The Investigation Of Optical And Luminescence Properties Of Europium And Erbium Ions In Sodium Aluminum Tellurite Ceramics

Great attention has been focused on rare-earth ions doped materials due to their potentialapplications in developing compact solid-state lasers, optical broadband amplifiers, frequencyupconverters and visible display devices. As is well known, the phonon energy of the host isthe most important factor on the luminous efficiency. Tellurite glasses have been studiedwidely since they possess good infrared transmittance, lower phonon energy and high rare-earth solubility and dispersancy. A great deal of research has been focused on RE dopedglasses and ceramics, conversely, little investigation was carried out on the luminescenceproperties of RE doped opaque ceramics. Compared with transparent glasses, opaqueceramics are considered to be with stronger absorption, which are beneficial in achievingefficient emission of rare-earth ions. In addition, ceramics show good chemical durability,mechanical strength and corrosion resistance. Thus, rare-earth doped opaque ceramics are theimportant and excellent luminescent materials.In the rare-earth family, Eu³⁺and Er³⁺ions are rather important members and effectiveactivators, and they have abundant energy levels and many of the transitions between energylevels can emit effective light. Eu³⁺and Er³⁺ions play an important role in many luminescentmaterials, and they have great potential in the development of new optical and laser materials.Owing to the relative simplicity of energy level structure, Eu³⁺can reflect the local structurearound the RE ions in various hosts. Based on this consideration, Eu³⁺doped and Er³⁺/Yb³⁺codoped sodium-aluminum-tellurite ceramics have been prepared, Optical and luminescenceproperties of rare-earth ions in sodium-aluminum-tellurite ceramics have been studied. Theresults obtained are as follows:1.1wt%Eu³⁺-doped15%Na₂O-15%A_l2O₃-70%TeO₂（NAT）sodium-aluminum-telluriteceramics （NAT ceramics） have been fabricated and characterized. Eleven emission bandsincluding blue and green peaks have been clearly recorded, and they almost cover wholevisible spectral region under violet light radiation. The maximum phonon energy ofEu³⁺:NAT ceramics has been estimated to be⁷60cm1, which is beneficial to achieving high fluorescence efficiency of RE ions. Judd-Ofelt intensity parameters Ω2and Ω4have beenderived from the emission spectrum, and the values are2.951020and0.341020cm2,respectively. Low phonon energy and bright visible fluorescence indicate that RE doped NATceramics can promote the development of illumination, display and detection devices.2.1.08wt.%Er₂O₃and2.16wt.%Yb₂O₃codoped15%Na₂O-15%A_l2O₃-70%TeO₂sodium-aluminum-tellurite ceramics （NAT ceramics） have been fabricated and characterized.Efficient green and red upconversion luminescence and intense broad1.533m infraredfluorescence were observed under the excitation of980nm diode lasers at room temperature.The visible upconversion emission bands centered at551and668nm were confirmed thattwo-photon excitation existed in these upconversion processes. The full-width at half-maximum for1.533m fluorescence is⁵5nm, and the maximum absorption and emissioncross-sections are6.851021cm2and6.611021cm2, respectively. Efficient visibleupconversion and infrared luminescence indicate that the rare-earth ions doped ceramics arepromising materials in developing color light sources, upconversion display devices, infraredsensors and infrared radiation sources.