Sunlight-excited infrared long persistence of SrAl2O4: Eu2+, Dy3+, Er3+/ Nd3+ nanophosphors

Abstract

Strontium aluminate co-doped with divalent europium, trivalent dysprosium ions 2+3+(SrAl2O4: Eu, Dy) shows a green demonstrated long persistence lasting for up to 15 hours 3+3+under sunlight excitation. The research presented in this thesis focus on the Er/ Nd activated 2+infrared (IR) long persistence due to the persistent energy transfer process in SrAl2O4: Eu, 3+3+3+Dy, Er/ Nd nanophosphor system. The XRD, SEM, EDX and optical spectra analysis method are employed to characterize the phosphors synthesized by combustion route. The 2+3+3+efficient energy transfer process from sensitizer Eu to the activator Er/ Nd in SrAl2O4 host system is investigated. Meanwhile, the long persistence luminescence in IR region is obtained. To our knowledge, there is no related material system regarding sunlight-excited infrared long persistence nanophosphor reported. 2+3+3+3+