Symmetry-informed tight-binding modeling of disordered hybrid perovskites*

In the past decade, hybrid halide perovskites have generated tremendous interest as optoelectronic materials, particularly for photovoltaïc applications due to impressive conversion efficiency values reaching over 25% in only a few years. Their large-scale industrial application, however, depends on subsequent improvements of their stability and tunability that can be achieved in both halide solid solutions (in which I, Br and Cl anions are mixed on a disordered sublattice) and two-dimensional halide perovskites (in which charge carriers are confined within inorganic atomic layers separated by organic spacers) [1,2]. Thus, it is crucial to gain an understanding of the electronic properties and carrier transport in these systems. In this talk, I will describe how a model tight-binding Hamiltonian can be extended from the archetypal CH₃NH₃PbI₃ bulk perovskite [3-5] to mixed halide perovskites and two-dimensional perovskites using a combination of symmetry considerations and DFT calculations. This will pave the way towards a robust theoretical treatment of halide clustering effects in the former, and towards a proper description of the excitonic fine structure in the latter.

[1] V Diez-Cabanes et al., Adv. Optical Mater 2001832 (2021).

[2] S. Sidhik et al., Science 377, 1425 (2022)

[3] S. Boyer-Richard et al., J. Phys. Chem. Lett. 7, 3833 (2016)

[4] A. Marronnier et al., ACS Nano 12, 3477 (2018)

[5] Z. Wei et al., Nature Communications 10, 5342 (2019)