Correlating Multichannel Charge Transfer Dynamics with Tilt Angles of Organic Donor-Acceptor Dyes Anchored on Titania

Attaching the side chains onto the electronic backbone of photosensitizing dye molecules has been a widely employed method to enhance the performance of dye-sensitized solar cells (DSCs). However, at the present time the interfacial microstructure as well as its influence on the charge transfer dynamics have not been fully comprehended, both of which underpin the phenomenological photovoltaic characteristics. In this work, we derived the tilt angles of two organic donor-acceptor dyes anchored on the surface of titania by X-ray reflectivity measurements and probed the broad time scale dynamics of charge transfer reactions in DSCs, unveiling the intrinsic roles of bulky or branched side chains attached to the conjugated segment in modulating photovoltaic behaviors.