Multifunctional materials with optical temperature sensing and anti-counterfeiting properties have vast application prospects in our daily life, but the development of them still faces huge challenges. Herein, a novel SrY 2 O 4 :Bi 3+ ,Er 3+ phosphor with multicolor luminescence was synthesized triumphantly. Stimulated by different ultraviolet (UV) lights, the sample exhibits blue or green emissions, while emits yellow up-conversion luminescence under 980 nm laser irradiation. Interestingly, abnormal thermal quenching and thermal stimulation enhanced persistent luminescence are realized in SrY 2 O 4 :Bi 3+ ,Er 3+ . Benefiting from the distinct responses of Bi 3+ and Er 3+ luminescence to temperature, thermochromism is verified when excited by UV or 980 nm light. Furthermore, the color shift from yellow-green to dark yellow is seen as the 980 nm laser power density reduces or the distance between laser source and the sample increases. Based on the luxuriant luminescence properties, multimode optical temperature sensing and dynamic anti-counterfeiting are constructed. All findings indicate that the multicolor emissive SrY 2 O 4 :Bi 3+ ,Er 3+ material offers a fresh outline for the exploitation of multiple optical thermometry and anti-counterfeiting.
Hanyu Hu,Zeyu Lyu,Dashuai Sun,Shuai Wei,Jia Liu,Xin Wang,Luhui Zhou,Hongpeng You
Although there have been numerous reports on broadband near-infrared (NIR) emitting phosphors, their emissions are mainly concentrated in the range of 700–1000 nm (NIR-I). Herein, we successfully synthesized a broadband near-infrared phosphor CaMgGeO4:Cr4+(CMG:Cr4+) with an emission in the range of 1000–1600 nm (NIR-II). The introduction of Er3+ ions into CMG:Cr4+ resulted in a wider near-infrared emission phosphor CaMgGeO4:Cr4+,Er3+ (fwhm = 361 nm), compensating for the luminescence of 1500–1600 nm. More importantly, an energy transfer from Cr4+ to Er3+ ions has been discovered. Furthermore, a NIR pc-LED was fabricated by combining the CMG:Cr4+,Er3+ phosphor with a 590 nm chip. The changes in intensity and profile of the transmission spectra of light passing through different liquids reveal its potential application in organic compound recognition. This work opens a direction for the development of NIR-II phosphors.