Direct imaging of structural changes induced by ionic liquid gating leading to engineered three-dimensional meso-structures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30076292.
- Also identified by DOI 10.1038/s41467-018-05330-1 and PMC identifier 6076294.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The controlled transformation of materials, both their structure and their physical properties, is key to many devices. Ionic liquid gating can induce the transformation of thin-film materials over long distances from the gated surface. Thus, the mechanism underlying this process is of considerable interest. Here we directly image, using in situ, real-time, high-resolution transmission electron microscopy, the reversible transformation between the oxygen vacancy ordered phase brownmillerite SrCoO<sub>2.5</sub> and the oxygen ordered phase perovskite SrCoO<sub>3</sub>. We show that the phase transformation boundary moves at a velocity that is highly anisotropic, traveling at speeds ~30 times faster laterally than through the thickness of the film. Taking advantage of this anisotropy, we show that three-dimensional metallic structures such as cylinders and rings can be realized. Our results provide a roadmap to the construction of complex meso-structures from their exterior surfaces.