The control of the deposition of metals on the surface of conjugated polymers determined the electronic properties of the electrical contacts. X ray photoelectron spectroscopy (XPS) and ultraviolet photon spectroscopy (UPS) was used to study the influence of an intermediate layer of barium atoms on the chemical effects that occured during the deposition of aluminium atoms of substituted poly(p-phenylvinylene) polymers. The thin films were prepared on gold substrates for spectroscopy by spin coating techniques. The diffusion of the aluminium atoms occured when the side grops were bulky and therby resulted in porous polymer films.