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Thermal and Photochemical Electrocyclic Reactions: Overview

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Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.

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Revealing Intrinsic Functionalization, Structure, and Photo-Thermal Oxidation in Hexagonal Antimonene.

Marta Alcaraz¹, Michael Fickert², Christian Dolle³

¹Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Paterna, 46980, Spain.

Small (Weinheim an Der Bergstrasse, Germany)

|October 15, 2024

Summary

Few-layer antimonene (FLA) hexagons possess intrinsic thiol functionalization, protecting them from oxidation. Their structure and properties, including thickness-dependent Raman spectra, offer potential for 2D heterostructures.

Keywords:

2D Pnictogens antimonene functionalization oxidation photo‐thermal properties

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Area of Science:

Materials Science
Nanotechnology
2D Materials

Background:

Antimonene is a promising post-graphene 2D material with potential applications in optoelectronics, energy storage, catalysis, sensing, and biomedicine.
Previous research focused on scalable production of few-layer antimonene (FLA) hexagons via colloidal methods.
The oxidation behavior, inner structure, and photothermal properties of FLA hexagons remained largely unexplored.

Purpose of the Study:

To investigate the oxidation behavior, intrinsic structure, and photothermal properties of few-layer antimonene (FLA) hexagons.
To understand the influence of surface functionalization on FLA hexagon stability.
To explore the potential of FLA hexagons as building blocks for advanced 2D heterostructures.

Main Methods:

Synthesis of few-layer antimonene (FLA) hexagons using a colloidal approach.
Characterization using cross-sectional scanning transmission electron microscopy energy dispersive X-ray spectroscopy (STEM-EDX).
Analysis via temperature-dependent X-ray photoelectron spectroscopy (XPS), selected area electron diffraction (SAED), and Raman spectroscopy (temperature and laser power-dependent).

Main Results:

FLA hexagons exhibit intrinsic surface functionalization with alkyl thiols, providing protection against oxidation.
Inner defects related to crystal formation during synthesis were identified.
Raman spectroscopy revealed thickness-dependent behavior: thinner flakes (<20 nm) showed a blueshift and intensity decrease, while thicker flakes exhibited a redshift.

Conclusions:

The surface functionalization of FLA hexagons plays a crucial role in their oxidation resistance.
Understanding the inner structure and defects is key to controlling FLA properties.
FLA hexagons are suitable building blocks for 2D heterostructures, including combinations with antimonene oxides and other 2D materials.