title: Photoconductivity of CdTe Nanocrystal-Based Thin Films: Te(2-) Ligands Lead To Charge Carrier Diffusion Lengths Over 2 μm.
abstract: We report on photoconductivity of films of CdTe nanocrystals (NCs) using time-resolved microwave photoconductivity (TRMC). Spherical and tetrapodal CdTe NCs with tunable size-dependent properties are studied as a function of surface ligand (including inorganic molecular chalcogenide species) and annealing temperature. Relatively high carrier mobility is measured for films of sintered tetrapod NCs (4 cm(2)/(V s)). Our TRMC findings show that Te(2-) capped CdTe NCs show a marked improvement in carrier mobility (11 cm(2)/(V s)), indicating that NC surface termination can be altered to play a crucial role in charge-carrier mobility even after the NC solids are sintered into bulk films.
authors.affiliation: National Renewable Energy Laboratory , Golden, Colorado 80401, United States.|Department of Physics, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Crisp
authors.affiliation: National Renewable Energy Laboratory , Golden, Colorado 80401, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Callahan
authors.affiliation: Renewable and Sustainable Energy Institute, University of Colorado at Boulder , Boulder, Colorado 80309, United States.
authors.forename: Obadiah G
authors.initials: OG
authors.lastname: Reid
authors.affiliation: Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Dmitriy S
authors.initials: DS
authors.lastname: Dolzhnikov
authors.affiliation: Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Talapin
authors.affiliation: National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Garry
authors.initials: G
authors.lastname: Rumbles
authors.affiliation: National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Luther
authors.affiliation: National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Nikos
authors.initials: N
authors.lastname: Kopidakis
keywords: CdTe; nanocrystal; photoconductivity