LiTaO3:Bi3+,Tb3+,Ga3+,Ge4+: A Smart Perovskite with High Charge Carrier Storage Capacity for X-Ray Imaging, Stress Sensing, and Non-Real-Time Recording

Developing X-ray or UV-light charged storage and mechanoluminescence (ML) materials with high charge carrier storage capacity is challenging. Such materials have promising utilization in developing new applications, for example, in flexible X-ray imaging, stress sensing, or non-real-time recording. Herein, the study reports on such materials; Bi3+, Tb3+, Ga3+, or Ge4+ doped LiTaO3 perovskite storage and ML phosphors. Their photoluminescence, thermoluminescence (TL), and ML properties are studied. The charge carrier trapping and release processes in the Bi3+, Tb3+, Ga3+, or Ge4+ doped LiTaO3 are explained by using the constructed vacuum referred binding energy diagram of LiTaO3 including the energy level locations of unintended defects, Tb3+, Bi3+, and Bi2+. The ratio of the TL intensity after X-ray charging of the optimized LiTaO3:0.005Bi(3+),0.006Tb(3+),0.05Ga(3+), or LiTaO3:0.005Bi(3+),0.006Tb(3+),0.05Ge(4+) to that of the state-of-the-art BaFBr(I):Eu2+ is approximate to 1.2 and 2.7, respectively. Force induced charge carrier storage phenomena is studied in the Tb3+, Bi3+, Ga3+, or Ge4+ doped LiTaO3. Proof-of-concept compression force distribution sensing and X-ray imaging is demonstrated by using optimized LiTaO3:0.005Bi(3+),0.006Tb(3+),0.05Ga(3+) dispersed in a hard epoxy resin disc and in a silicone gel film. Proof-of-concept color-tailorable ML for anti-counterfeiting is demonstrated by admixing commercial ZnS:Cu+,Mn2+ with optimized LiTaO3:0.005Bi(3+),0.006Tb(3+),0.05Ge(4+) in an epoxy resin disc.

Automated summary

This study focuses on developing X-ray or UV-light charged storage and mechanoluminescence materials with high charge carrier storage capacity, using Bi3+, Tb3+, Ga3+, or Ge4+ doped LiTaO3 perovskite phosphors. The properties of these materials, including photoluminescence, thermoluminescence, and ML, are studied, and the charge trapping and releasing processes are explained using energy level diagrams. The optimized materials show promising results for applications such as X-ray imaging and stress sensing, with a ratio of TL intensity comparable to state-of-the-art materials. Additionally, force-induced charge carrier storage and color-tailorable ML for anti-counterfeiting purposes are also demonstrated.