XPS study of stilbazolium chromophores and their intercalation compounds in the MnPS3 layered phase

XPS spectra of a series of iodide salts of stilbazolium-type cations were recorded at the N1s core level. Analysis of the spectra, supported by ab initio calculations, revealed a great sensitivity of the charge distribution on the central part of the chromophores and a strong donor-acceptor intramolecular charge transfer leading to unusually intense shake-up satellite peaks. After intercalation in the MnPS3 layered phase, the XPS spectra of the chromophores showed a perturbation of their electronic distribution, this effect being especially significant for those containing a central imine double bond. These results are consistent with previous studies concerning the formation of stilbazolium J-aggregates in the interlamellar space of the host lattice.