Charge Carrier Dynamics in Cs2AgBiBr6 Double Perovskite
Davide Bartesaghi (TU Delft - ChemE/Opto-electronic Materials, Material Innovation Institute (M2i))
Adam H. Slavney (Stanford University)
M.C. Gelvez Rueda (TU Delft - ChemE/Opto-electronic Materials)
Bridget A. Connor (Stanford University)
Ferdinand C. Grozema (TU Delft - ChemE/Opto-electronic Materials)
Hemamala I. Karunadasa (Stanford University)
TJ Savenije (TU Delft - ChemE/Opto-electronic Materials)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Double perovskites, comprising two different cations, are potential nontoxic alternatives to lead halide perovskites. Here, we characterized thin films and crystals of Cs2AgBiBr6 by time-resolved microwave conductance (TRMC), which probes formation and decay of mobile charges upon pulsed irradiation. Optical excitation of films results in the formation of charges with a yield times mobility product, φΣμ > 1 cm2/Vs. On excitation of millimeter-sized crystals, the TRMC signals show, apart from a fast decay, a long-lived tail. Interestingly, this tail is dominant when exciting close to the bandgap, implying the presence of mobile charges with microsecond lifetimes. From the temperature and intensity dependence of the TRMC signals, we deduce a shallow trap state density of around 1016/cm3 in the bulk of the crystal. Despite this high concentration, trap-assisted recombination of charges in the bulk appears to be slow, which is promising for photovoltaic applications.
help_outline