AIE-active phenothiazine based Schiff-base for the selective sensing of the explosive picric acid in real water samples and paper-based device

•Di-Phenothiazine based Schiff base (DPTZ-SB) was synthesized using facile methods.•DPTZ-SB showed AIEE properties with a 9.4-fold increase in fluorescence intensity for 10:90 DMF/water mixture.•A novel fluorescent paper sensor was developed based on DPTZ-SB.•The paper sensor is stable, recyclable, and cost-effective.•The DPTZ-SB recognized PA with a limit of detection of 0.2 ppb and 0.04 ppb in solution and paper sensor, respectively.