High thermal stability phosphor: Red-emitting LiBaPO4:Sm3+

• LiBaPO4:Sm3+ phosphors were successfully synthesized via microwave-assisted sintering.
• The concentration quenching effect occurred when the concentration of Sm3+ ions is x = 0.05.
• The thermal quenching temperature T50 of LiBaPO4:Sm3+ phosphor was found to be 500 °C.
• LiBaPO4:Sm3+ phosphor exhibits better thermal stability than commercial YAG phosphor.

LiBa1 − xPO4:xSm3+ phosphors with various concentrations of Sm3+ ions (x = 0.01, 0.03, 0.05, 0.07 and 0.09) were successfully synthesized via microwave-assisted sintering at 900 °C for 3 h under an air atmosphere. The concentration quenching effect occurred when the concentration of Sm3+ ions is x = 0.05. The thermal quenching temperature T50 was found to be 500 °C, which is higher than that of the commercial YAG phosphor. The high activation energy ΔE of the LiBa0.95PO4:0.05Sm3+ phosphor was calculated to be 0.6 eV. Increasing Sm3+ ions gradually decreased the lifetime of the Sm3+ ions from 3.13 to 2.95 ms. All the chromaticity (x, y) of the prepared LiBa1 − xPO4:xSm3+ phosphors are located in the red region (0.57, 0.41). Moreover, the electroluminescence intensities increase as the current increases from 350 to 600 mA, indicating that LiBa0.95PO4:0.05Sm3+ phosphor prepared by microwave-assisted sintering exhibits excellent thermal stability, making it suitable for use as luminescent material for WLEDs.

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