Band bending effect induced non-enzymatic highly sensitive glucose sensing in ZnO nanoparticles

Abstract We report band bending effect assist the enhancement of green fluorescence in ZnO nanoparticles surrounded by glucose molecules. Optical absorption measurements show free exciton absorption of ZnO around 377 nm and consistent decrease in absorption intensity while adding glucose. Room temperature photoluminescence study under excitation at 330 nm shows very strong emission in the ultra violet (UV) and visible wavelength regions. Enhancement in green emission intensity is observed while increasing concentration of glucose from 60 to 480 nM, which is attributed for decreasing depletion layer width near the surface as a result of electrons donating by glucose. Recorded time resolved emission spectra of prepared nanoparticles in the presence and absence of glucose proves that there is no energy transfer process occurs during ZnO-glucose interaction and the enhanced green emission are due to glucose molecules adsorbed on the surface of ZnO which can be applied for non-enzymatic glucose sensing applications.