Halogenated Antimonene: One‐Step Synthesis, Structural Simulation, Tunable Electronic and Photoresponse Property

Abstract

Surface functionalization is considered to be an effective and versatile strategy to tailor intrinsic electronic and optoelectronic properties of 2D materials. In this work, surface‐decorated few‐layer antimonene is synthesized by a one‐step electrochemical exfoliation and synchronous halogenation method in halogen‐containing an ionic liquid–based electrolyte at room temperature. The prepared halogenated antimonene nanosheets are composed of oxygen‐ and halogen‐decorated amorphous and crystalline domains. The structural reconstructions and evolutions of halogenated antimonene are further revealed by ab initio molecular dynamics simulations and first‐principles calculations. The band structures and optical properties of antimonene can be tailored after amorphization and surface functionalization, depending on the reactivity of different halogens. The photoresponse performance of the halogenated antimonene is further evaluated by photoelectrochemical measurement. Exhibiting self‐powered photoresponse behavior, their photocurrent density increases with the increases of external bias potential and light intensity. This work proposes a new idea of tuning the optoelectronic properties of 2D materials by synchronous halogenation in the facile one‐step electrochemical synthesis process. Benefiting from this facile synthesis procedure, the halogenation of antimonene may shed light on chemical functionalization of other 2D materials for electronic and optoelectronic applications.

Monocrystalline Antimonene Nanosheets via Physical Vapor Deposition

“…The bandgap was estimated using the Tauc plot (as presented in the Supporting Information in the Experimental Section) which yields an optical bandgap of 2.53 eV (shown in Figure 5a). [ 47 ] The obtained bandgap values are also in the range of values obtained with our partial density of states (PDOS) and calculated band structure for the β‐phase antimonene (shown in Figure 2 and Figure S5, Supporting Information) with predominant 5p states in valence band region. PDOS further confirms the β‐phase antimonene obtained in Figure S5 (Supporting Information) which is starkly distinct from the α‐phase antimonene which has a characteristic high energy band in its conduction band that is dominated by the 4d orbitals.…”

“…The process for obtaining the bandgap using Tauc plot is as follows. A relational expression put forth by Mott and, Davis, Tauc is used [47,53] h Ah E n 1/ g να ν ( )…”

“…The process for obtaining the bandgap using Tauc plot is as follows. A relational expression put forth by Mott and, Davis, Tauc is used [ 47,53 ] where h is the Planck's constant, ν is the frequency of vibration, α is the absorption coefficient, E g is the bandgap, and A is the proportional constant.…”

Halogen Functionalization in the 2D Material Flatland: Strategies, Properties, and Applications

“…In‐process halogenation acquires halogen ions or moieties from halogen sources precisely under the 2D material synthesis conditions; therefore, this method can facilitate the reaction steps of acquiring target‐halogenated products, improve synthesis efficiency, and avoid contamination of the product, which may be encountered in intermittent processes. This strategy includes thermal self‐condensation, [ 60–67,69 ] mechanochemical ball milling, [ 51–56,68 ] electrochemical intercalation, [ 57,58,72–76 ] and solvothermal synthesis, [ 50,70,71 ] with the aid of various halogen‐containing reagents. Wang et al.…”

Advances in photonics of recently developed Xenes

“…Buckled monolayer antimonene possesses an indirect bandgap of 2.28 eV, but it would transfer to a semimetal with the increasing layer number approaching to the bulk feature ( Figure 6B) [85]. Furthermore, antimonene can be transfer to a direct semiconductor under tensile strains, and a bandgap can be opened in few-layer semimetal antimonene after surface functionalized, making it a semiconductor with possible applications in optoelectronic devices [89]. Following theoretical prediction, the experimental synthesis of antimonene by means of mechanical exfoliation [90,91], liquid-phase exfoliation [86,92,93], van der Waals epitaxy [94,95], molecular beam epitaxy [96,97], and solution synthesis [98] was boomingly developed for their practical applications in optoelectronics [93,99], photonics [100,101,125], energy devices [102,103], and biomedicine [104][105][106].…”