Spirobifluorene-Based Electropolymerized Films for Highly Sensitive and Reversible Detection of Tnp in Water

Abstract

Two novel polymer network films (TCTSp-EP and OCTSp-EP) were prepared from tetra- and octacarbazolyl-substituted spirobifluorene star-shaped molecules (TCTSp and OCTSp) by electrochemical polymerization. The monomers had the expected aggregation-induced enhanced emission (AIEE) activity and exhibited excellent emission behavior in the aggregation state. The TCTSp and OCTSp had multiple electroactive carbazole groups which enabled the formation of polymer network films by electrochemical polymerization. Compared with TCTSp, the more carbazoles in the OCTSp improved the electrical activity and increased the film thickness growth rate. The films of TCTSp-EP and OCTSp-EP can be used for the high-sensitive and selective detection of 2,4,6-trinitrophenol (TNP) in water. The calculated Stern-Volmer quenching constants indicated that OCTSp-EP was more sensitive to TNP in water than TCTSp-EP. This was due to the hyperbranched structure of OCTSp-EP which had more exciton migration channels. The mechanism of TCTSp-EP and OCTSp-EP film for the detection of TNP was because of photo-induced electron transfer (PET) and fluorescence resonance energy transfer (FRET). Both of these films had excellent cycling performance which could be used to identify TNP in natural water.

Keywords: Electropolymerized, Fluorescence Sensor, reusability, Spirobifluorene, 2, 4, 6-Trinitrophenol