Exploring the sensing properties of pH-sensitive carbazole-based AIE emitters and their applications in paper strip sensing

A novel carbazole-coupled phenanthridine molecule with an intense blue emissive fluorescence was produced through a two-step synthesis of 5-(4-(9<i>H</i>-carbazol-9-yl)phenyl)-7,8,13,14-tetrahydrodibenzo[<i>a</i>,<i>i</i>]phenanthridine (DSPH). This blue probe shows a good thermal and electrochemical stability. It has been used for sensing trifluoracetic acid (TFA) with a limit of detection (LoD) value of 198 pM. The probe tends to show aggregation induced emission (AIE) characteristics. Additionally, the experimental data were supported by DFT analysis.