Nano ZnO, Cu-doped ZnO, and Ag-doped ZnO assisted generation of light from imidazole

•ZnO surface enhances π electron delocalisation, lowers HOMO–LUMO energies due to adsorption.•Energy gap of MNDI-Cu–ZnO lowers compared to those of pristine ZnO and thus red shift.•Energy gap of MNDI-Ag–ZnO larger compared to that with ZnO and thus blue shift.•Shortening of decay time of MNDI indicates charge transfer from MNDI to nanocrystals.•∆Get −1.23 eV indicates thermodynamic feasibility of electron transfer process.

A sensitive 2-(4-methoxyphenyl)-1-(naphthalene-1-yl)-4,5-diphenyl-1H-imidazole (MNDI) fluorescent sensor for nanoparticulate ZnO has been designed and synthesized. The nanocrystalline ZnO, Cu-doped ZnO, and Ag-doped ZnO have been synthesised by sol–gel method and characterized by powder X-ray diffraction, scanning electron microscopy(SEM), UV–vis diffuse reflectance, photoluminescence and life time spectral studies. All the synthesized nanoparticles display violet emission due to charge carrier-recombination. The synthesized sensor emission is enhanced by nanocrystalline pristine ZnO but is suppressed by Cu-doped ZnO and Ag-doped ZnO nanoparticles. The suppression of fluorescence is more by copper than by silver doping.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide