Photocatalytic water splitting is
a promising technology to solve the energy crisis and provide renewable
and clean energies. Recently, although numerous 2D materials have
been proposed as the photocatalytic candidates, the strategies to
effectively modulate photocatalytic reactions and conversion efficiency
are still lacking. Herein, based on first-principles calculations,
we show that the photocatalytic activities and energy conversion efficiency
can be well tuned by ferroelectric–paraelectric phase transition
of a AgBiP2Se6 monolayer. It is found that the
AgBiP2Se6 monolayer has a higher potential and
driving forces of photogenerated holes for water oxidation in the
ferroelectric phase, but higher corresponding values of photogenerated
electrons for the hydrogen reduction reaction in the paraelectric
phase. Besides, the solar-to-hydrogen energy conversion efficiency
is also tunable with the phase transition; it is up to 10.04% at the
ferroelectric phase due to the better carrier utilization, but only
6.66% at the paraelectric phase. Moreover, the exciton binding energy
is always smaller in the paraelectric state than that in the ferroelectric
state, indicating that the ferroelectric switch could also make a
directional adjustment to the photoexcited carrier separation. Our
theoretical investigation not only reveals the importance of ferroelectric
polarization on water splitting, but also opens an avenue to modify
the photocatalytic properties of 2D ferroelectric materials via a
ferroelectric switch.
The recent emergence of two-dimensional (2D) materials with intrinsic long-range magnetic order opens the avenue of fundamental physics studies and the spintronics application; however, the mechanism of interlayer magnetic coupling and the feasible way to control magnetic states are yet to be fully investigated. In the present study, from first-principle calculations, we studied the interlayer magnetic coupling of 2D CrI 3 /CrGeTe 3 heterostructures and revealed the stacking-dependent magnetic states. It is found that AB and AB 1 stacking are prefer ferromagnetic interlayer coupling, while the other two stacked configurations are in the ferrimagnetic state. The underlying mechanism has contributed to the competition between nearest-neighbor (NN) and second-nearest-neighbor (SNN) Cr−Cr atoms interaction between layers. Meanwhile, it is also found that the electronic properties are stacking dependent, while the band edge states are separated to the different layers. The magnetic and electronic states can be effectively tuned by the external strain. Based on these findings, the magnetic domain devices are proposed in the twisted magnetic heterostructures with the domain size and interlayer coupling being controlled by the rotation angle. Our study thus provides an approach to achieve the controllable magnetic/ electronic properties which is not only important for fundamental research but also useful for the practical applications in spintronics.
As a material generating increasing interest, boron nanosheets have been reviewed from the perspective of their synthesis, properties, application and possible research directions.
The recent emerged two‐dimensional (2D) ferroelectrics have attracted tremendous research interests due to their promising application in nonvolatile electronics devices. The reversible electric polarization of ferroelectrics from the off‐centered positive and negative surfaces can effectively lift the band states near Fermi level and modulate the charge distribution, which therefore play important roles for the controllable electronic/magnetic properties and chemical reactions. Here, based on the latest revealed 2D ferroelectrics, we reviewed the research progress of ferroelectric controlled physical properties and chemical reactions, including the effects of reversible polarization on magnetic and electronic behaviors, polarization dependent photocatalytic water splitting and gas adsorptions. The associated applications in electronics, sensors and energy conversion are also discussed. At last, the possible research directions of 2D ferroelectrics have also been proposed. The review is expected to inspire the research interests of 2D ferroelectrics in the practical applications.
This article is categorized under:
Structure and Mechanism > Computational Materials Science
Electronic Structure Theory > Density Functional Theory
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