Lac-extract doped polyaniline nano-ribbons as fluorescence sensor and molecular switch for detection of aqueous AsO43− and Fe3+ contaminants

•Synthesis of polyaniline nanoribbons doped with a natural dye extracted from lac insect (LAC-PANI).•Demonstration of its highly specific fluorescence sensing properties against aqueous AsO43− and Fe3+ ions.•Sharp increase and quenching of fluorescence intensity upon exposure to Fe3+ and AsO43−, respectively.•Demonstration as a NOT-AND compound molecular logic gate for simultaneous detection of Fe3+ and AsO43−.