High-Energy Resolution X-ray Photoelectron Spectroscopy Studies of Tetracyanoquinodimethane Charge-Transfer Complexes with Copper, Nickel, and Lithium

摘要

X-ray photoelectron spectra are presented for LiTCNQ, Ni(TCNQ)2. 3H2O).CuTCNQ, and Cu(TCNQ)2(TCNQ=tetracyanoquinodimethane). The Cu(TCNQ)2 compound is shown to be of a mixed valence character: Cu+(TCNQ)(TCNQ0). The TCNQ component in all the other complexes is well described as TCNQ-. The detailed shape of the shakeup intensity observed in both C1s and N1s spectra is discussed in comparison with the trend of electrical conductivity in these compounds. We suggest that the valence orbital involved in the strong XPS shakeup intensity for TCNQ- is involved in the conductivity in the charge transfer complexes. Keywords: Copper compounds; Nickel compounds; Lithium compounds: Photoelectron spectroscopy; Charge transfer; Complexes; Conductivity; Methanes; Cyanide compounds; Reprints. (MJM)