Tailoring traps in Eu2+ activated persistent phosphors for multilevel information storage and encryption

Abstract

Persistent luminescence (PersL) phosphors, identified as ideal candidates, hold immense promise for information storage and encryption. However, practical storage and encryption technology using these phosphors remains uncommon due to their weak luminescence intensity and the inconvenience of light sources used in encryption and decryption processes. Here, we have developed Sr2MgSiGeO7:Eu2+,Mn2+,Dy3+ phosphor with a super-long PersL beyond 100 h, the higher charge storage capacity and PersL efficiency (17 %) than commercial SrAl2O4:Eu,Dy phosphors by introduction of co-dopant Mn2+. This phosphor exhibits rapid and efficient charging capability when exposed to various light sources such as sunlight, light-emitting diode, mobile phone and computer screen. To explain the high charge storage capacity and super-long PersL, we propose a novel trap mechanism based on hole-electron defect pair trap structures. Notably, this phosphor as an anti-counterfeiting material demonstrates high-order encryption by the adding specific information writing process via temperature management. This study provides a new paradigm for future design of PersL phosphors and luminescent anti-counterfeiting.