Few‐layer Bismuthene: Sonochemical Exfoliation, Nonlinear Optics and Applications for Ultrafast Photonics with Enhanced Stability

Abstract

As the last element in Group VA, bismuthene has garnered substantial interest for its unique electronic and mechanical properties and its enhanced stability. However, the mechanism that drives the light-bismuthene interaction remains completely unclear. Herein, a sonochemical exfoliation approach is employed to deliver a successful synthesis of few-layer bismuthene. The corresponding nonlinear optical response at the visible wavelength is investigated. The nonlinear refractive index is ß10 −6 cm 2 /W and was measured by spatial self-phase modulation. Thanks to its direct energy band-gap at 1550 nm, the saturable absorption property of bismuthene is experimentally illustrated at the telecommunication band with an optical modulation depth of ß2.03% and a saturable intensity of ß30 MW/cm 2 . The optimization of the laser parameters resulted in the generation of an ß652-femtosecond optical pulse centered at 1559.18 nm. This result indicates that the bismuthene-based saturable absorber is indeed a new and excellent material for an ultrafast saturable absorber device. Our work highlights the promise of this material in ultrafast photonics and may be considered as an important step towards bismuthene-based photonics devices (optical modulator, optical switcher, detector, etc.).

Chemistry of Layered Pnictogens: Phosphorus, Arsenic, Antimony, and Bismuth

“…Few‐layered arsenic and other pnictogens were prepared by Pumera et al. by shear force exfoliation (Figure ) and bismuth nanosheets by the sonication method . The exfoliation of antimony was achieved by improved scotch tape technique or by liquid‐phase exfoliation .…”

“…Thec hemistry of other pnictogens is very scarce.F ewlayered arsenic and other pnictogens [44] were prepared by Pumera et al by shear force exfoliation ( Figure 6) and bismuth nanosheets by the sonication method. [45] Thee xfoliation of antimony was achieved by improved scotch tape technique [46] or by liquid-phase exfoliation. [47] Antimony quantum dots were prepared by electrochemical exfoliation followed by centrifugation.…”

2D Elemental Nanomaterials Beyond Graphene

“…The few‐layer bismuthene nanosheets have been characterized by TEM and Raman spectroscopy (Figure d–f). The liquid exfoliated bismuthene exhibits nonlinear characteristics with a nonlinear refractive index of ∼10 −6 cm 2 /W . Wet‐chemical methods can also be used for the synthesis of ultrathin bismuthene nanosheets through reduction of bismuth nitrate under reflux condition .…”

Recent Advances on Black Phosphorus Based Electrocatalysts for Water‐Splitting

“…[21] In the meantime, few-layer BP (known as phosphorene) was just exfoliated from the bulk BP, [22][23][24][25] which has attracted great interests and undoubtedly become one of the hottest stars shining in the single element two-dimensional (2D) materials. [26][27][28][29][30][31][32] Since there are five electrons on 3p orbitals of P atom, within phosphorene structure, each P atom covalently bonds to three neighboring P atoms, forming a puckered orthorhombic lattice and leaving a pair of lone electrons. [19,33,34] The fascinating properties of phosphorene such as tunable layer-dependent direct bandgap, [35,36] high charge-carrier mobility and unique inplane anisotropic structure [37] have triggered intense research.…”