الفهرس 
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Abstract
Bismuthene, an unique and novel kind of two-dimensional material beyond graphene, has attracted a considerable attention recently for its unique electronic and photonic properties. These unique properties render of Bismuthene as an excellent candidate for various ultrafast photonic applications, e.g., nonlinear optical limiters, optical switchers, and all-optical photonic devices. Toward this goal, we report herein an easy and quick alternative method to exfoliate a semi-metal Bi crystal to obtain few layer nanosheets in two different sizes based on electrochemical exfoliation approaches. At the different wavelengths
and intensity, the resulting nonlinear optical activity is studied. The
exfoliated materials have been well characterized using various
techniques, e.g., UV-Vis-NIR absorption, photoluminescence (PL), Xray
diffraction (XRD), atomic force microscopy (AFM), scanning
electron microscopy (SEM), FT-IR, Raman, and transmission electron
microscopy (TEM). The influence of different experimental conditions,
such as the voltage on linear/nonlinear optical properties has been well
examined. In addition, the mechanism of electrochemical cathodic
exfoliation under different applied voltage in aqueous solution has been
described. This finding suggests that the bismuthene-based reverse
saturable absorber RSA is a promising new material for broadband
ultrafast optical limiters that protect against Vis-IR ultrashort pulse
laser damage.
The unique stable bismuthene nanohybrid has received a lot
of interest because of its unusual semiconducting electronic and
optical properties. To widen the uses of bismuthene in optoelectronic
and ultrafast photonic devices, its electronic and optical characteristics
should be tuned. Herein, for the first time, an efficient surface charge
ABSTRACT
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transfer doping (SCTD) approach is applied to fine-tune the electronic
and optical characteristics of bismuthene. In this study, tetrafluorotetracyanoquinodimethane
(F4TCNQ), a prevalent p-type surface
dopant, was used. Our observations of the minority carrier lifetime
using a microwave photoconductivity decay (μ-PCD) technique shifted
to 6.5 μs demonstrated that F4TCNQ has the opportunity to boost
bismuthene’s p-type conductivity due to the charge transfer from
bismuthene to F4TCNQ. Furthermore, the optical properties indicated
that the F4TCNQ could considerably improve the optical absorption
and photoluminescence of bismuthene, indicating that F4TCNQ-doped
bismuthene might be used as a novel optical material in high-efficiency
optoelectronic devices. The thermally generated intermolecular
charge transfer effect between bismuthene and F4TCNQ resulted in
an improved optical limiting response as measured by femtosecond
z-scan measurements. Our findings suggest that SCTD is an
appropriate means for modifying the electronic and optical features of
bismuthene, expanding its potential in electronic, optoelectronic and
ultrafast photonic devices.