Potential single phased full colour white light Sr2−xCeO4∶xSm3+ phosphor for UV light emitting diodes

Abstract

A potential single phased white Sr2CeO4∶Sm3+ phosphor was fabricated by a hydrothermal calcine method. The luminescence intensity of Sr2CeO4 host and redistribution depended on the doped Sm3+ concentration. It is also found that the photoluminescence spectrum exhibits a redshift when the Sm3+ concentration is increased from 0 to 2 mol-%. The phosphor can emit full colour white light with the Sm3+ concentration increasing from 0·5 to 1·0 mol-%. The energy transfer model is interpreted as the possible mechanisms of energy transfer from Sr2CeO4 host to Sm3+ in Sr2CeO4∶Sm3+ system. The fabrication and packaging of a white phosphor-converted light emitting diode (LED) by adopting a white Sr2CeO4∶Sm3+ phosphor with an ultraviolet (UV) LED chip with the wavelength of 350 nm is also successfully demonstrated. A white light with colour coordinates (0·3315, 0·3109) and luminescence efficiency of 56 lm W−1 could be obtained from the fabricated LEDs when keeping the Sr2−xCeO4∶xSm3+ phosphor doped with the content of Sm3+ at 1·0 mol-%, which shows that the phosphor is a promising single phase phosphor for UV LED.