The formation of copper sulphide semiconductors inside Langmuir–Blodgett films of Cu(II) ion complexes

The fabrication of layers of copper sulphide within multilayers of copper complexes of the amphiphile 4-(10,12-pentacosadiynamido methyl pyridine, by diffusion of H2S into the multilayers, was studied by UV–VIS spectroscopy. XPS measurements revealed that copper sulphides can be synthesised which differ in stoichiometry when multilayers are used, which were built up from different subphases (CuCl2 or Cu(ClO4)2). The distinct layer pattern of the Langmuir–Blodgett (LB) films is preserved during the formation of the copper sulphide layers and the bilayer distance increases slightly by about 1.8 Å for the multilayers built up from a 5 mM CuCl2 subphase, whereas for the multilayers built up from a 5 mM Cu(ClO4)2 subphase the bilayer distance decreases a little by about 0.6 Å after the formation of copper sulphide inside these LB films. After polymerisation the multilayer structure is destroyed in the case of LB films built up from the CuCl2 subphase, whereas the layer structure is preserved during the polymerisation process in the case of multilayers built up from a 5 mM Cu(ClO4)2 subphase.