Radiation-induced changes in the photoluminescence properties of NaMgF3:Yb nanoparticles: Yb3+ → Yb2+ valence conversion and oxygen-impurity charge transfer

Abstract Strained cuboid Yb-doped NaMgF3 nanoparticles were synthesised via a hydrothermal synthesis technique. The morphologies and crystal phases of the nanoparticles were the same for two different Yb concentrations (0.1% and 1%). Prior to X-ray exposure, photoluminescence was observed from O2− impurities, Yb3+, and Yb2+. The infrared Yb3+ luminescence could be excited using ultraviolet stimulation via an O2− → Yb3+ charge transfer process that also sensitised the emission. After X-ray exposure the intensity of the Yb2+ luminescence increased due to the radiation-induced conversion Yb3+ → Yb2+, indicating that Yb3+ acted as an electron trap. This radiophotoluminescence effect could find applications in radiation dose detection and monitoring, where the intensity of the Yb2+ emissions are proportional to the absorbed dose.