Thin nanoporous TiO2 layers, deposited by dc reactive sputtering, have been functionalized with a novel unsymmetrical Zn(II) phthalocyanine (ZnPc-II) bearing a push–pull system, properly designed for application in dye sensitized solar cells. The anchoring process has been studied by combining visible absorption (vis), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) in order to investigate the molecular assembly during the early stage of the sensitizing process. The vis and XPS measurements indicate that the ZnPc-II surface density (dsurf, molecules/cm2) and its binding geometry are strongly affected by the concentration of the grafting solutions. It has been observed that the ZnPc-II surface density monotonically increases by increasing the solution concentration up to a saturation of dsurf ∼ 1.0 × 1013 molecules/cm2. Angle resolved XPS analyses indicate that at low molecular …