Fate of Optical Excitons in FAPbI3 Nanocube Superlattices

Year: 2024

Authors: Milloch A., Filippi U., Franceschini P., Mor S., Pagliara S., Ferrini G., Camargo F.V.A., Cerullo G., Baranov D., Manna L., Giannetti C.

Autors Affiliation: Univ Cattolica Sacro Cuore, Dept Math & Phys, I-25133 Brescia, Italy; Univ Cattolica Sacro Cuore, ILAMP Interdisciplinary Labs Adv Mat Phys, I-25133 Brescia, Italy; Katholieke Univ Leuven, Dept Phys & Astron, B-3001 Leuven, Belgium; Italian Inst Technol IIT, I-16163 Genoa, Italy; CNR, INO Natl Inst Opt, I-25123 Brescia, Italy; Univ Brescia, Dept Informat Engn, I-25123 Brescia, Italy; CNR, IFN, I-20133 Milan, Italy; Politecn Milan, Dept Phys, I-20133 Milan, Italy; Lund Univ, Dept Chem, Div Chem Phys, SE-22100 Lund, Sweden.

Abstract: Understanding the nature of the photoexcitation and ultrafast charge dynamics pathways in organic halide perovskite nanocubes and their aggregation into superlattices is key for potential applications as tunable light emitters, photon-harvesting materials, and light-amplification systems. In this work, we apply two-dimensional coherent electronic spectroscopy (2DES) to track in real time the formation of near-infrared optical excitons and their ultrafast relaxation in CH(NH2)2PbI3 nanocube superlattices. Our results unveil that the coherent ultrafast dynamics is limited by the combination of the inherent short exciton decay time (similar or equal to 40 fs) and the dephasing due to the coupling with selective optical phonon modes at higher temperatures. On the picosecond time scale, we observe the progressive formation of long-lived localized trap states. The analysis of the temperature dependence of the excitonic intrinsic line width, as extracted by the antidiagonal components of the 2D spectra, unveils a dramatic change of the excitonic coherence time across the cubic to tetragonal structural transition. Our results offer a new way to control and enhance the ultrafast coherent dynamics of photocarrier generation in hybrid halide perovskite synthetic solids.

Journal/Review: ACS PHOTONICS

Volume: 11 (9)      Pages from: 3511  to: 3520

More Information: C.G., P.F.,A.M., and S.M. acknowledge financial support from MIUR through the PRIN 2017 (Prot. 20172H2SC4 005) and PRIN 2020 (Prot. 2020JLZ52N 003) programs and from the European Union – Next Generation EU through the MUR-PRIN2022 (Prot. 20228YCYY7) program. C.G., S.P., and G.F. acknowledge support from Universita Cattolica del Sacro Cuore through D.1, D.2.2, and D.3.1 Grants. S.M. acknowledges partial financial support through the grant Finanziamenti ponte per bandi esternifrom Universita Cattolica del Sacro Cuore. G.C. acknowledges financial support by the European Union’s NextGenerationEUProgramme with the I-PHOQS Infrastructure [IR0000016, ID D2B8D520, CUP B53C22001750006] Integrated infrastructure initiative in Photonic and Quantum Sciences
KeyWords: hybrid halide perovskites; nanocube superlattices; 2D spectroscopy; multiexcitondynamics; trapstates
DOI: 10.1021/acsphotonics.4c00105