Atomic Layer Engineering of High-κ Ferroelectricity in 2D Perovskites

Abstract

Complex perovskite oxides offer tremendous potential for controlling their rich variety of electronic properties, including high-T superconductivity, high-κ ferroelectricity, and quantum magnetism. Atomic-scale control of these intriguing properties in ultrathin perovskites is an important challenge for exploring new physics and device functionality at atomic dimensions. Here, we demonstrate atomic-scale engineering of dielectric responses using two-dimensional (2D) homologous perovskite nanosheets (CaNaNbO; m = 3-6). In this homologous 2D material, the thickness of the perovskite layers can be incrementally controlled by changing m, and such atomic layer engineering enhances the high-κ dielectric response and local ferroelectric instability. The end member (m = 6) attains a high dielectric constant of ∼470, which is the highest among all known dielectrics in the ultrathin region (<10 nm). These results provide a new strategy for achieving high-κ ferroelectrics for use in ultrascaled high-density capacitors and post-graphene technology.

2D Superlattices for Efficient Energy Storage and Conversion

“…)‐intercalated form, which is then swollen and delaminated into unilamellar nanosheets in formamide (Figure c) . Moreover, the composition, thickness, and lateral size of the obtained unilamellar nanosheets can be rationally designed and precisely controlled.…”

Photocatalytic activity of 2D nanosheets of ferroelectric Dion–Jacobson compounds

“…However, reports on successful exfoliation of polar/ferroelectric layered perovskites are scarce. Moreover, the few papers [14][15][16] that reported exfoliated nanosheets from polar parent phases, such as SrBi 2 Ta 2 O 9 and KCa 2 Na 2 Nb 5 O 16 (0.2 C m À2 ), all used complex multi-step chemical exfoliation routes like those used above. There is hence a need for a simple and scalable exfoliation method to prepare polar perovskite nanosheets.…”

Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis of Nano-LaCrO3

“…Perovskite compounds, ABO 3 (where A = cation of alkali, alkaline earth, or lanthanide metal and B = cation of transition metal), have unique chemical and physical properties such as oxidative, magnetic, conductive, refractive, luminescent, and catalytic. With such interesting and valuable characteristics, these compounds have been utilized tremendously in electronic devices as a tuner of the dielectric/ferroelectric responses [7] and an overcomer inefficiency on photovoltaics and other optoelectronic devices [8], sensors as a hydrazine detector [9] and ozone sensing property [10], magnetisms as a huge magnetoresistance [11] and a magnetoelectric response [12], photoluminescences as a highly photoluminescent thin film [13] and a light-emitting material [14], catalysts as CO2/H2 converter into alcohol [15] and pollutant decomposer [16], solid oxide fuel cells as a self-anode in the next power generator [17] and a good performance cathode [18], and photocatalysts as a photo-oxidator of benzylic alcohol [19] and a decomposer of dyes [20].…”