Violet-blue up conversion photostimulated luminescence properties and first principles calculations of a novel un-doped CaZrO3 phosphor for application in optical storage

Un-doped CaZrO3 has been synthesized using a solid state reaction at 1400 degrees C and shown to have the perovskite structure. The CaZrO3 showed a broad violet-blue photostimulated emission band in the range 320-550 nm when stimulated by a 980 nm infrared laser. The long lasting phosphorescence of CaZrO3 was very weak and lasted for only 94 s, indicating that there are few shallow traps in the CaZrO3. The investigations of the thermoluminescence revealed that at least two types of deep traps (445 and 494 K) existed in CaZrO3 and their depths were calculated to be 1.13, 1.55 eV, respectively. These traps in CaZrO3 were proved to be linked; the stability of the deep traps could be slightly influenced by shallow traps. The thermoluminescence signals of the deep traps retained about 84% of the original intensity even after 72 h. This indicated that the CaZrO3 with stable deep traps was worthy of application in the optical storage field. It revealed that the shallow traps (315 K) and some of the deep traps (445 and 494 K) were involved in the weak, long lasting phosphorescence. The deep traps mainly contributed to the photostimulated luminescence. A first principles calculation within the local density approximation of density functional theory was applied to calculate the electronic structure and linear optical properties of CaZrO3. Finally, mechanisms for the photoluminescence, long lasting phosphorescence, and photostimulated luminescence of CaZrO3 material are proposed. (C) 2012 Elsevier B.V. All rights reserved.