Preparation And Properties Of Co-doped MgGa₂O₄ And Triple-doped β-Ga₂O₃ Persistent Luminescence Nanomaterials

Persistent luminescence nanomaterials are nanomaterials that can absorb and store external excitation energy such as ultraviolet light and X-ray,and still emit light after stopping excitation.Recently,due to its unique advantages of no background interference,deep tissue penetration and no excitation,it has important application prospects in biomedical field,especially near-infrared persistent luminescence nanomaterials.However,the research on near-infrared persistent luminescence nanomaterials is still in the initial stage,and its afterglow properties need to be further improved.Doping various rare earth ions can improve the afterglow properties of near-infrared persistent luminescence nanomaterials and make them have better biological tissue penetration ability.At present,a variety of persistent luminescence matrix materials have been developed,such as aluminate,silicate,gallium oxide and gallate.Among them,gallium oxide（Ga₂O₃）and magnesium gallate（MgGa₂O₄）matrix have good wide band gap,natural defects and high proportion of reverse defects respectively,which makes them have good research value.The main research of this paper are as follows:（1）Cr³⁺,Ca²⁺co-doped and Cr³⁺,Ca²⁺,Pr³⁺triple-dopedβ-Ga₂O₃near-infrared persistent luminescence nanomaterials were developed by hydrothermal method and subsequent calcination.The results show that Ca,Pr doping can effectively enhance the persistent luminescence properties of theβ-Ga₂O₃:Cr near-infrared persistent luminescence nanomaterials;the afterglow time exceeds 8 days;the signal-to-noise ratio（SNR）is 272;the fluorescence quantum yield（QY）is as high as 74.8%;it can be re-excited by LED lamp and store information at high temperature.Syntheticβ-Ga₂O₃:Cr³⁺,Cr³⁺,Pr³⁺near-infrared persistent luminescence nanomaterials have great potential in optical storage.（2）Small size near-infrared luminescent Cr,Al co-doped MgGa₂O₄（Mg O:Cr,Al）persistent luminescence nanomaterials were prepared by ethylene glycol assisted co-precipitation method.The effect of Al doping on the optical properties of MGO:Cr was investigated.The results show that Al doping has no effect on the crystal structure of MGO:Cr;the average particle size is～6.53±1.79 nm;the optimal Al doping concentration is 0.4%;the average trap energy levels（E）are 0.698 ev and 1.064 ev,respectively;the afterglow fitting average luminous life(τ_av)increased from 46.98 s to 78.75 s,which provides basic material support for the application of MGO near-infrared persistent luminescence nanomaterials.（3）Small size Cr,In co-doped MgGa₂O₄（Mg O:Cr,In）near-infrared persistent luminescence nanomaterials were successfully prepared by ethylene glycol assisted co-precipitation method.The effects of Cr,In co-doping and calcination temperature on the crystal structure,afterglow luminescent properties and size of MGO were investigated.The results show that the optimum co-doping concentrations of Cr and In are 0.3%and 0.02%respectively,belonging to the Fd3m space group;the In,Cr co-doping has no effect on the crystal structure;the average particle size is～8.61±2.23 nm;good dispersibility;the optimum calcination temperature is 700℃.Moreover,the In doping can effectively prolong its afterglow luminescence life and its average luminescence life(τ_av)increased from 49.33 s to 52.89 s;the fluorescence quantum yield increased to 44.9%;the activation energy（Ea）is 0.36±0.04 e V,which has good thermal stability;the trap depth was 0.696 e V,and the drug loading and release of doxorubicin（DOX）were studied in vitro.The results show that it has good p H effects and can achieve the high release rate of doxorubicin hydrochloride（DOX）in the tumor weak acid environment.In conclusion,the near-infrared persistent luminescence nanomaterials have great potential application value in red LED lamps,optical storage devices,biomedicine and other fields.