Effects of self-assembled multilayers on the evolution of surface physical properties of indium-tin-oxide

Using layer-by-layer self-assembly technique, we have deposited multilayers of poly(diallydimethylammonium) (PDDA) and nickel phthalocyanine (NiPc) onto indium-tin-oxide (ITO) coated glass substrate. To determine how self-assembled multilayers affect charge transfer properties of conductive ITO surface, Kelvin probe and surface photovoltage measurements have been carried out. The results showed an oscillation of the surface potential as the top layer was alternated between PDDA and NiPc. The changes in surface potential of ITO induced by the growth of PDDA or NiPc monolayers are attributed to the modulation in electron affinity.