Cerium-doped lutetium aluminum garnet phosphors and optically transparent ceramics prepared from powder precursors by a urea homogeneous precipitation method

Nanosized, purified crystalline-phase cerium-doped lutetium aluminum garnet (LuAG:Ce) phosphors were prepared by the urea homogeneous precipitation method. The obtained phosphors showed much higher dispersivity, a fairly uniform size of about 30 nm, and higher luminescence intensity than those synthesized by a sol-gel combustion process. The radioluminescence spectrum of the phosphors consisted of two emission bands owing to the transitions from the lowest 5d excited state to the 4f ground state of Ce(3+). The transmittance in the visible light region of the transparent ceramics fabricated at 1800 degrees C for 10 h under a higher vacuum of 1.5 x 10(-3) Pa using the prepared powders reached 70% and the attenuation coefficient decreased to 0.116 mm(-1), which caused much higher luminescence intensity. Compared with those reported previously, the optical properties of the LuAG:Ce transparent ceramics fabricated in the present work improved markedly.