Synthesis and characterization of diamine intercalation compounds of SnS2 single crystals

Single crystals of SnS2 were intercalated with ethylenediamine (en) and pro pylenediamine (pn) by direct reaction, The resulting novel compounds were e xamined by different techniques including XRD, XPS, a,c, impedance, TG, and TPD measurements. The observed lattice expansion for both compounds, ca, 3 .9 Angstrom, is consistent with the location of the amine molecules at van der Waals gaps, with monolayers in the alkyl chain parallel to the sulfur l ayers. XPS data reveal that these complexes easily absorb moisture that bin ds strongly to sulfur to give hydrogen sulfide traces that were detected up on thermal deintercalation above 473 K, However, the charge transferred fro m the guest to the host is too small to be detected by this photoelectron t echnique. The en intercalate preserves the semiconductor behavior of the pr istine compound, SnS2, but with two significant differences, viz, lower con ductivity at low temperatures and an increased activation energy. These dif ferences are ascribed to increased incoherent scattering of electrons resul ting from the guest atoms acting as impurities and also to the lattice defe cts formed upon intercalation. (C) 2000 Academic Press.