Fluorescence‐based logic gate for sensing of Ca2+ and F− ions using PVP crowned chrysene nanoparticles in aqueous medium

Polyvinyl pyrrolidone (PVP) crowned chrysene nanoparticles (CHYNPs) were prepared by using a reprecipitation method. Dynamic light scattering (DLS) and scanning electron microscope (SEM) studies indicate that the monodispersed spherical nanoparticles bear a negative charge on their surfaces. The bathochromic spectral shift in the UV–visible and fluorescence spectrum of CHYNPs from chrysene (CHY) in acetone solution supports the J‐ type aggregation of nanoparticles. The aggregation‐induced enhanced emission of CHYNPs at 486 and 522 nm decreases by increasing the concentration of the Ca²⁺ ion solution. It can display an ON–OFF type fluorescence response with high selectivity towards Ca²⁺ ions aqueous medium. Furthermore, the in situ generated PVP–CHYNPs–Ca²⁺ ensemble could recover the quenched fluorescence upon the addition of fluoride anions resulting in an OFF–ON type sensor. The present method has a correlation coefficient R² = 0.988 with a detection limit of 1.22 μg/mL for Ca²⁺ in the aqueous medium. The fluorescence changes of PVP crowned CHYNPs upon the addition of Ca²⁺ and F^? can be utilized as an INHIBIT logic gate at the molecular level, using Ca²⁺ and F^? chemical inputs and the fluorescence intensity signal as output.