We examined the photoluminescent behaviors of MgSiN2:Mn2+ and MgSiN2:Ce3+,Mn2+ phosphors for use in white-light-emitting diodes. The red emission from MgSiN2:Mn2+ phosphors consisted of two Gaussian components, P1 from a single Mn2+ ion and P2 from either Mn2+ pairs or clusters. Decay analysis based on the Yokota and Tanimoto equation identified long decay for P1 and fast decay for P2. Most importantly, Ce3+ codoping enhanced Mn2+ emission intensity; in particular, emission at 460 nm excitations was promoted by the Ce3+ codoping.

No abstract

No abstract

In this study, we report highly transparent yttria ceramics fabricated by a facile hot‐pressing method with tantalum foil shielding which effectively prevents the ceramic samples from carbon contamination caused by the graphite mold used during the process. The hot‐pressed sample was already highly transparent without a post‐annealing step or hot isostatic pressing. For a 2‐mm‐thick specimen doped with 1 at.% ZrO2, the in‐line transmittance reaches 74.4% at 400 nm and 81.1% at 1100 nm. The sample shows a very fine microstructure with an average grain size of about 1 μm owing to the low sintering temperature of only 1600°C. The study results indicate that it is possible to produce transparent yttria ceramics with excellent optical transparency using the economical and convenient hot‐pressing method.

No abstract

No abstract

No abstract

No abstract