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Engineering of Facets, Band Structure, and Gas‐Sensing Properties of Hierarchical Sn 2+ ‐Doped SnO 2 Nanostructures
Author(s) -
Wang Hongkang,
Dou Kunpeng,
Teoh Wey Yang,
Zhan Yawen,
Hung Tak Fu,
Zhang Feihu,
Xu Jiaqiang,
Zhang Ruiqin,
Rogach Andrey L.
Publication year - 2013
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201300303
Subject(s) - materials science , nanostructure , doping , oxidizing agent , ostwald ripening , nanotechnology , fermi level , semiconductor , hydrothermal circulation , fluorine , band gap , chemical engineering , chemical physics , optoelectronics , electron , organic chemistry , chemistry , physics , quantum mechanics , engineering , metallurgy
Hierarchical SnO 2 nanoflowers, assembled from single‐crystalline SnO 2 nanosheets with high‐index (11 $ \bar 3 $ ) and (10 $ \bar 2 $ ) facets exposed, are prepared via a hydrothermal method using sodium fluoride as the morphology controlling agent. Formation of the 3D hierarchical architecture comprising of SnO 2 nanosheets takes place via Ostwald ripening mechanism, with the growth orientation regulated by the adsorbate fluorine species. The use of Sn(II) precursor results in simultaneous Sn 2+ self‐doping of SnO 2 nanoflowers with tunable oxygen vacancy bandgap states. The latter further results in the shifting of semiconductor Fermi levels and extended absorption in the visible spectral range. With increased density of states of Sn 2+ ‐doped SnO 2 selective facets, this gives rise to enhanced interfacial charge transfer, that is, high sensing response, and selectivity towards oxidizing NO 2 gas. The better gas sensing performance over (10 $ \bar 2 $ ) compared to (11 $ \bar 3 $ ) faceted SnO 2 nanostructures is elucidated by surface energetic calculations and Bader analyses. This work highlights the possibility of simultaneous engineering of surface energetics and electronic properties of SnO 2 based materials.