title: Unraveling Charge Carriers Generation, Diffusion, and Recombination in Formamidinium Lead Triiodide Perovskite Polycrystalline Thin Film.
abstract: We report on studies of the formamidinium lead triiodide (FAPbI3) perovskite film using time-resolved terahertz (THz) spectroscopy (TRTS) and flash photolysis to explore charge carriers generation, migration, and recombination. The TRTS results show that upon femtosecond excitation above the absorption edge, the initial high photoconductivity (∼75 cm(2) V(-1) s(-1)) remains constant at least up to 8 ns, which corresponds to a diffusion length of 25 μm. Pumping below the absorption edge results in a mobility of 40 cm(2) V(-1) s(-1) suggesting lower mobility of charge carriers located at the bottom of the conduction band or shallow sub-bandgap states. Furthermore, analysis of the THz kinetics reveals rising components of <1 and 20 ps, reflecting dissociation of excitons having different binding energies. Flash photolysis experiments indicate that trapped charge carriers persist for milliseconds.
authors.affiliation: Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, Sin Número, 45071 Toledo, Spain.
authors.forename: Piotr
authors.initials: P
authors.lastname: Piatkowski
authors.affiliation: Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, Sin Número, 45071 Toledo, Spain.
authors.forename: Boiko
authors.initials: B
authors.lastname: Cohen
authors.affiliation: Division of Chemical Physics, Lund University , Box 124, 22100 Lund, Sweden.
authors.forename: Carlito S
authors.initials: CS
authors.lastname: Ponseca
authors.affiliation: Abengoa Research, Abengoa, Campus Palmas Altas, C/Energia Solar, 41014 Sevilla, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Salado
authors.affiliation: Abengoa Research, Abengoa, Campus Palmas Altas, C/Energia Solar, 41014 Sevilla, Spain.
authors.forename: Samrana
authors.initials: S
authors.lastname: Kazim
authors.affiliation: Abengoa Research, Abengoa, Campus Palmas Altas, C/Energia Solar, 41014 Sevilla, Spain.
authors.forename: Shahzada
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: Division of Chemical Physics, Lund University , Box 124, 22100 Lund, Sweden.
authors.forename: Villy
authors.initials: V
authors.lastname: Sundström
authors.affiliation: Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, Sin Número, 45071 Toledo, Spain.
authors.forename: Abderrazzak
authors.initials: A
authors.lastname: Douhal