Browsing by Author "Wang, Hongliang"

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Energy Band Gap Modulation in Nd-Doped BiFeO3/SrRuO3 Heteroepitaxy for Visible Light Photoelectrochemical Activity
(2019-01-09)
Tan, Kok Hong
;
Chen, Yun-Wen
;
Chien Nguyen Van
;
Wang, Hongliang
;
Chen, Jhih-Wei
The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer and thus altering the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principle calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
Self-assembled gold nanostructures in complex oxide thin films
(2020-01-01)
Wang, Hongliang
;
Yen, Min
;
Er, Xiaokuo
;
Liu, Pingping
;
Wan, Farong
Recently, noble metal-complex oxide nanocomposites with a high interface-to-volume ratio have attracted considerable interest for their potential applications in advanced devices. In this work, Nb:SrTiO3 epitaxial thin films embedded with different ratios of Au nanophase were fabricated using pulsed laser deposition. Detailed heterostructures at an atomic scale have been investigated based on advanced transmission electron microscopy. The results reveal that the pattern tunability of Au nanostructures can be realized by controlling the volume ratios between Au and Nb:SrTiO3, resulting in the manipulation of absorption characteristics in the visible light region. It is suggested that elastic energy and surface energy anisotropy are important factors to control the growth of the present Au/Nb:SrTiO3 heterostructures. This work offers a desirable platform to design nano composites with novel optical properties.