title: Tunable Length and Optical Properties of CsPbX3(X = Cl, Br, I) Nanowires with a Few Unit Cells.
abstract: Perovskite nanostructures, both hybrid organo-metal and fully inorganic perovskites, have gained a lot of interest in the past few years for their intriguing optical properties in the visible region. We report on inorganic cesium lead bromide (CsPbBr3) nanowires (NWs) having quantum confined dimensions corresponding to 5 unit cells. The addition of various hydrohalic acids (HX, X = Cl, Br, I) was found to highly affect the NW length, composition, and optical properties. Hydrochloric (HCl) and hydroiodic (HI) acids mixed in the reaction solution influence the crystal structure and optical properties and shorten the NWs, while the hydrobromic acid (HBr) addition results solely in shorter NWs, without any structural change. The addition of HX increases the acidity of the reaction solution, resulting in protonation of the oleylamine ligands from oleylamine into oleyl-ammonium cations that behave similarly to Cs+during crystallization. Therefore, the positions of the Cs+at the growing surface of the NWs are taken by the oleyl-ammonium cations, thus blocking further growth in the favored direction. The emission of the NWs is tunable between ∼423-505 nm and possesses a potential in the optoelectronic field. Moreover, electrical conductivity measurements of the NWs are discussed to give a new point of view regarding the conductivity of perovskite nanostructures.
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Casali Center for Applied Chemistry, The Hebrew University of Jerusalem , Jerusalem, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Amgar
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Casali Center for Applied Chemistry, The Hebrew University of Jerusalem , Jerusalem, Israel.
authors.forename: Avigail
authors.initials: A
authors.lastname: Stern
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Casali Center for Applied Chemistry, The Hebrew University of Jerusalem , Jerusalem, Israel.
authors.forename: Dvir
authors.initials: D
authors.lastname: Rotem
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Casali Center for Applied Chemistry, The Hebrew University of Jerusalem , Jerusalem, Israel.
authors.forename: Danny
authors.initials: D
authors.lastname: Porath
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Casali Center for Applied Chemistry, The Hebrew University of Jerusalem , Jerusalem, Israel.
authors.forename: Lioz
authors.identifier: 0000-0001-6158-8520
authors.initials: L
authors.lastname: Etgar
keywords: All-inorganic perovskite; absorption; electrical conductivity; nanowires; photoluminescence; transmission electron microscopy