Dual-emissive polyaniline derived lotus-pod nano-hybrids for ultrasensitive and highly selective fluorescent recognition towards aniline

Abstract

Carbon quantum dots (CQDs) with superior sensitivity, stability and molecular recognition capability are highly desirable for sensing applications in complex environments. Herein, a new strategy to fabricate confined CQDs within PANI-derived polymer dots is designed, based on solvothermal treatment of polyaniline (PANI) and 2,3-diaminonaphthalene (2,3-DAN) using N,N-dimethylformamide as the solvent. The obtained hybrids demonstrates a unique stable “lotus-pod” structure, of which PANI-derived polymer dots functions as the pod room to confine the in situ grown CQDs. The hybrid exhibits dual-emission (blue-orange), and the existence of quinoid moieties in CQDs enables ultrasensitive fluorescent recognition of aniline with a detection limit of 12.46 pM. Its selectivity towards aniline is also outstanding in comparison of other aromatic interferents with similar structures and functional groups. The sensing mechanism could be owing to the interaction between the quinoid nitrogen and aniline molecule, resulting in fluorescence quenching. This work provides a novel design strategy to construct well-confined CQDs embedded in polymer dots with excellent sensing ability for promising fluorescent sensing applications, especially under complex conditions.