Surface exciton separation in photoexcited MgO nanocube powders

Sternig A, Stankic S, Mueller M, Siedl N, Diwald O (2012)

Publication Language: English

Publication Type: Journal article

Publication year: 2012

Journal

Nanoscale Royal Society of Chemistry

Original Authors: Sternig A, Stankic S, Müller M, Siedl N, Diwald O

Publisher: Royal Society of Chemistry

Book Volume: 4

Pages Range: 7494-7500

Journal Issue: 23

DOI: 10.1039/c2nr31844j

Abstract

In MgO nanocube powders surface excitons can separate and the resulting charge carriers provide reactive adsorption sites at well-defined surface elements. We employed photoluminescence (PL) emission bands originating from the photoexcitation of nanocube corners and edges as quantitative probes to explore their chemical reactivity towards molecular hydrogen. Surface excitons which form at corners and edges exhibit similar cross-sections for separation in vacuum. The separation of edge excitons, however, is significantly enhanced in hydrogen atmosphere when hydrogen adsorption occurs as a simultaneous surface process. The electronic structure of MgO nanocube edges which split hydrogen heterolytically upon generation of surface hydroxyls and hydrides is unaffected by the photoexcitation of corners. Respective edges, however, are efficient absorption sites for UV photons. Transfer of exciton energy to oxygen ions in corners is followed by exciton separation which transforms corner ions into surface radicals leading to a well-defined starting point for the site selective functionalization of metal oxide nanostructures.

Authors with CRIS profile

Andreas Sternig Lehrstuhl für Partikelsynthese (LFG) Nicolas Siedl Professur für Partikelsynthese Oliver Diwald Professur für Partikelsynthese

Additional Organisation(s)

Exzellenz-Cluster Engineering of Advanced Materials (EAM)

Involved external institutions

National Center for Scientific Research / Centre national de la recherche scientifique (CNRS) FR France (FR) Technische Universität Wien / Vienna University of Technology AT Austria (AT)

How to cite

APA:

Sternig, A., Stankic, S., Mueller, M., Siedl, N., & Diwald, O. (2012). Surface exciton separation in photoexcited MgO nanocube powders. Nanoscale, 4(23), 7494-7500. https://doi.org/10.1039/c2nr31844j

MLA:

Sternig, Andreas, et al. "Surface exciton separation in photoexcited MgO nanocube powders." Nanoscale 4.23 (2012): 7494-7500.

BibTeX: Download