Dynamical Interconversion between Excitons and Geminate Charge Pairs in Two-Dimensional Perovskite Layers Described by the Onsager-Braun Model.
Mohammed, Omar F.
Gartstein, Yuri N.
Malko, Anton V.
KAUST DepartmentChemical Science Program
Functional Nanomaterials Lab (FuNL)
KAUST Catalysis Center (KCC)
KAUST Solar Center (KSC)
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Ultrafast Laser Spectroscopy and Four-dimensional Electron Imaging Research Group
Online Publication Date2020-01-20
Print Publication Date2020-02-06
Embargo End Date2021-01-21
Permanent link to this recordhttp://hdl.handle.net/10754/661347
MetadataShow full item record
AbstractTime-resolved photoluminescence (PL) and femtosecond transient absorption (TA) spectroscopy are employed to study the photoexcitation dynamics in a highly emissive two-dimensional perovskite compound (en)4Pb2Br9·3Br with the ethylene diammonium (en) spacer. We find that while the PL kinetics is substantially T-dependent over the whole range of studied temperatures T ∼ 77-350 K, the PL quantum yield remains remarkably nearly T-independent up to T ∼ 280-290 K, appreciably decreasing only at higher temperatures. Considerable differences are also revealed between the TA spectra and the responses to the excitation power at low and at room temperatures. Numerical solutions of Onsager-Braun-type kinetic-diffusion equations illustrate that the salient features of the experimental observations are consistent with the picture of a T-dependent dynamic interplay between tightly bound emissive excitons and larger-size, loosely bound, nonemissive geminate charge pairs arising already at earlier relaxation times. The geminate pairs play the role of
CitationMondal, N., Naphade, R., Zhou, X., Zheng, Y., Lee, K., Gereige, I., … Malko, A. V. (2020). Dynamical Interconversion between Excitons and Geminate Charge Pairs in Two-Dimensional Perovskite Layers Described by the Onsager–Braun Model. The Journal of Physical Chemistry Letters, 1112–1119. doi:10.1021/acs.jpclett.9b03709
SponsorsThe work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award No. DE-SC0010697.
PublisherAmerican Chemical Society (ACS)