Solvent-solute interactions in precursor solutions of lead halide perovskites (LHP) critically impact the quality of solution-processed materials, as they lead to the formation of a variety of poly-iodoplumbates that act as building blocks for LHP. The formation of [PbI2+n]n− complexes is often expected in diluted solutions while coordination occurring at high concentrations is not well understood yet. In a combined \textit{ab initio} and experimental work, we demonstrate that the optical spectra of the quasi-one-dimensional iodoplumbate complexes PbI2(DMSO)4, Pb2I4(DMSO)6, and Pb3I6(DMSO)8 formed in dimethyl sulfoxide solutions are compatible with the spectral fingerprints measured at high concentrations of lead iodide. This finding suggests that the formation of polynuclear lead-halide complexes should be accounted for in the interpretation of optical spectra of LHP precursor solutions.
@article{arxiv.2012.08440,
title = {Optical Fingerprints of Polynuclear Complexes in Lead-Halide Perovskite Precursor Solutions},
author = {Ana M. Valencia and Oleksandra Shargaieva and Richard Schier and Eva Unger and Caterina Cocchi},
journal= {arXiv preprint arXiv:2012.08440},
year = {2021}
}