Amplified Fluorescent Conjugated Polymers as Sensors

To summarize, absorption of a photon by a conjugated polymer creates an exciton that can then sample many potential binding sites within its lifetime. Emission from the excited state is observed only if there is no bound analyte encountered by the migrating exciton. If the analyte is encountered there is quenching of the emission, and it is this amplified dimunition in emission intensity that serves as an indication (signal transduction) that the analyte is present. 

The signal transduction is obviously a very important aspect of the chemosensing scheme. Even if one exciton could sample an almost infinite number of binding sites, that would be of no benefit if the analyte was not able to alter its fluorescence. In other words, in order for there to be ampHfication, a signal must be present that can be amplified. There are several mechanisms by which signal 

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