Photo- radio- and thermoluminescence of sintered transparent Al2O3:Eu2+ in the range 15–800 K

Abstract Photoluminescence, radioluminescence, and thermoluminescence of transparent alumina in the range 15–800 K is presented. Blue 4f65d1→4f7(8S7/2) luminescence of Eu2+ exclusively under ultraviolet excitation at ~280 nm was observed and its thermal stability was evaluated. Excitation with X-rays produced violet broad band peaking around 380 nm as well as infrared luminescence of Cr3+ impurity around 694 nm due to the 2Eg→4A2g transition. The temperature dependence of both these emissions was tested. The infrared luminescence could be effectively excited through broad bands peaking at ~400 and 550 nm. A Well-resolved vibronic structure of the 550 nm excitation band of Cr3+ is discussed. Significant red-shift of the Cr3+ luminescence was observed with increasing temperature. Both Cr3+ ion, as well as intrinsic defect(s) of F-type center, are active in thermoluminescence of that transparent ceramic material. Detailed analysis of thermoluminescence generated by the F-center showed a set of traps in a broad range of temperatures (40–570 °C). Their thermoluminescence is government by first-order kinetics. Continuous distribution of trap energies was proved. A vacuum referred binding energy scheme including centers involved in the luminescence of the system is presented.