Study On Near Infrared Luminescence Of Er³⁺ In Silicate

Near-infrared（NIR）light is widely used in night vision,communication,detection and so on,due to its unique characteristics.Near-infrared light of 1.5μm,which is just the lowest loss of optical fiber communication,is a research focus in academia.In this paper,we use Er³⁺as the luminescent activator to study 1.5μm NIR light.We use silicate as the matrix,Mn⁴⁺,Ce³⁺and Yb³⁺as the sensitizing ions to improve the NIR luminescence of Er³⁺in several silicates,and explore the effect of the sensitizing ions on the luminescence as well as the energy transfer between Er³⁺and the sensitizing ions.The aim is to find 1.5μm near-infrared fluorescent materials that can be practically applied.The main works of the paper are:A series of new NIR luminescent materials Yb³⁺and Er³⁺co-doped Ca₃Y₂Si₃O₁₂were synthesized by high-temperature solid-phase method.The spectra of samples with doping of different Er³⁺concentrations were tested under the excitation of 980nm light,and the best luminescence intensity sample 0.4Er³⁺doped Ca₃Y₂Si₃O₁₂ was obtained.The near-infrared luminescence intensity of Er³⁺increases by 3.3 times by introducing the sensitized ion Yb³⁺into the sample Ca₃Y₂Si₃O₁₂:0.4Er³⁺.By analyzing the upconversion luminescence of Er³⁺in the matrix Ca₃Y₂Si₃O₁₂,it was found that the upconversion luminescence of Er³⁺restricts the particle populating of⁴I_13/2 of Er³⁺,which severely affects the NIR luminescence intensity.A series of novel NIR luminescent materials Mn⁴⁺and Er³⁺co-doped Sr₃Al₁₀Si O₂₀were synthesized by high temperature solid phase method.The spectra of the doped samples with different Er³⁺concentrations were tested under 455 nm light excitation,and the best luminescence intensity sample 0.09Er³⁺doped Sr₃Al₁₀Si O₂₀ was obtained.The near-infrared luminescence intensity of Er³⁺is nearly enhanced by 1 time after the introduction of the sensitized ion Mn⁴⁺into the sample Sr₃Al₁₀Si O₂₀:0.09Er³⁺.The excitation and emission spectra of a series of samples were tested,and the energy transfer mode and energy transfer path between Mn⁴⁺and Er³⁺was discussed.A series of novel NIR materials Ce³⁺and Er³⁺co-doped Ca_1.5Y_1.5Al_3.5Si_1.5O₁₂were synthesized by high-temperature solid-phase method.The spectra of the doped samples with different Er³⁺concentrations were tested under the excitation of 455 nm light,and the best luminescence intensity sample 0.5Er³⁺doped Ca_1.5Y_1.5Al_3.5Si_1.5O₁₂was obtained.The near-infrared light intensity of Er³⁺increases by 4.2 times due to the introduction of the sensitized ion Ce³⁺in the sample Ca_1.5Y_1.5Al_3.5Si_1.5O₁₂:0.5Er³⁺.To estimate the energy transfer efficiency of Ce³⁺→Er³⁺,the fluorescence lifetimes of Ce³⁺in samples with different Er³⁺doping concentrations were tested.By testing the emission and excitation spectra as well as the lifetime curves of the samples,it could know that the energy transfer manners of Ce³⁺→Er³⁺has radiative reabsorption and nonradiative energy transfer two mechanisms.The total energy transfer efficiency of Ce³⁺→Er³⁺reaches 95.5%,and the cross-relaxation of Ce³⁺and Er³⁺further enhances the near-infrared luminescence of Er³⁺.