Affiliation: | 1. Department of physics, University of Konstanz, D-78464 Konstanz, Germany;2. Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, LT-10257 Lithuania;3. Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, LT-10257 Lithuania Institute of Chemical Physics, Faculty of Physics, Vilnius University, Sauletekio Av. 9, Vilnius, LT-10222 Lithuania;4. imec, Kapeldreef 75, Leuven, 3001 Belgium Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg, Leuven, 3001 Belgium |
Abstract: | Heterogeneous organic-inorganic halide perovskites possess inherent non-uniformities in bandgap that are sometimes engineered and exploited on purpose, like in quasi-2D perovskites. In these systems, charge carrier and excitation energy migration to lower-bandgap sites are key processes governing luminescence. The question, which of them dominates in particular materials and under specific experimental conditions, still remains unanswered, especially when charge carriers comprise excitons. In this study transient absorption (TA) and transient photoluminescence (PL) techniques are combined to address the excited state dynamics in quasi-2D and other heterogeneous perovskite structures in broad temperature range, from room temperature down to 15 K. The data provide clear evidence that charge carrier transfer rather than energy migration dominates in heterogeneous quasi-2D perovskite films. |