Cr,In共掺杂MgGa2O4小尺寸近红外长余辉纳米颗粒的制备及发光性能

采用乙二醇辅助共沉淀法制备了小尺寸Cr,In共掺杂MgGa₂O₄(MGO∶Cr, In)近红外长余辉发光纳米粒子(Persistent luminescence nanoparticles, PLNPs), 并考察了Cr, In共掺杂及煅烧温度对MGO晶体结构、 余辉发光性质和尺寸的影响. 结果表明, 最优Cr, In共掺杂浓度分别为0.3%和0.02%, MGO∶Cr, In晶体属于Fd3m空间群, Cr, In共掺杂对纳米颗粒的结构无影响, 平均粒径为(8.61±2.23) nm, 分散性良好, 最佳煅烧温度为700 ℃. 并且, In掺杂可有效延长其余辉发光寿命, 平均发光寿命(τ_av)从49.33 s增大至52.89 s; 荧光量子产率增高至44.9%; 活化能E_a为(0.36±0.04) eV, 具有良好的热稳定性; 陷阱深度为0.696 eV. 此外, 该PLNPs分别在260 nm、410 nm和600 nm处有激发峰， 表明UV光、 蓝绿光以及红光皆可实现对其的激发， 发射波长皆位于705 nm处， 属于Cr³⁺的²E(²G)→⁴A₂(⁴F)跃迁. 该PLNPs在红色LED灯、 光学储器件以及生物医学等领域具有巨大潜在应用价值.

Synthesis and Luminescence Properties of Cr,In Co-doped Small Size MgGa2O4 Near-infrared Persistent Luminescence Nanoparticles

Cr， In co-doped MgGa₂O₄ persistent luminescence nanoparticles（PLNPs） with small-size were prepared by ethylene glycol assisted co-precipitation. The influence of Cr，In co-doping and calcination temperature on the MGO crystal structure， afterglow luminescence properties and size were further investigated. The results showed that the optimal Cr，In co-doped concentrations were 0.3% and 0.02%， respectively， and the samples belonged to Fd3m space group， Cr，In co-doping had no effect on the structure of the samples. The PLNPs had a good water dispersibility with an average particle size of （8.61±2.23） nm and the optimum calcination temperature of 700 ℃. Moreover， the afterglow decay life was prolonged by In doping， and the average luminescence life（τ_av） of the afterglow decay fitting curves increased from 49.33 s to 52.89 s with the QY increased to 44.9%. The activation energy（E_a） was （0.36±0.04） eV. The PLNPs had a good thermal stability， and the trap depth was 0.696 eV. Moreover， the PLNPs had three excitation bands at 260， 410 and 600 nm， respectively， which indicated that UV light， blue-green light and red light could be excited， and the emission wavelength was all at 705 nm， belonged to the ²E（²G）→⁴A₂（⁴F） transition of Cr³⁺. Therefore， the PLNPs had a great potential application value in red LED lamps， optical storage devices and biomedical fields.