Interaction of Fluorescent 2-(1-Methoxynaphthalen-4-Yl)-1-(4-Methoxyphenyl)-4, 5-Diphenyl-1H-Imidazole with Pristine Zno, Cu-Doped Zno and Ag-Doped Zno Nanoparticles

Abstract

A sensitive 2-(1-methoxynaphthalen-4-yl)-1-(4-methoxyphenyl)-4, 5-diphenyl-1H-imidazole (MNMPI) fluorescent sensor for nanoparticulates like ZnO, Cu-doped ZnO and Ag-doped ZnO has been designed and synthesized. Facile preparation of ZnO, Cu-doped ZnO and Ag-doped ZnO nanoparticles by sol-gel method using PVP K-30 as templating agents is reported and characterised by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UVVisible spectroscopy and photoluminescence spectroscopy (PL). The synthesized sensor release is enhanced by nanocrystalline pristine ZnO but is suppressed by Cu-doped ZnO and Ag-doped ZnO nanoparticles. The suppression of fluorescence is additional by copper than by silver doping. The LUMO and HOMO energy gap of MNMPI associated with Cu-doped ZnO are lowers compared to those of pristine ZnO and thus red shift compared to that with pristine ZnO. The average crystallite sizes of ZnO, Cu-doped ZnO and Ag-doped ZnO have been deduced as 32 nm, 36 nm and 26 nm and calculated surface area for ZnO, Cu-doped ZnO and Ag-doped ZnO are 30.04 m2/g, 40.66 m2/g and 29.37 m2/g respectively. The observed enhanced absorbance with the distributed semiconductor nanoparticle is due to adsorption of MNMPI on semiconductor surface. This is because of the efficient transfer of electron from the excited state of the MNMPI to the conduction band of the semiconductor nanoparticle.