Transparent Ce:GdYAG ceramic color converters for high-brightness white LEDs and LDs

Transparent Ce:GdYAG ceramic phosphors with different Gd3+ contents were successfully prepared by the solid-state reaction method. The absorption and emission properties were investigated at different temperatures. The highest luminous efficiency of 123.7 lm/W was obtained by Ce:YAG ceramic phosphor with the thickness of 1 mm. The addition of Gd3+ results in red-shift and broadening of the emission band of Ce3+ so that the color rendering index (CRI) increases and the correlated color temperature (CCT) decreases obviously after packaged with blue light-emitting diode (LED). The color coordinates of the Ce:GdYAG ceramic phosphor with 50% Gd3+ content based white light device are located at the theoretical white light point in the CIE-1931 chromaticity diagram. And the various CRI and adjustable CCT of warm white light emitted by this device and the high luminous efficiency make Ce:GdYAG ceramics the most promising candidate for high-brightness white LEDs and laser diodes(LDs) device.