Bandgap‐Tunable Preparation of Smooth and Large Two‐Dimensional Antimonene

Abstract

As a highly stable band gap semiconductor, antimonene is an intriguing two-dimensional (2D) material in optoelectronics. However, its short layer distance and strong binding energy make it challenging to prepare high-quality large 2D antimonene; therefore, its predicted tunable band gap has not been experimentally confirmed. Now, an approach to prepare smooth and large 2D antimonene with uniform layers that uses a pregrinding and subsequent sonication-assisted liquid-phase exfoliation process has been established. Mortar pregrinding provides a shear force along the layer surfaces, forming large, thin antimony plates, which can then easily be exfoliated into smooth, large antimonene, avoiding long sonication times and antimonene destruction. The resulting antimonene also enabled verification of the tunable band gap from 0.8 eV to 1.44 eV. Hole extraction and current enhancement by about 30 % occurred when the antimonene was used as a hole transport layer in perovskite solar cells.

Towards Antimonene and 2D Antimony Telluride through Electrochemical Exfoliation

“…The Raman spectra obtained for Sb and Sb 2 Te 3 are presented in Figure A,B. In the Raman spectrum of the Sb bulk crystal (Figure A), two bands at 117 and 153 cm −1 belonging to E g in‐plane and A 1g out‐of‐plane vibrational modes were detected . In contrast, in the spectra of the sheets, a loss in the vibrational modes in the above‐mentioned regions was observed.…”

“…In contrast with orthorhombic black phosphorus (BP), Sb does not possess true van der Waals interactions between individual layers, and is more stable under ambient conditions and still conserves high charge mobility . The Sb exfoliation to obtain antimonene is now in the spotlight because its sheets are expected to present low thermal conductance, semiconducting character and tunable bandgap from 0 to 2.28 eV, which is suitable for optoelectronic applications . Alternatively, 2D Sb 2 Te 3 , which belongs to metal transition trichalcogenides, is an attracting topological insulator with good thermoelectric performance .…”

“…Compared to Sb 2 Te 3 , with higher interlayer distances and weaker interactions, there are not many exfoliation works reported too. High‐quality sheets of Sb and Sb 2 Te 3 have been obtained by epitaxial growth, mechanical and/or liquid‐phase exfoliation methods.…”

2D Elemental Nanomaterials Beyond Graphene

“…Wang et al . have obtained large and smooth monolayer antimonene by probe sonication of Sb crystals in 2‐butanol which shows bandgap in the 0.80 eV–1.44 eV range . The antimonene sheets exhibit a remarkable hole extraction and current enhancement of ∼30% when used as a hole transport layer in a perovskite solar cell.…”

“…Apart from these applications, phosphorene and antimonnene have shown to be useful in photocatalytic carbon reduction, photothermal therapy, sensing, and solar cells …”