Abstract
MoO3 nanoribbons were studied under different pressure conditions
ranging from 0 to 21 GPa at room temperature. The effect of the applied
pressure on the spectroscopic and morphologic properties of the MoO3
nanoribbons was investigated by means of Raman spectroscopy and scanning
electron microscopy techniques. The pressure dependent Raman spectra of
the MoO3 nanoribbons indicate that a structural phase transition occurs
at 5 GPa from the orthorhombic alpha-MoO3 phase (Pbnm) to the monoclinic
MoO3-II phase (P-21/m), which remains stable up to 21 GPa. Such phase
transformation occurs at considerably lower pressure than the critical
pressure for alpha-MoO3 microcrystals (12 GPa). We suggested that the
applanate morphology combined with the presence of crystalline defects
in the sample play an important role in the phase transition of the MoO3
nanoribbons. Frequencies and linewidths of the Raman bands as a function
of pressure also suggest a pressure induced morphological change and the
decreasing of the nanocrystal size. The observed spectroscopic changes
are supported by electron microscopy images, which clearly show a
pressure-induced morphologic change in MoO3 nanoribbons. (C) 2017
Elsevier B.V. All rights reserved.
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