Designing Color-tunable luminescent thermometers and information encryption based on Pr3+ or Sm3+ doped SrNb2O6: Tb3+ phosphors via energy transfer

Color-tunable luminescence intensity ratio thermometers and information encryption are firstly designed through different energy transfer mechanism. Herein, two types thermometric materials, SrNb2O6: Tb3+, Pr3+ and SrNb2O6: Tb3+, Sm3+ are prepared. The Tb3+ and Pr3+ typical emissions show luminescence mechanism between two intervalence charge transfer states. Whereas, Tb3+ and Sm3+ emissions are related to energy migration from intervalence charge transfer state to 4f level. Interestingly, (5D4 & RARR;7F5)Tb3+/(1D2 & RARR;3H4)Pr3+ or (5D4 & RARR;7F5)Tb3+/(4G5/2 & RARR;6H7/2)Sm3+ have different temperature sensing properties due to distinct energy transfer processes and provide visualization of temperature measurement. The former gains high sensitivity (Sa = 0.012 K-1) at high temperature region, and the latter reach as high as Sa = 0.028 K-1 at low temperature. Besides, using multi-mode color emission of Tb3+ or Pr3+ doped SrNb2O6 achieves information hiding. This work not only shows new strategy to develop high-efficiency luminescent thermometers but also develop flexible optical encryption technology.

Automated summary

Color-tunable luminescence intensity ratio thermometers and information encryption are designed using different energy transfer mechanisms. Two types of thermometric materials, SrNb2O6: Tb3+, Pr3+ and SrNb2O6: Tb3+, Sm3+, are prepared. The temperature sensing properties of (5D4→7F5)Tb3+/(1D2→3H4)Pr3+ and (5D4→7F5)Tb3+/(4G5/2→6H7/2)Sm3+ are different due to distinct energy transfer processes, providing visualization of temperature measurement. Additionally, multi-mode color emission of Tb3+ or Pr3+ doped SrNb2O6 enables information hiding.