The left-hand Figure shows multicolor emitting (Gd,Ln)3(Al,M1/M2)5O12:RE3+ phosphors, where Ln is a lanthanide element, M1 and M2 are 2+ and 4+ charged dopant ions, respectively, and RE3+ is an activator ion. The compounds were derived by modifying the Gd and Al sites of Gd3Al5O12 garnet (GAG), and such a strategy not only stabilized the metastable lattice of GAG but also produced multicolor luminescence by doping different types of activators.

The right-hand Figure shows the (Y,Gd)2O3:Eu3+ transparent ceramics, which were fabricated via vacuum sintering at only 1700 °C for 4 h but are as transparent as the corresponding single crystals. The oxide powders used for sintering were obtained by engineering of layered hydroxide nanosheets, including composition design and thickness control, followed by proper calcination. The derived oxide particles showed high dispersion, high specific surface area and unimodal size distribution, revealing the significant advantages of the synthesis technology.

The right-hand figure shows an SEM image and the powder X-ray diffraction (XRD) pattern of high-entropy ceramic powder synthesized via a liquid-phase method. By synthesizing powders of candidate compositions, that was previously selected through screening process in advance, we successfully produced raw powders of a single garnet phase having fine particle sizes in the 70–80 nm using this liquid-phase approach. Furthermore, by consolidating these powders into bulk form using a current-assisted sintering technique, we achieved to fabricate polycrystalline transparent ceramics with complex compositions. We are currently working to further enhance transparency and evaluate optical properties, aiming to achieve higher functionality.