Real-time direct transmission electron microscopy imaging of phase and morphology transformation from solid indium oxide hydroxide to hollow corundum-type indium oxide nanocrystallites. Issue 25 (17th June 2019)

• Record Type: Journal Article
• Authors: Schlicker, Lukas; Popescu, Radian; Bekheet, Maged F.; Doran, Andrew; Gerthsen, Dagmar; Gurlo, Aleksander
• Is Part Of: Nanoscale. Volume 11:Issue 25(2019)
• Page Start: 12242
• Page End: 12249
• Publication Date: 2019-06-17
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr02115a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : This work clarifies the mechanism of the formation of hollow nanostructures (nanotubes and nanospheres) during the InOOH to rh-In2 O3 transformation. Abstract : A time-resolved series of high-resolution transmission electron microscopy (HRTEM) images are used to monitor phase and morphology transformation of rod-like and spherical particles with the initial orthorhombic InOOH phase in situ under continuous illumination with high-energy electrons in a transmission electron microscope. For both particle types, the electron-beam irradiation induces a fast InOOH to rh-In2 O3 decomposition accompanied by the formation of voids within the particle/rod center. After illumination time intervals of about 1–2 min ( i.e. electron dose 6.3–12.6 × 10 7 e nm −2 ) for particles and 8 min (4.3 × 10 8 e nm −2 ) for rods, respectively, several small empty cavities become visible in the particle/rod center. The cavities coalesce and form a large hollow space/canal after further illumination. Time-resolved in situ HRTEM unambiguously shows that the formation of internal voids in both nanoparticle types is a consequence of the structural InOOH-to-rh-In2 O3 phase transition that starts at the surface of the corresponding particle. The as-formed oxide phase encapsulates the untransformed hydroxylated phase. Its decomposition does not follow the Kirkendall mechanism; the matter transferred outwards is removed in the form of water, leading to void formation inside without an increase of the particle size.