Photoinduced charge transfer (CT) processes in two novel types of dye-sensitized solar cell (DSSC) photoanodes have been investigated by ultrafast transient absorption spectroscopy (UTAS) with the aim of improving device performance, especially increasing the stability of the photoanodes and the power conversion efficiency (PCE) of solar cells. In the first case, photoanode stability was increased by covalent attachment of dye molecules to TiO2 nanoparticles (NPs) through molecular linkers, while the PCE was improved by selection of efficient linkers, optimization of the dye monolayer, and modification by metal (gold) NPs. In the second experiment, the band edge in DSSCs was tailored using hybrid structures consisting of different semiconductor materials, e.g., SnO2 nanowire (NW) matrix coated with TiO2 NPs. The time scale of the electron injection process in different materials has been measured by UTAS with time resolution of ~30 fs, which unravels the mechanisms that lead to different conversion efficiencies. UTAS results show that the electron injection process is slowed by covalent attachment but can be recovered by gold-NP-modification. The hybrid-structure photoanodes also demonstrate different CT dynamics. The spectral results and transient decay dynamics observed in the UTAS measurements can be used to guide the design and development of new types of DSSCs with higher efficiency and better stability.

Spectroscopic investigation of photoinduced charge transfer processes in dye sensitized solar cell materials

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.