Characterization of Singlet Fission Following Photoexcitation of TIPS-pentacene in Solution

The Shockley-Queisser limit sets an upper bound on the efficiency of single junction solar cells of ~30%. Singlet Fission (SF) offers the potential to overcome this limitation as SF materials can yield two charge carriers for each absorbed photon. TIPS-pentacene (TIPS=6,13-bis-(triisopropylsilylethynyl)) is an extensively studied SF chromophore as it has been reported to approach a 200% triplet yield. However, the microscopic mechanism of the formation and the atomic structure of the triplet states are still largely unknown. Measuring the photoinduced transient structures will provide a much-needed test of the atomistic mechanism of SF in organic chromophores, paving the way for a rational design of SF materials in solar cell application. We propose to directly probe the molecular structure and dynamics involved in SF of TIPS-pentacene in solution with Time-Resolved X-ray Solution Scattering (TR-XSS) using the Time-Resolved Wide-Angle X-ray Scattering (TR-WAXS) setup at ID09.