Optical Fingerprints of Polynuclear Complexes in Lead Halide Perovskite Precursor Solutions

Solvent–solute interactions in precursor solutions of lead halide perovskites (LHPs) critically impact the quality solution-processed materials, as they to formation a variety poly-iodoplumbates that act building blocks for LHPs. The [PbI2+n]n? complexes is often expected diluted solutions, while coordination occurring at high concentrations not yet well understood. In combined ab initio and experimental work, we demonstrate optical spectra quasi-one-dimensional iodoplumbate PbI2(DMSO)4, Pb2I4(DMSO)6, Pb3I6(DMSO)8 formed dimethyl sulfoxide are compatible with spectral fingerprints measured iodide concentrations. This finding suggests interpretation LHP should account polynuclear complexes.