Functional Interfaces

BODIPY-based donor-acceptor dyads are widely used as sensors and probes in life science. Thus, their biophysical properties are well established in solution, while their photophysical properties in cellulo, i.e., in the environment, in which the dyes are designed to function, are generally understood less. To address this issue, we present a sub-ns time-resolved transient absorption study of the excited-state dynamics of a BODIPY-perylene dyad designed as a twisted intramolecular charge transfer (TICT) probe of the local viscosity in live cells.