Sn2+/Pb2+ Doping-Induced Highly Transparent Boroaluminate Microcrystalline Glass With Deep Traps for Long-Term Optical Storage and Time-Lapse X-ray Imaging

Abstract

The development of microcrystalline glass-ceramics with high transparency and deep trap energy levels is crucial for the cost-effective and large-scale production of scintillators and optical data storage applications. In this study, the incorporation of highly electronegative divalent tin (Sn²⁺) plays a key role in modulating the network structure of borate glass. This leads to the successful synthesis of SrAl₂O₄:Eu²⁺ microcrystalline glass with high transparency, reaching up to 80%, and excellent crystallinity. Additionally, a series of non-optically active ions with different valence states is co-doped with Eu²⁺ to fine-tune the trap levels of the SrAl₂O₄ microcrystals. All samples maintain high crystallinity and exhibit good transparency. In particular, the Pb²⁺ ion co-doped samples achieve an increased trap energy level of 1.28 eV, significantly enhancing their capacity to capture X-rays and ultraviolet light. Density functional theory calculations reveal that this enhancement is due to severe lattice distortion caused by Pb²⁺ ions occupying interstitial sites in SrAl₂O₄. Utilizing the SrAl₂O₄:Eu²⁺, Pb²⁺ glass-ceramics materials, X-ray imaging with a delay of up to 210 s and optical information storage for >60 d is achieved. This study provides valuable insights into the crystal growth and trap modulation of persistent luminescent materials within a three-dimensional glass network structure.