title: Nonhydrolytic synthesis of high-quality anisotropically shaped brookite TiO2 nanocrystals.
abstract: A surfactant-assisted nonaqueous strategy, relying on high-temperature aminolysis of titanium carboxylate complexes, has been developed to access anisotropically shaped TiO2 nanocrystals selectively trapped in the metastable brookite phase. Judicious temporal manipulation of precursor supply to the reaction mixture enables systematic tuning of the nanostructure geometric features over an exceptionally wide dimensional range (30-200 nm). Such degree of control is rationalized within the frame of a self-regulated phase-changing seed-catalyzed mechanism, in which homogeneous nucleation, on one side, and heterogeneous nucleation/growth processes, on the other side, are properly balanced while switching from the anatase to the brookite structures, respectively, in a continuous unidirectional crystal development regime. The time variation of the chemical potential for the monomer species in the solution, the size dependence of thermodynamic structural stability of the involved titania polymorphs, and the reduced activation barrier for brookite nucleation onto initially formed anatase seeds play decisive roles in the crystal-phase- and shape-tailored growth of titania nanostructures by the present approach.
authors.affiliation: Scuola Superiore ISUFI, University of Salento, Distretto Tecnologico, via per Arnesano km 5, 73100 Lecce, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Buonsanti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Grillo
authors.forename: Elvio
authors.initials: E
authors.lastname: Carlino
authors.forename: Cinzia
authors.initials: C
authors.lastname: Giannini
authors.forename: Tobias
authors.initials: T
authors.lastname: Kipp
authors.forename: Roberto
authors.initials: R
authors.lastname: Cingolani
authors.forename: Pantaleo Davide
authors.initials: PD
authors.lastname: Cozzoli
mesh_terms: D016880:Anisotropy; D002264:Carboxylic Acids / Q000737:chemistry; D003460:Crystallization; D049329:Nanostructures / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D010316:Particle Size; D033362:Powder Diffraction; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D009942:Organometallic Compounds; D013501:Surface-Active Agents; C009495:titanium dioxide; D014025:Titanium