Seminarium "Modeling of Complex Systems"

Two-dimensional halide perovskites (2DHP) are a very intriguing class of dimensionally confined semiconductors, with interesting prospects for energy-related applications, most notably, photovoltaics and light emission.[1-2] Processed from solution-techniques, these 2D materials are obtained via incorporation of bulky organic compounds, most commonly alkyl- or small aryl-molecules, which act as spacers, intercalating between atomically thin, semiconducting, metal-halide inorganic sheets.[3] The corresponding spatial confinement of the photogenerated species imparts these materials with several novel functionalities, compared to their 3D counterparts, including excitonic emission, dielectric tuning and non-linear properties.[4] In addition, several studies are demonstrating the possibility of incorporating more and more complex spacers, like p-conjugated compounds, further widening the possibilities of tuning their electronic and optical properties.[5] In this talk, we will try to provide a broad overview of the electronic and optical properties of this intriguing class of 2D-compounds, in light of their dimensional and compositional flexibility. Starting with the most common 2DHP incorporating electronically inert short alkyl chains, we will show the impact of spin orbit coupling on the electronic band structure,[6] and we will then discuss the vibronic signatures that point out towards the formation of polarons in these materials.[7] In the effort of bridging long time-established spectroscopic studies[4] with modern ab-initio simulation techniques, we will then discuss the excitonic properties of these materials, by combining symmetry analysis with ab-initio solution of the Bethe-Salpeter Equation.[8] Finally, we will explore the chemical space of these materials, by considering the impact of the substitution of divalent metal species (Sn 2+ , Pb 2+ ) with combination of monovalent/trivalent metals (Ag 1+ , Bi 3+ ),[9] as well as theincorporation of pconjugated moieties, as spacers.[10][1] S. Sidhik, et al., Science, 377, 1425−1430 (2022).[2] C. Sun, et al., Nat. Commun. 12, 2207 (2021).[3] B. Saparov and D. Mitzi, Chem. Rev. 116, 4558 (2016).[4] C. Katan, N. Mercier and J. Even, Chem. Rev. 119, 3140 (2019).[5] Y. Gao, et al., Nat. Chem., 11, 1151, (2019).[6] C. Quarti, N. Marchal and D. Beljonne, J. Phys. Chem. Lett., 9, 3416 (2018).[7] F. Thouin, et al., Nature materials 18, 349 (2019).[8] C. Quarti, et al., Adv. Opt. Mater., 12, 2202801 (2024).[9] M. Pantaler, et al., JACS Au 2022, 2, 136 (2021).[10] F. Ledée, et al., Mater. Horiz., 2021, 8, 1547-1560 (2021)

Join Zoom Meetinghttps://uw-edu-pl.zoom.us/j/94053335972?pwd=3ag9J6kMlYvbN6yJ7wmfo0G3bsaYWW.1Meeting ID: 940 5333 5972Passcode: 220764