Highly transparent cerium-doped yttria ceramics for full-band UV-shielding window applications

Highly transparent cerium-doped yttria ceramics were fabricated via a pressureless sintering method with an addition of 10 at.% La 2 O 3 and 1 at.% ZrO 2 as a binary sintering additive. With an increase in the Ce doping concentration from 0 to 3 at.%, the optical absorption edge of yttria ceramics exhibited a significant red shift from 290 to 380 nm as a result of the 4f–5d transition of Ce 3+ and the charge transfer of Ce 4+ (i.e., Ce 4+ +e – →Ce 3+ ). For a 2-mm thick sample doped with 3 at.% Ce, the total ultraviolet radiation (UV) transmittance (220–400 nm) is only 1.7%, indicating a nearly complete UV absorption. Meanwhile, the specimens possess high in-line transmittance levels in both the visible and the infrared regions (i.e., >70% at 450 nm and ∼80% at 1100 nm). Additionally, the present specimens were confirmed to have good enough mechanical strength levels (∼165 MPa) and thermal conductivity (∼5 W/m·K), which are comparable or even better compared to those of previously reported transparent yttria ceramics. The results of this work indicate that cerium-doped transparent yttria ceramics are promising candidate materials for full-band UV-shielding window applications.