Optimization of UV emission intensity of ZnO nanoparticles by changing the excitation wavelength

Zinc oxide (ZnO) nanoparticles were prepared by using the sol–gel method with polyvinyl alcohol as surfactant. These ZnO nanoparticles exhibited excitation wavelength dependent photoluminescence (PL). PL spectra of ZnO were composed of different emission peaks at 384, 398, 418, 434, 467 and 492 nm depending on excitation wavelengths used. The maximum UV emission intensity was obtained when the excitation wavelength was chosen from the photoluminescence excitation (PLE) spectrum. The excitation wavelength selected from PLE is 353 nm; at this, there is more than 23 times enhancement in the UV emission intensity compared to 340 nm. At 370 nm excitation wavelength, UV emission at 398 nm was quenched completely.

► ZnO nanoparticles exhibited excitation wavelength (EW) dependent photoluminescence (PL).
► More than 23 times enhancement in the UV emission was achieved only by changing the EW.
► ZnO can be excited most efficiently at the EW chosen from the PLE spectrum.