DIRECTIONAL SENSITIZATION OF ZnO NANORODS BY TiOPc SUPERSONIC BEAM DEPOSITION

The ability to control the formation of hybrid structures at the nanoscale is crucial to determine specific properties and unique characteristics of the nano material. With this aim, we selective functionalize ZnO nanostructures, with organic oligomers, using Supersonic Molecular Beam Deposition (SuMBD), applying the directional properties of the seeded supersonic beams to the growth. In recent years SuMBD has been successfully used as a high controlled growth technique for organic oligomer thin films [1], with unique properties in structural and morphological order [2] and consequently improved performances in devices applications [3]. Based on the supersonic expansion of a seeded carrier gas, SuMBD present properties of high kinetic energy of the molecules and highly focused and directional beams. We applied SuMBD to ZnO nanorods [4], which present interesting advantages. First of all, ZnO nanorods present a continuous crystalline structure, which could be grown on a conductive transparent metal oxide (TCO) made ZnO doped with Aluminium (AZO) deposited directly on glass [5]. In such a way, the structural homogeneity and crystalline properties are maintained all over the NR length, allowing a continuous path for the electrons in the material. The selective functionalization with Titanyl Phthalocyianine by SuMBD on each single nanorod has been achieved. Using the directional properties of the beam, a selective growth, only on one specific side of the nanorod, has been realized. We characterized the morphological and structural properties of the nanohybrids using HR TEM, and local chemical analysis. The optical characterization using photoluminescence have been performed. The directional selective functionalization of ZnO nanorods with phthalocyanine molecules could be useful in many applications, for example in DSSC to improve solar radiation absorption, using different molecules on different sides of the nanorods.