Polymer-Sensitized Solar Cells Using Polythiophene Derivatives with Directly Attached Carboxylic Acid Groups

Polythiophene derivatives with carboxylic acid groups directly attached to the thiophene rings were synthesized for polymer-sensitized solar cells (PSSCs). The polymer layer densely and uniformly covering the surface of the TiO 2 particle in the photoanode of the PSSCs allows excitons to diffuse to the polymer/TiO 2 interface efficiently. The PSSCs yielded a maximum incident photon-to-current conversion efficiency of about 80% at 480 nm and the open-circuit voltage ( V OC ) values but also short-circuit current density ( J SC ) values increased with decreasing hydrolysis ratio of the polymer.