| Summary: | Single crystals of the n-type semiconducting tin dichalcogenides SnS2-xSex (x = 0, 0.3, 0.5, 1.3, 1.85, 2), which have a two-dimensional layered structure, have been intercalated with cobaltocene to give the series of compounds SnS2-xSex(CoCp2)0.33, where Cp = η5-C5H5. Photoelectron spectroscopy has been employed to investigate the electronic changes upon intercalation, especially the electron transfer from the guest to the host. X-ray photoelectron spectroscopy (XPS) has revealed mixed oxidation states for both tin [Sn(II), Sn(IV)] and cobalt [Co(I), Co(II), Co(III)]. Of the three cobalt species observed by XPS, two have been unambiguously identified as CoCp2 and [COCp2]+, whereas the third cobalt species has only been tentatively assigned to a Co(η5-C5H5(η4-C 5H5R) complex, in which cobalt is formally in the oxidation state Co(I). Ultraviolet photoelectron spectroscopy (UVPES) shows that the intercalates are either semiconducting (x = 0, 0.3, 0.5, 1.3) or metallic (x = 1.85, 2), whereas all the hosts are n-type semiconductors. An impurity-band model is presented as a possible qualitative explanation for this transition through the series. © 1990 American Chemical Society.
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