Photoluminescence of ZnO nanoparticles in alumina membrane with ordered pore arrays

The photoluminescence spectra of ZnO nanoparticles in the ordered pores of alumina membranes were investigated. An assembly of ZnO nanoparticles with the porous alumina membrane was synthesized by immersing the porous alumina membrane in a mixture of zinc butanol and water at 60°C and then heating at 200°C for 4 h. The photoluminescence measurements show that the assembly has a green luminescence band with the peak position at 485 nm. Compared with the photoluminescence spectra of nanostructured bulk ZnO, the luminescence intensity of ZnO nanoparticles in the alumina membrane has an enhancement of a factor of 20. This luminescence enhancement arises from the increase in singly ionized oxygen vacancies (F+ centres) in the ZnO nanoparticles located in the pores of the porous alumina membrane.