Preparation And Properties Of Rarth Element Doped Zinc Oxide Photoluminescence Materials

White LED has become a hot topic in the research of luminescent materials because of its advantages such as high luminance,long life,wide application range,energy saving and environmental protection.Among many semiconductor materials,zinc oxide(ZnO)exhibits excellent photoluminescence(PL)properties,including near-edge ultraviolet luminescence and deep level visible emission.However,ZnO only have blue,yellow and green light emition,but the lack of red light emission makes it impossible to prepare high-quality white light emitting devices base on ZnO semiconductor materials.Rare earth ion-doped wide band gap semiconductor materials which is a common method to solve such problems,especially europium ions(Eu³⁺)doped ZnO can achieve single-component white light emission.Moreover,ZnO has the wide band gap(3.37 e V),high exciton binding energy and strong absorption in the ultraviolet region,which is beneficial for rare earth element doping.In this paper,europium-doped zinc oxide(Eu³⁺:ZnO)was synthesized by hydrothermal method.Europium and terbium co-doped zinc oxide(Eu/Tb:ZnO)was synthesized by co-precipitation method.The main research contents and conclusions are as follows:(1)The effect of annealing atmosphere on the photoluminescence performance of Eu³⁺doped ZnO was studied.The luminescence mechanism and the energy transfer mechanism between Eu³⁺and ZnO were discussed.The experimental results show that Eu³⁺ion can change the morphology of ZnO and reduce its band gap.The inherent defects in the ZnO host annealed in N₂atmosphere can effectively assist the energy transfer from the ZnO host to Eu³⁺ions,thereby enhancing the intrinsic red light emission of Eu³⁺ions.The most interesting thing is that ZnO:Eu³⁺annealed in N₂atmosphere simultaneously obtained blue light(446 nm),green light(525 nm)and strong red light(618 nm).(2)The effect of surfactants on the photoluminescence properties of Eu³⁺:ZnO was studied.It was found that surfactants can change the morphology of ZnO:Eu and adjust the band gap width.Monoethanolamine(MEA)as a surfactant is more conducive to the doping of Eu³⁺ions.It is worth noting that using MEA as a surfactant will obtain strong UV emission(389 nm)while obtaining blue(448 nm),green(506 nm)and red(618 nm)emission.(3)The effect of p H on the photoluminescence of Eu/Tb:ZnO during the synthesis was studied.Experimental results show that alkaline conditions control the nucleation growth of Eu³⁺/Tb³⁺co-doped ZnO.Studies have shown that alkaline conditions are more conducive to doping Eu³⁺and Tb³⁺ions into the ZnO lattice,enhancing the UV emission(385 nm)and visible emission(400 nm-600 nm)of ZnO,and reducing surface defects of ZnO.