Experimental Optimization Design Dominant Luminescence Properties Of Rare Earth BaGd₂ZnO₅ Phosphor

Rare earth doped luminescent upconversion?UC?materials,which presents practical and potential applications in lots of many fields such as infrared detection,biological fluorescence label,three-dimensional display and laser anti-counterfeit,have attracted much attention and have been widely investigated.The investigation is focused on improving synthesis method,exploring luminous mechanism and enhancing luminescence efficiency.With the development of modern technology,the experimental optimization design method successfully solved the object optimization of research project,engineering design etc.In this work,the luminescence of Er³⁺/Yb³⁺ codoped BaGd₂ZnO₅ phosphors was investigated by experimental optimization design and obtained the optimized doping concetration corresponding to the best UC luminescent intensity of the phosphors.The research also discussed the luminance property and energy transfer mechanism of doped BaGd₂ZnO₅ phosphors.The main content and results are included as follows:1.A whole optimized design method was adopted in the experiment.The regression equation was effectively built to display the relationship between green?red?luminescent intensity and Er³⁺/Yb³⁺ dopant concentration.The optimal Er³⁺/Yb³⁺ doping concentration corresponding to the two luminescent intensities were calculated by genetic algorithm.The optimal samples were synthesized by conventional high temperature solid state method and X-ray diffraction?XRD?examination analysis showed the samples were pure phase.The UC emission spectra for the products were measured under a 980 nm fiber laser excitation.The constraint relationship between green?red?UC emission intensities and working currents shows the two emissions both are ascribed to 2-photon process.The energy level gap difference between 2H_11/2 level and 4S_3/2 level was calculated by analyzing temperature-dependent green emission.2.A series of various Er³⁺ concentrations single doped and various concentrations of Er³⁺ or Yb³⁺ codoped BaGd₂ZnO₅ phosphors were prepared through high temperature solid state method.It was confirmed that all samples exhibited pure phase as BaGd₂ZnO₅ by XRD analysis.The UC emission spectra for all samples were collected upon 980 nm excitation under with the same experimental conditions,meanwhile the dependence of UC emission intensity on the laser working current was analyzed,and the two-photon process was confirmed to generate the green and red emissions.3.Various cosolvents and Ho³⁺ concentration doped BaGd₂ZnO₅ phosphors with fixed Er³⁺/Yb³⁺ concentration were synthesized via traditional high temperature solid reaction.The XRD patterns indicated the present products are pure phase,Ho³⁺ ion doping concentration and different cosolvents did not cause obvious difference of the crystal structure.For studying the dependence of emission intensity on the laser working current,the UC emission spectra of all the samples were measured at the same experimental conditions by 980 nm excitation.The red and green emission in Ho³⁺ doped sample belong to 2-phonon process based on the variation of emission intensity with increasing working current,and the mechanism of energy transfer was discussed.In addition,the temperature-dependent UC luminescence in Er³⁺/Yb³⁺/Ho³⁺ tri-doped samples was studied,it is seen that the thermal quenching is caused and the luminescence intensity decreases with increasing temperature.Finally,the activation energy of the samples was calculated.4.The various Ce³⁺ concentration doped BaGd₂ZnO₅:Er³⁺/Yb³⁺/H₃BO₃ phosphors were prepared by means of temperature solid state method.The red emission and green emission centered at 662,551 and 527 nm were observed in UC emission which was monitored at 980 nm laser.2-phonon process contributed to UC emission and the energy transfer was discussed according to emission intensity varying with working currents.