|About this Abstract
||MS&T23: Materials Science & Technology
||Solid-state Optical Materials and Luminescence Properties
||Ultraviolet Excitation of Trivalent Europium in Alumina
||John Kenneth Krebs, Alex Sobey-Strick
|On-Site Speaker (Planned)
||John Kenneth Krebs
The luminescent properties of lanthanide impurity ions in metal oxide hosts make good candidates for device phosphors. The optical transitions between 4f electronic levels in the lanthanides enable color selection but suffer from low quantum transition probabilities, which limit their efficiency. However, other physical mechanisms for exciting the lanthanides can enhance their excitation efficiency. In this work, we study the UV excitation of europium impurities in the aluminum oxide host. Combustion synthesis reactions result in doped alumina samples of definite crystal structure with particle sizes around 30 nm. Optical spectroscopic techniques verify the f-f energy level transitions identified as impurities occupying the aluminum cation sites. Ultraviolet excitation (266 nm) leads to broader emission peaks than resonant (visible) excitation. Ultraviolet excitation measurements allow the distinction between charge transfer excitation of the main site and that of a poorly ordered phase, likely associated with impurities at grain boundaries.