1 research outputs found
Tunable Length and Optical Properties of CsPbX<sub>3</sub> (X = Cl, Br, I) Nanowires with a Few Unit Cells
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 (CsPbBr<sub>3</sub>) 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<sup>+</sup> during crystallization. Therefore, the positions of the Cs<sup>+</sup> 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