A Study Of Gadolinium Aluminate Luminescence Material By Combinatorial Materials Chip Method

The combinatorial materials chip method is an excellent innovation for inorganic function material research.The technique is capable of efficiently discovering and screening new materials.In present work,a new luminescence material system, Gadolinium aluminate doped with rare earth ions,was investigated,and a database of this material system was set up.Some major issues associated with luminescence materials,such as host materials,activator and activator/sensitizer concentrations,were well taken into consideration in the process of materials chip design.With the utilization of IM100 ion beam deposition system,which is the first platform for combinatorial materials chip synthesis in China,a series of gadolinium aluminate luminescence materials chips were fabricated.Powder synthesis methods were also studied as the experimental basis.The main content and results of this research work are listed as follows:1) Gadolinium aluminate luminescence material doped with rare earth ions was studied by combinatorial method,including data collection of the luminescent properties and rule derivation with the first principle calculation.Scanning electron microscopy (SEM),X-ray diffraction phase analysis(XRD),Auger electron spectroscopy(AES) emission and excitation photoluminescence spectra(PL),photoluminescence photos techniques were used as analysis methods.Based on experiments,GdAlO₃(GAP) was selected as the optimal host material in the gadolinium aluminate;luminescence spectra data of rare earth ions(RE=Ce,Pr,Sm,Eu,Tb,Dy) doped gadolinium aluminate were gathered;It was found that the Eu or Tb ion doped gadolinium aluminate can emit strong visible photoluminescence under UV excitation.2) The most suitable annealing condition for gadolinium aluminate single phase film synthesis was investigated.The stoichiometric gadolinium aluminate multiplayer thinfilm precursors(single layer thickness was less than 500A) were treated at 400℃/120 h+1300℃/4 h,and final products of GdAlO₃(GAP) and Gd₄Al₂O₉(GAM) single phase films were formed.For Gd₃Al₅O₁₂(GAG) phase stoichiometric precursor,the high temperature crystallization should be 1200℃/4h while the low temperature diffusion was the same.The XRD,AES analysis indicated that such two-step annealing processes would form pure single phase films,and the SEM analysis further proved that uniform and dense films were obtained.3) Powder synthesis for gadolinium aluminate luminescence materials.XRD,TGDSC and thermodynamics calculation were used as analysis methods.After obtaining the precursor powder from citrate-nitrate combustion process,≥900℃/2h annealing could form GAP,GAM single phase powder,the annealing condition should be changed to 900℃/1h(the temperature should be kept precisely at 900℃) when fabricating GAG. Acetate-nitrate combustion was also used to synthesis the gadolinium aluminate luminescence powder.It was found that 1100℃/2h for GAP,and 850℃/2h+900°/1h for GAG were the suitable heat treatment conditions.However,GAM single powder could not be obtained by this method.