Ferroelectric bismuth-titanate nanoplatelets and nanowires with a new crystal structure
Two different morphologies of ferroelectric bismuth titanate (Bi 4 Ti 3 O 12 ) nanoparticles, i.e. , nanoplatelets and nanowires, were synthesized by changing the concentration of NaOH during a hydrothermal treatment of precipitated Ti 4+ and Bi 3+ ions. The nanoparticles' crystal structures we...
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Published in | Nanoscale Vol. 14; no. 9; pp. 3537 - 3544 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
07.03.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | Two different morphologies of ferroelectric bismuth titanate (Bi
4
Ti
3
O
12
) nanoparticles,
i.e.
, nanoplatelets and nanowires, were synthesized by changing the concentration of NaOH during a hydrothermal treatment of precipitated Ti
4+
and Bi
3+
ions. The nanoparticles' crystal structures were characterized using atomic-resolution imaging with a
C
S
-probe-corrected scanning-transmission electron microscope in combination with X-ray diffractometry and Raman spectroscopy. The nanoplatelets (10 nm thick and from 50 nm to 200 nm wide) exhibit the Aurivillius-type layered-perovskite crystal structure that is characteristic of Bi
4
Ti
3
O
12
, whereas the nanowires (from 15 nm to 35 nm wide and from several hundreds of nm to several μm long) exhibit an entirely new structure with an orthorhombic unit cell (
a
= 3.804(1) Å,
b
= 11.816(3) Å, and
c
= 9.704(1) Å). The nanowire structure is composed of two structural layers alternating along the orthorhombic
c
-direction: a structural layer composed of two parallel layers of Bi atoms that resembles the (Bi
2
O
2
)
2+
layer of the Aurivillius structure, and a structural layer composed of two parallel layers of Ti atoms, where every sixth Ti is replaced with Bi. Observations of the ferroelectric domains with transmission electron and piezo-response force microscopy indicated the ferroelectric nature of both nanostructures. The nanowire structure is a metastable polymorph of the bismuth titanate stabilized at the nanoscale. With annealing at temperatures above 500 °C the nanowire structure topotactically transforms into the Aurivillius structure.
Ferroelectric Bi
4
Ti
3
O
12
nanoparticles can be hydrothermally synthesized in two distinct morphologies,
i.e.
, nanoplatelets and nanowires. The nanowires exhibit a new layered crystal structure that has not been described before. |
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Bibliography: | Electronic supplementary information (ESI) available: List of materials used and additional information on the characterization methods, LeBail profile fitting of the XRD pattern, Raman spectroscopy, TEM/XRD of annealed nanowires, TEM observation of domain structure, and PFM observation of switching and inducing ferroelectric domains. See DOI 10.1039/d2nr00307d ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2040-3364 2040-3372 |
DOI: | 10.1039/d2nr00307d |