# Thermally Driven Formation of Multiphase, Mixed-Dimensional Architectures from TaSe3 Nanoribbons

## TL;DR

This paper shows how heating TaSe3 nanoribbons creates complex 0D-1D mixed-phase structures through a unique thermal transformation process.

## Contribution

The study reveals a novel core–shell transformation mechanism in TaSe3 nanoribbons driven by nanoscale confinement effects.

## Key findings

- TaSe3 nanoribbons convert into multiphase, mixed-dimensional (0D–1D) tantalum–selenium architectures upon heating.
- Core–shell transformation results in Ta-rich nanoparticles encapsulated in porous TaSe2 tubes.
- Nanoscale confinement effects significantly alter the decomposition pathway compared to bulk TaSe3.

## Abstract

Tantalum–selenium compounds, particularly TaSe2 and TaSe3, are promising materials for electronics
and
quantum technologies due to their charge density wave and topological
properties, and they are also candidates for energy storage and electrocatalysis
applications. In this study, we investigate the thermally driven structural
evolution of TaSe3 nanoribbons using in situ scanning transmission electron microscopy (STEM). Low-kV STEM experiments
reveal a complex nanoscale transformation pathway in which TaSe3 nanoribbons convert into multiphase, mixed-dimensional (0D–1D)
tantalum–selenium architectures. Aberration-corrected STEM
enables direct visualization of the underlying atomic rearrangements,
while electron energy loss spectroscopy and DFT calculations corroborate
the identity and stability of the product phases. Our results uncover
a detailed mechanism: selenium loss from TaSe3 nanoribbons
initiates surface conversion to TaSe2, which, as temperature
increases, progressively continues into the nanoribbon interior. Thicker
regions of TaSe2 delaminate and detach from the core material,
forming a porous TaSe2 shell. At 1200 °C, the core
restructures into discrete ∼20 nm Ta-self-intercalated
TaSe2 nanoparticles. This core–shell transformation,
driven by nanoscale confinement effects, differs markedly from the
bulk decomposition pathway of TaSe3 and highlights the
impact of modulating selenium loss, tantalum intercalation, and the
stability of intermediate structures through confinement effects.
The resulting 0D–1D heterostructure of Ta-rich nanoparticles
encapsulated within porous TaSe2 tubes represents surprising
and emergent complexity in a binary system. These mechanistic insights
demonstrate how the controlled thermolysis of a readily accessible
metal trichalcogenide precursor can yield complex, low-dimensional
chalcogenide architectures.