title: Suppressed carrier scattering in CdS-encapsulated PbS nanocrystal films.
abstract: One of the key challenges facing the realization of functional nanocrystal devices concerns the development of techniques for depositing colloidal nanocrystals into electrically coupled nanoparticle solids. This work compares several alternative strategies for the assembly of such films using an all-optical approach to the characterization of electron transport phenomena. By measuring excited carrier lifetimes in either ligand-linked or matrix-encapsulated PbS nanocrystal films containing a tunable fraction of insulating ZnS domains, we uniquely distinguish the dynamics of charge scattering on defects from other processes of exciton dissociation. The measured times are subsequently used to estimate the diffusion length and the carrier mobility for each film type within the hopping transport regime. It is demonstrated that nanocrystal films encapsulated into semiconductor matrices exhibit a lower probability of charge scattering than that of nanocrystal solids cross-linked with either 3-mercaptopropionic acid or 1,2-ethanedithiol molecular linkers. The suppression of carrier scattering in matrix-encapsulated nanocrystal films is attributed to a relatively low density of surface defects at nanocrystal/matrix interfaces.
authors.affiliation: The Center for Photochemical Sciences, Department of Physics, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors.forename: Pavel
authors.initials: P
authors.lastname: Moroz
authors.forename: Natalia
authors.initials: N
authors.lastname: Kholmicheva
authors.forename: Bryan
authors.initials: B
authors.lastname: Mellott
authors.forename: Geethika
authors.initials: G
authors.lastname: Liyanage
authors.forename: Upendra
authors.initials: U
authors.lastname: Rijal
authors.forename: Ebin
authors.initials: E
authors.lastname: Bastola
authors.forename: Kyla
authors.initials: K
authors.lastname: Huband
authors.forename: Elena
authors.initials: E
authors.lastname: Khon
authors.forename: Keith
authors.initials: K
authors.lastname: McBride
authors.forename: Mikhail
authors.initials: M
authors.lastname: Zamkov