title: Dioxo-Fluoroalkoxide Tungsten(VI) Complexes for Growth of WOx Thin Films by Aerosol-Assisted Chemical Vapor Deposition.
abstract: The soluble bis(fluoroalkoxide) dioxo tungsten(VI) complexes WO2(OR)2(DME) [1, R = C(CF3)2CH3; 2, R = C(CF3)3] have been synthesized by alkoxide-chloride metathesis and evaluated as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WOx. The (1)H NMR and (19)F NMR spectra of 1 and 2 are consistent with an equilibrium between the dimethoxyethane (DME) complexes 1 and 2 and the solvato complexes WO2(OR)2(CD3CN)2 [1b, R = C(CF3)2CH3; 2b, R = C(CF3)3] in acetonitrile-d3 solution. Studies of the fragmentation of 1 and 2 by mass spectrometry and thermolysis resulted in observation of DME and the corresponding alcohols, with hexafluoroisobutylene also generated from 1. DFT calculations on possible decomposition mechanisms for 1 located pathways for hydrogen abstraction by a terminal oxo to form hexafluoroisobutylene, followed by dimerization of the resulting terminal hydroxide complex and dissociation of the alcohol. AACVD using 1 occurred between 100 and 550 °C and produced both substoichiometric amorphous WOx and a polycrystalline W18O49 monoclinic phase, which exhibits 1-D preferred growth in the [010] direction. The work function (4.9-5.6 eV), mean optical transmittance (39.1-91.1%), conductivity (0.4-2.3 S/cm), and surface roughness (3.4-7.9 nm) of the WOx films are suitable for charge injection layers in organic electronics.
authors.affiliation: †Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States.
authors.forename: Richard O
authors.initials: RO
authors.lastname: Bonsu
authors.affiliation: ‡Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611-6005, United States.
authors.forename: Hankook
authors.initials: H
authors.lastname: Kim
authors.affiliation: ‡Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611-6005, United States.
authors.forename: Christopher
authors.initials: C
authors.lastname: O'Donohue
authors.affiliation: §Arkema Inc., 900 First Avenue, King of Prussia, Pennsylvania 19406, United States.
authors.forename: Roman Y
authors.initials: RY
authors.lastname: Korotkov
authors.affiliation: †Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States.
authors.forename: Khalil A
authors.initials: KA
authors.lastname: Abboud
authors.affiliation: ‡Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611-6005, United States.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Anderson
authors.affiliation: †Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States.
authors.forename: Lisa
authors.initials: L
authors.lastname: McElwee-White