LAUSR

Abstract The self-assembled monolayer (SAM) on TiO 2 nanocrystal surface plays an important role in the processes of photoelectric conversion in dye sensitized solar cells (DSSCs). The SAM of dye YD2- o -C8, which was the best dye for DSSCs, has been observed by scanning tunneling microscope (STM) at molecular scale for the first time. The observation results showed that different morphologies of YD2 -o- C8 SAM can be formed with or without chenodeoxycholic acid (cheno), which determined their corresponding photovoltaic cell efficiencies. The density functional theory (DFT) calculations explored the reason that was caused by the reduced electron coupling between side-to-side dimers separated by cheno molecules.