Y3Al5O12Ce

Y3Al5O12Ce, commonly abbreviated YAG:Ce, is a cerium-doped yttrium aluminum garnet. The host lattice, Y3Al5O12 (YAG), has a cubic garnet structure, and Ce3+ ions substitute for Y3+ sites in the crystal. The activator centers enable luminescence through allowed 5d-4f electronic transitions, producing broad yellowish emission.

Emission and properties: YAG:Ce emits a broad yellow to green-yellow band with a peak around 530–550 nm when excited by blue or near-UV light. The emission is relatively broad due to the nature of the 5d-4f transitions, and the material offers a fast decay suitable for pulsed applications. It is chemically and thermally stable, and can be processed as powders, ceramic bodies, or single crystals. Typical cerium dopant concentrations range from a fraction of a percent to a few percent, chosen to optimize brightness while minimizing concentration quenching.

Synthesis and forms: YAG:Ce can be produced by traditional solid-state synthesis and then formed into powders or ceramics, or grown as single crystals by methods such as the Czochralski process or other crystal-growth techniques. The material is commonly used in optoelectronic and scintillation contexts, and can be incorporated into composites or deposited as phosphor layers in devices.

Applications: The most widespread use of YAG:Ce is as a phosphor in white light-emitting diodes, where blue or near-UV LEDs excite the material to produce white light through color mixing. It is also employed as a scintillator in gamma- and X-ray detectors due to its bright emission and fast response, as well as in certain radiation-sensing and imaging applications.