Wydział Chemii

Paulina Bolek

Yiquan Wu

Yan Yang

Eugeniusz Zych

2020

Optical Materials

105

109877/1-109877/8

10.1016/j.optmat.2020.109877

Naukowa

Angielski

Artykuł

Photoluminescence, radioluminescence, and thermoluminescence of transparent alumina in the range 15–800 K is presented. Blue 4f⁶5d¹→4f⁷(⁸S_7/2) 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 ²E_g→⁴A_2g 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.

Alumina, Transparent ceramics, Eu2+ luminescence, Cr3+, F-center

http://dx.doi.org/10.1016/j.optmat.2020.109877

http://www.elsevier.com