title: Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity.
abstract: A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials such as organo-lead halide perovskites is presented. The perovskite film thickness and absorption coefficient are initially characterized by profilometry and UV-VIS absorption spectroscopy. Calibration of both laser power and cavity sensitivity is described in detail. A protocol for performing Flash-photolysis Time Resolved Microwave Conductivity (TRMC) experiments, a non-contact method of determining the conductivity of a material, is presented. A process for identifying the real and imaginary components of the complex conductivity by performing TRMC as a function of microwave frequency is given. Charge carrier dynamics are determined under different excitation regimes (including both power and wavelength). Techniques for distinguishing between direct and trap-mediated decay processes are presented and discussed. Results are modelled and interpreted with reference to a general kinetic model of photoinduced charge carriers in a semiconductor. The techniques described are applicable to a wide range of optoelectronic materials, including organic and inorganic photovoltaic materials, nanoparticles, and conducting/semiconducting thin films.
authors.affiliation: ARC Centre of Excellence in Exciton Science; School of Physics, University of New South Wales.
authors.forename: Joanna A
authors.initials: JA
authors.lastname: Guse
authors.affiliation: CSIRO, CSIRO Energy Centre.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Jones
authors.affiliation: School of Chemistry, University of New South Wales.
authors.forename: Andrew
authors.initials: A
authors.lastname: Danos
authors.affiliation: ARC Centre of Excellence in Exciton Science; School of Physics, University of New South Wales; dane.mccamey@unsw.edu.au.
authors.forename: Dane R
authors.initials: DR
authors.lastname: McCamey
mesh_terms: D007834:Lasers; D008872:Microwaves; D053758:Nanoparticles / Q000737:chemistry*; D012666:Semiconductors