In this paper, a photoanode of compact TiO2 film with a small specific surface area has been developed to discuss the effects of interlayer in the dye/modification material alternating assembly structure. The compact film photoanode could avoid the complexity and various influence factors of porous film as light scattering and different diffusion rates of electrolyte in the pores. It is beneficial to discuss the effects of alternating assembly structure. From the discussion based on compact TiO2 film, it was indicated that the suitable material used for the interlayer of alternating assembly structure should show relatively strong alkalinity and higher energy level than the Lowest Unoccupied Molecular Orbital (LUMO) of dye molecules. The former is easier for the absorption of a second layer of dyes, and the latter ensured the generated electrons of the second layer of dye can inject into the conduction band of TiO2. Using the obtained suitable material as interlayer of alternating assembly structure enhanced the conversion efficiency of DSCs remarkably. (c) 2014 Elsevier Ltd. All rights reserved.