Optical Fingerprints of Polynuclear Complexes in Lead-Halide Perovskite Precursor Solutions

Abstract

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 [PbI${}_{2+n}$]${}^{n-}$ 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 PbI${}_2$(DMSO)${}_4$, Pb${}_2$I${}_4$(DMSO)${}_6$, and Pb${}_3$I${}_6$(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.

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Cited by in corpus (2)

• Formation of lead halide perovskite precursors in solution: Insight from electronic-structure theory
• First-principles analysis of the optical properties of lead halide perovskite solution precursors