How to modulate the molecular structure to finely manipulate the sensing performance is of great significance for propelling the oriented design of the optical sensing probe. Here, by taking the optical detection toward amphetamine (AMP) as a model, a structural regulation strategy for the D-π-A probe was proposed to manipulate the reaction activity and optical response. The optimal probe was screened out from a series of D-π-A molecules with an electrophilic site owing to its faster response and more remarkable emission shift, as well as the desirable specificity. In particular, it was found that the probe reactivity induced two trade-off effects. First, it is kinetically expressed by the reaction time that greatly affects the sensitivity (emission shift), and second, it thermodynamically determines the specificity. Upon fine modulation, the optimal probe in the solid state integrated in a portable sensing chip was demonstrated with fast and visualized analysis for AMP in complicated scenarios. Overall, the proposed structure-performance correlation and the mediation on the trade-off effect would provide an in-depth insight for the oriented design of an optical sensor with a desirable sensing performance.
Keywords: D-π-A molecule; amphetamine; illicit drugs; optical sensor; trade-off.