Cage-Like Nanoclusters of ZnO Probed by Time-Resolved Photoelectron Spectroscopy and Theory.
Zinc oxide nanoclusters have been predicted as promising building blocks for cluster-assembled materials with unprecedented properties. Here, for the first time these clusters are probed by time-resolved photoelectron spectroscopy and characterized in detail by density functional theory. Their validity as building blocks for cluster-assembled materials is confirmed via rigid cage-like structures facilitating three-dimensional aggregation in combination with large band gaps that are nevertheless significantly lower than any known ZnO polymorph. In addition, electron-hole pair localization in the excited state of the cluster anions combined with their structural rigidity leads to extraordinary long-lived states above the band gap virtually independent of the cluster size, defying the rule "every atom counts".
‡Fachbereich für Physik, Universität Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.
Julian
J
Heinzelmann
‡Fachbereich für Physik, Universität Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.
Alexander
A
Koop
‡Fachbereich für Physik, Universität Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.
Sebastian
S
Proch
‡Fachbereich für Physik, Universität Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.
Gerd F
GF
Ganteför
†Otto-Schott-Institut für Materialforschung, Friedrich-Schiller Universität Jena, Löbdergraben 32, 07743 Jena, Germany.
Roman
R
Łazarski
†Otto-Schott-Institut für Materialforschung, Friedrich-Schiller Universität Jena, Löbdergraben 32, 07743 Jena, Germany.
Marek
M
Sierka
band gap; cluster-assembled materials (CAMs); electron−hole pair localization; pump−probe spectroscopy; time-dependent density functional theory (TD−DFT)