Two-dimensional perovskite material, dielectric material and multi-layered capacitor including the same

A two-dimensional perovskite material, comprising

• a layered metal oxide comprising a first layer having a positive charge and a second layer having a negative charge which are laminated, a monolayer nanosheet exfoliated from the layered metal oxide, a nanosheet laminate of a plurality of the monolayer nanosheets, or a combination thereof,
• wherein the two-dimensional perovskite material comprises about 80 volume % or greater of a first phase having a two-dimensional crystal structure, based on 100 volume % of the two-dimensional perovskite material, and
• the two-dimensional perovskite material is represented by Chemical Formula 2a:
• X[A21(n−m−1)BamB′nO(3n+1)] Chemical Formula 2a
• wherein, in Chemical Formula 2a,
• X comprises H, Li, Na, K, Rb, Cs, a cationic compound, or a combination thereof,
• A21 comprises Be, Mg, Sr, Ra, Pb, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or a combination thereof,
• B′ comprises Nb, V, Ta, Ti, Zr, Hf, W, Mo, Cr, Pb, Sn, or a combination thereof,
• n≥3, and
• 0<m≤1.

A two-dimensional perovskite material, comprising

• a layered metal oxide comprising a first layer having a positive charge and a second layer having a negative charge which are laminated, a monolayer nanosheet exfoliated from the layered metal oxide, a nanosheet laminate of a plurality of the monolayer nanosheets, or a combination thereof,
• wherein the two-dimensional perovskite material comprises about 80 volume % or greater of a first phase having a two-dimensional crystal structure, based on 100 volume % of the two-dimensional perovskite material, and
• the two-dimensional perovskite material is represented by Chemical Formula 1
• X[A11(n−m−1)A12mB′nO(3n+1)] Chemical Formula 1
• wherein, in Chemical Formula 1,
• each of A11 and A12 comprises a metal element having +2 to +3 valence, each of A11 and A12 comprises Be, Mg, Sr, Ba, Ra, Pb, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or a combination thereof, and wherein A12 has a larger ion radius than A11,
• B′ comprises Nb, V, Ta, Ti, Zr, Hf, W, Mo, Cr, Pb, Sn, or a combination thereof,
• n≥3,
• m>0, and
• n−m≠1, and
• wherein X comprises a cationic compound, and the cationic compound comprises a (C1 to C16 alkyl)ammonium compound, a (C1 to C16 alkyl)amine compound, or a combination thereof.