Energy transfer and annealing behavior of luminescence in Dy-doped PbWO4 single crystal

The Dy³⁺: PWO single crystal was subsequently annealed in air atmosphere at a temperature of 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, and 1000°C, respectively. X-ray excited luminescence spectra were measured before and after each step of annealing. Annealing experiments confirmed the energy transfer-taking place from PbWO₄ (PWO) host to Dy³⁺ ions, followed by the enhancing characteristic emission of Dy³⁺ ions. In the process of annealing, the luminescence of PWO host was significantly reduced while that of Dy³⁺ was increased simultaneously. Annealing at a temperature below 700°C suppressed the blue luminescence of the PWO host and enhanced its green components, while the emission of Dy³⁺ is increased to some extent. Further annealing at higher temperature strongly reduced the luminescence of the PWO host, while the emission of Dy³⁺ was greatly increased. Interstitial oxygen O_i could play an important role in the luminescence. Annealing could modify the luminescence of Dy³⁺ ions in PWO, which may be useful in terms of some application purposes.