Photoluminescence Properties Of Rare Earthdoped Oxide Light-converting Phosphors

In recent years, upconversion luminescence materials and quantum cutting materials have been extensively attented and researched. Upconversion materials have wide application in near infrared detection and other fields.Quantum cutting materials have wide application in lasma flat panel display,high-efficiency solar cells and other fields.The matrixes of upconversion materials and quantum cutting luminescent materials are mostly fluoride. But fluoride is unstable, which limits their practical application. In this paper, we choose Gd Ba3B9O18 as matrix. Gd Ba3B9O18 is one of a series of isomorphic borate compounds synthesized by Institute of Physics of Chinese Academy of Sciences.Its physical and chemical properties are very stable.It is a potential matrix of luminescent material.We study on the preparation and luminescent properties of several rare-earth-doped Gd Ba3B9O18 phosphors. The main contents in this work are as follows:(1)Gd Ba3B9O18:Eu3+ phosphor and Gd Ba3B9O18:Tb3+ phosphor were prepared by solid state reaction method. Their structure and morphology were characterized by X-ray diffraction and scanning electron microscopy. The results show that the samples meet the requirements of the luminescent material in terms of structure and morphology. The luminescence spectra shows that there is visible quantum cutting process in Gd Ba3B9O18:Eu3+ phosphor and Gd Ba3B9O18:Tb3+ phosphor.The Quantum efficiency of them is 127% and 146%, respectively.(2) We prepare Gd Ba3B9O18:Tb3+/Yb3+, Gd Ba3B9O18:Er3+/Yb3+, Gd Ba3B9O18:Ho3+/ Yb3+ by solid state reaction method. Their structure and morphology were characterized by X-ray diffraction and scanning electron microscopy. The luminescence spectra shows that effective down-conversion luminescence can be fiound in Gd Ba3B9O18:Tb3+,Yb3+.Effective upconversion luminescence can be fiound in Gd Ba3B9O18: Er3+, Yb3+ and Gd Ba3B9O18: Ho3+, Yb3+.(3)We explore the luminescence mechanism of the samples.In Gd Ba3B9O18:Eu3+,the energy transfer between Gd3+-Eu3+ can be achieved via two step energy transfers from Gd3+ to Eu3+ by cross relaxation and sequential transfer. The quantum cutting in Gd Ba3B9O18:Tb3+ can be achieved via energy transfer between two Tb3+ ions. Gd3+ is used as a media of energy transfer.The energy transfer in Gd Ba3B9O18:Er3+/Yb3+ and Gd Ba3B9O18:Ho3+/Yb3+ can be achieved via cross relaxation and sequential transfer.