title: Polymer/Perovskite-type nanoparticle multilayers with multielectric properties prepared from ligand addition-induced layer-by-layer assembly.
abstract: We introduce an adsorption mechanism for a layer-by-layer (LbL) assembly (i.e., a ligand addition-induced LbL assembly) and demonstrate that the (polymer/perovskite nanoparticle (NP))n nanocomposite films based on the ligand addition LbL exhibit ferroelectric and resistive switching properties. Oleic acid (OA)-stabilized BaTiO3 NPs (OA-BTO NPs) with a size of approximately 8 nm were LbL-assembled with amine-functionalized dendrimers (NH2-dendrimers) using the high affinity between NH2 moieties and Ti ions. The ferroelectric properties of the (NH2-dendrimer/OA-BTO NP)n multilayers were generated by the Ti disorder in the OA-BTO NP unit cell despite the use of sub-10 nm OA-BTO NPs (i.e., OA-BTO NPs), which are near the critical size for ferroelectric properties. Additionally, the (NH2-dendrimer/OA-BTO NP)n multilayers sandwiched between the bottom (platinum) and top (silver or tungsten) electrodes exhibited a resistive switching memory at a relatively low operating voltage below 2 V with a switching speed of approximately 100 ns and an ON/OFF current ratio of approximately 10(4). Furthermore, the ferroelectric and resistive switching properties could be further improved by controlling the bilayer number (n). We believe that our approach can provide a basis for designing and exploiting multifunctional memory electronics based on a variety of perovskite NPs with ferroelectric properties.
authors.affiliation: Department of Chemical & Biological Engineering, Korea University , Anam-dong, Seongbuk-gu, Seoul 136-713, South Korea.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Kim
authors.forename: Kyungyun
authors.initials: K
authors.lastname: Kook
authors.forename: Sun Kak
authors.initials: SK
authors.lastname: Hwang
authors.forename: Cheolmin
authors.initials: C
authors.lastname: Park
authors.forename: Jinhan
authors.initials: J
authors.lastname: Cho