NaGd0.8Yb0.18Er0.02F4. While large (20 nm) nanocrystals display the same vibrational spectra as their microcrystalline counterparts, we find an enhanced phonon density of states at low energies, E≤15meV, in ultrasmall (5 nm) NaGd0.8Yb0.18Er0.02F4 nanocrystals which we assign to an increased relative spectral weight of surface phonon modes. Based on our observations for ultrasmall nanocrystals, we rationalize that an increase of the phonon density of states in large nanocrystals due to surface phonons is too small to be observed in the current measurements. The experimental approach described in this paper constitutes a step toward the rationalization of size effects on the modification of the absolute upconversion quantum yield of upconverting nanocrystals.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Krämer, Karl

Subjects:

500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

1098-0121

Publisher:

American Physical Society

Language:

English

Submitter:

Karl Krämer

Date Deposited:

17 Nov 2020 09:47

Last Modified:

17 Nov 2020 17:58

Publisher DOI:

10.1103/PhysRevB.102.165409

BORIS DOI:

10.7892/boris.148070

URI:

https://boris.unibe.ch/id/eprint/148070

Actions (login required)

Edit item Edit item
Provide Feedback