The majority of present-day fluorescent sensors consisting of a receptor and a fluorophore unit exploit the so-called photoinduced electron transfer (PET) phenomenon.[1] In PET sensors, guest binding to the receptor module invokes the shift of a donor atom s (or site s) redox potential and reversal of its ability to quench the fluorescence of the fluorophore part, thereby resulting in a measurable change in the fluorescent signal. The generality and ...
