title: Site-Selective Passivation of Defects in NiO Solar Photocathodes by Targeted Atomic Deposition.
abstract: For nanomaterials, surface chemistry can dictate fundamental material properties, including charge-carrier lifetimes, doping levels, and electrical mobilities. In devices, surface defects are usually the key limiting factor for performance, particularly in solar-energy applications. Here, we develop a strategy to uniformly and selectively passivate defect sites in semiconductor nanomaterials using a vapor-phase process termed targeted atomic deposition (TAD). Because defects often consist of atomic vacancies and dangling bonds with heightened reactivity, we observe-for the widely used p-type cathode nickel oxide-that a volatile precursor such as trimethylaluminum can undergo a kinetically limited selective reaction with these sites. The TAD process eliminates all measurable defects in NiO, leading to a nearly 3-fold improvement in the performance of dye-sensitized solar cells. Our results suggest that TAD could be implemented with a range of vapor-phase precursors and be developed into a general strategy to passivate defects in zero-, one-, and two-dimensional nanomaterials.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Cory J
authors.initials: CJ
authors.lastname: Flynn
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: McCullough
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: EunBi
authors.initials: E
authors.lastname: Oh
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Lesheng
authors.initials: L
authors.lastname: Li
authors.affiliation: Renewable and Sustainable Energy Institute and Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0027, United States.
authors.forename: Candy C
authors.initials: CC
authors.lastname: Mercado
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Byron H
authors.initials: BH
authors.lastname: Farnum
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Wentao
authors.initials: W
authors.lastname: Li
authors.affiliation: Chapel Hill Analytical and Nanofabrication Laboratory (CHANL), Department of Applied Physical Sciences, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3216, United States.
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Donley
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: You
authors.affiliation: Renewable and Sustainable Energy Institute and Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0027, United States.|National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Nozik
authors.affiliation: Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: McBride
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Meyer
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kanai
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: James F
authors.initials: JF
authors.lastname: Cahoon
keywords: DFT+U calculations; atomic layer deposition; dye-sensitized solar cell; nickel oxide; p-type metal oxide