Wide-responsive-range multicolor temperature-dependent photoluminescence of LiYW2O8/LiYW2O8:Eu3+ phosphors for anti-counterfeiting

Temperature-dependent photoluminescence (PL) strongly depends on temperature and can be applied for non-contact PL anti-counterfeiting. However, it still needs a temperature-dependent PL phosphor with significant PL color changes over a wide range around room temperature. In this work, the LiYW2O8/LiYW2O8:Eu3+ phosphors are presented. The PL of the phosphors consists of a broadband host emission and narrow Eu3+ emissions, which show significantly different temperature dependences over a large range (room temperature +/- 160 degrees C). It indicates that as the temperature increases from -140 degrees C to 180 degrees C, the PL color of the LiYW2O8 changes from green to blue and that of the LiYW2O8:Eu3+ changes from green-blue to red. Based on the unique multicolor temperature-dependent PL, a PL anti-counterfeiting logo is designed based on the LiYW2O8/LiYW2O8:Eu3+ phosphors and polydimethylsiloxane (PDMS) polymer. The results show that the PL color of the logo significantly changes with temperature, and therefore the LiYW2O8/LiYW2O8:Eu3+ phosphors are promising for designing PL anti-counterfeiting.