title: Overcoming Film Quality Issues for Conjugated Polymers Doped with F4TCNQ by Solution Sequential Processing: Hall Effect, Structural, and Optical Measurements.
abstract: We demonstrate that solution-sequential processing (SqP) can yield heavily doped pristine-quality films when used to infiltrate the molecular dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) into pure poly(3-hexylthiophene) (P3HT) polymer layers. Profilometry measurements show that the SqP method produces doped films with essentially the same surface roughness as pristine films, and 2-D grazing-incidence wide-angle X-ray scattering (GIWAXS) confirms that SqP preserves both the size and orientation of the pristine polymer's crystallites. Unlike traditional blend-cast F4TCNQ/P3HT doped films, our sequentially processed layers have tunable and reproducible conductivities reaching as high as 5.5 S/cm even when measured over macroscopic (>1 cm) distances. The high conductivity and superb film quality allow for meaningful Hall effect measurements, which reveal p-type conduction and carrier concentrations tunable from 10(16) to 10(20) cm(-3) and hole mobilities ranging from ∼0.003 to 0.02 cm(2) V(-1) s(-1) at room temperature over the doping levels examined.
authors.forename: D Tyler
authors.initials: DT
authors.lastname: Scholes
authors.forename: Steven A
authors.initials: SA
authors.lastname: Hawks
authors.forename: Patrick Y
authors.initials: PY
authors.lastname: Yee
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Lake Shore Cryotronics , Westerville, Ohio 43082, United States.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Lindemuth
authors.affiliation: California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Tolbert
authors.affiliation: California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Schwartz
keywords: 2D grazing-incidence wide-angle X-ray scattering; Hall effect measurements; profilometry measurements; solution-sequential processing