Ce3+:Lu3Al5O12–Al2O3 optical nanoceramic scintillators elaborated via a low-temperature glass crystallization route

Abstract

Transparent Ce:lutetium aluminum garnet (Ce:Lu3Al5O12, Ce:LuAG) ceramics have been regarded as potential scintillator materials due to their relatively high density and atomic number (Zeff). However, the current Ce:LuAG ceramics exhibit a light yield much lower than the expected theoretical value due to the inevitable presence of LuAl antisite defects at high sintering temperatures. This work demonstrates a low-temperature (1100 ℃) synthetic strategy for elaborating transparent LuAG–Al2O3 nanoceramics through the crystallization of 72 mol% Al2O3–28 mol% Lu2O3 (ALu28) bulk glass. The biphasic nanostructure composed of LuAG and Al2O3 nanocrystals makes up the whole ceramic materials. Most of Al2O3 is distributed among LuAG grains, and the rest is present inside the LuAG grains. Fully dense biphasic LuAG–Al2O3 nanoceramics are highly transparent from the visible region to mid-infrared (MIR) region, and particularly the transmittance reaches 82% at 780 nm. Moreover, LuAl antisite defect-related centers are completely undetectable in X-ray excited luminescence (XEL) spectra of Ce:LuAG–Al2O3 nanoceramics with 0.3–1.0 at% Ce. The light yield of 0.3 at% Ce:LuAG–Al2O3 nanoceramics is estimated to be 20,000 ph/MeV with short 1 μs shaping time, which is far superior to that of commercial Bi4Ge3O12 (BGO) single crystals. These results show that a low-temperature glass crystallization route provides an alternative approach for eliminating the antisite defects in LuAG-based ceramics, and is promising to produce garnet-based ceramic materials with excellent properties, thereby meeting the demands of advanced scintillation applications.

Keywords

• glass crystallization
• garnet antisite defects
• lu3al5o12–al2o3 (luag–al2o3) transparent ceramics
• nanoceramics
• scintillation