Efficient quasi-solid dye sensitized solar cells employing molten salt electrolyte

Abstract

There have been many attempts to increase the overall conversion efficiency of dye-sensitized solar cells using liquid-state electrolytes. However, this type of cells have unsolved critical problems such as leakage and evaporation of volatile organic solvents. Thus the development of more stable solid or quasi–solid state cell is of great importance. In the study reported here, we developed a novel fabrication method of dye sensitized quasi-solid solar cells using solid composite materials of LiSCN and methyl-hexyl-imidazolium iodide (MHImI) as hole transport materials to replace liquid iodide and polyiodide electrolyte which consists of volatile solvents. The device based on 6 µm thick nanocrystalline TiO 2 film absorbed by monolayer of Ru(II) terpyridyl complex photosensitizer (N719 dye), shows excellent incident photon-to-electron conversion efficiency (IPCE, ~ 75%) , large current density (11.6 mA cm -2 ), and high light-to-electric energy conversion efficiency (5.3- 6.1%) under the illumination of 100 mW cm -2 (AM 1.5).