title: (Ga₁-xZnx)(N₁-xOx) nanocrystals: visible absorbers with tunable composition and absorption spectra.
abstract: Bulk oxy(nitride) (Ga(1-x)Zn(x))(N(1-x)O(x)) is a promising photocatalyst for water splitting under visible illumination. To realize its solar harvesting potential, it is desirable to minimize its band gap through synthetic control of the value of x. Furthermore, improved photochemical quantum yields may be achievable with nanocrystalline forms of this material. We report the synthesis, structural, and optical characterization of nanocrystals of (Ga(1-x)Zn(x))(N(1-x)O(x)) with the values of x tunable from 0.30 to 0.87. Band gaps decreased from 2.7 to 2.2 eV over this composition range, which corresponded to a 260% increase in the fraction of solar photons that could be absorbed by the material. We achieved nanoscale morphology and compositional control by employing mixtures of ZnGa(2)O(4) and ZnO nanocrystals as synthetic precursors that could be converted to (Ga(1-x)Zn(x))(N(1-x)O(x)) under NH(3). The high quality of the resulting nanocrystals is encouraging for achieving photochemical water-splitting rates that are competitive with internal carrier recombination pathways.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.
authors.forename: Kyureon
authors.initials: K
authors.lastname: Lee
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Tienes
authors.forename: Molly B
authors.initials: MB
authors.lastname: Wilker
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Schnitzenbaumer
authors.forename: Gordana
authors.initials: G
authors.lastname: Dukovic
mesh_terms: D000042:Absorption; D002384:Catalysis; D005708:Gallium / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D010316:Particle Size; D012542:Scattering, Radiation
chemical_list: D005708:Gallium