C 2012 American Chemical Society Hole Transport Materials with Low Glass Transition Temperatures and High Solubility for Application in Solid-State Dye-Sensitized Solar Cells

ye-sensitized solar cells (DSSCs) have become a promising alterna-tive photovoltaic technology to con-ventional solar cells since the original report in 1991 by O'Regan and Gratzel.1 In DSSCs, incoming light is absorbed by a sensitizing dye that is chemically attached to an n-type nanocrystalline titania framework. Upon light excitation, dye molecules inject elec-trons into the conduction bandof the titania network. This is followed by dye regenera-tion and subsequent hole transport through the hole transport materials (HTM) to the respective electrode. The highest per-forming DSSCs to date utilize a liquid-base