Molecular engineering of carbazole functionalized ruthenium dyes for efficient dye-sensitized solar cells

A new ruthenium complex, coded HMP-12, incorporating an antenna ligand composed of the sequential connection of a conjugated segment and carbazole hole-transport moiety was synthesized. This dye exhibits a lower energy metal-to-ligand charge transfer (MLCT) band centered at 536 nm with a high molar absorption coefficient of 21.43 x 103 M-1 cm-1. Nanocrystalline ZnO dye-sensitized solar cells employing HMP-12 show good conversion efficiency (4.46%). It was found that the difference in light-harvesting properties between Rut-B1, HMP-11 and HMP-12 is associated mainly with dye structure. The power conversion efficiency of solar cells based on HMP-11 is 4.11% while the Rut-B1 delivered a lower efficiency of 3.57% under the same device fabrication and measuring conditions. © 2011 Vietnam Academy of Science & Technology.