Electronic transduction mechanism

This local carrier energy change results in significant OFET current changes, as shown, for example, in pentacene [17,18] and poly(hexylthiophene) [19] OFETs. While the voltage applied to most OFETs in published accounts 

---

In contrast to the information transduction mechanism based on conformational change, the information transduction may effectively be performed through the electron transfer if the integrated molecular systems are composed of electronically active molecules. 

Many chemosensors exploit electron transfer as the signal transduction mechanism. Owing to different design constraints, we distinguish among systems whose function is derived from PET as described by Fig. 6 versus those systems whose function relies on electron (or energy) transfer between discrete donor and acceptor sites. 

Interestingly, if the same titration experiment is performed in presence of any other 3d divalent cation (Mn Fe, Co, Zn ), no fluorescence quenching is observed over the entire 2-12 pH interval. In this connection, it must be noted that deprotonation of the amide groups of the dioxocyclam subunit is an especially endothermic process, which can take place only if the unfavorable heat effect is compensated by the exothermic formation of strong metal-ligand bonds. This situation occurs only with metal ions late in the 3d series, e.g., Ni and Cu , but not with cations earlier in the same series. Thus, the anthracene functionalized dioxocyclam system represents a selective fluorescent sensor for Cu" and Ni , whose signal transduction mechanism is an electron transfer process [13]. 

This article will concern itself only with devices that involve a chemical or biochemical transduction mechanism to generate the analytical information, with the processes occurring in a membrane or layer attached to the probe in such a manner that the analytical information can be accessed electronically from the outside world. This covers sensors that are for single use and for continuous monitoring because the basic chemistry and sensor configuration used are very similar for a particular application. Hence, the article does not cover techniques such as open-cell Fourier transform infrared or remote fiber spectroscopy, which can be used to sense the chemical nature of the environment without involving the use of a bona fide sensor. 

---