Two-Dimensional Lead Monoxide: Facile Liquid Phase Exfoliation, Excellent Photoresponse Performance, and Theoretical Investigation

Abstract

Here, we report fabrication of two-dimensional (2D) lead monoxide (PbO) nanosheets by facile liquid phase exfoliation. The as-prepared 2D PbO nanosheets have circle and cut-circle shapes with a lateral dimension range of 200−400 nm and a thickness range of 10−15 nm and exhibit dominant β-crystals with a robust chemical stability under ambient conditions. As a building block, the 2D PbO has been developed for photoelectrochemical (PEC)-type photodetectors that exhibited excellent as well as tunable photoresponse behaviors under illuminations of ultraviolet−visible lights. The first-principles density functional theory calculations further show that the band gap (E g ) of 2D PbO can be tuned by external electric field with a significant Stark effect. Moreover, differing from most transition metal dichalcogenide (TMD) materials, the 2D PbO structure, whose lowest empty states are dominated by the lead p orbitals, is exposed, which means that orbital modification of 2D PbO is accessible. Consequently, the E g of PbO can be decreased in the KOH electrolyte by a possible Pb−OH interaction, thus, broadening its absorption range for photodetection applications. In addition, the photoresponse behavior of 2D PbO-based photodetectors has long-term stability. This work may open the way for development of 2D PbO nanomaterials with promising applications.

Temperature-stable black phosphorus field-effect transistors through effective phonon scattering suppression on atomic layer deposited aluminum nitride

“…Theoretically, the intrinsic hole mobility of the few-layer BP at room temperature can exceed 5000 cm 2 V −1 s −1 , and the intrinsic electron mobility can also reach 1000 cm 2 V −1 s −1 [32], although the field-effect mobility achieved in practical was far less than its theoretical prediction. Similar observations are also reported in other two-dimensional materials [33][34][35][36][37][38][39][40]. Currently, the understanding of these mobility degradations is that the carriers' motion is constrained in the atomic-layer thickness region, which is more easily affected by the surface condition than that of bulk materials.…”

Emerging Mono‐Elemental Bismuth Nanostructures: Controlled Synthesis and Their Versatile Applications

“…The fundamental light–matter interaction in nanomaterials can also be characterized and understood by Raman scattering. [ 144,145,157,221,222 ] It can be seen from theoretical calculations that 2D Bi nanosheets have a redshift with the decrease of Bi thickness ( Figure a), [ 223 ] similar to that of black phosphorus nanosheets, [ 224 ] tellurene, [ 225,226 ] and antimonene, [ 10,227 ] which can be attributed to the fact that the interaction between layers greatly affects the out‐of‐plane atomic motions (≈150 cm −1 ). The Raman intensity of in‐plane mode (≈120 cm −1 ) increases with the thickness, similar to the G peak of graphene in the Raman spectra.…”

Self‐Powered Photodetectors Based on 2D Materials

“…In recent years, a large number of 2D materials such as 2D h‐BN, transition metal sulfides, 2D metallic oxide, and 2D black phosphorus have also been prepared, which greatly enriched the types, properties, and applications of 2D materials . In layered 2D materials, their bulk materials form a layered structure and the layer‐to‐layer formation is combined by the van der Waals force, which makes it possible to obtain single‐layer 2D materials by a top‐down method, such as micromechanical exfoliation and liquid exfoliation . All atoms of 2D single‐layer materials are approximately aligned in one plane, which makes it possible to synthesize 2D materials by a bottom‐up method, such as chemical vapor deposition and epitaxial growth .…”