Tunable Single-Phase White Light Emission from Complex Perovskite Sr3CaNb2O9: Dy3+/Eu3+ Phosphors

Sr 3 CaNb 2 O 9 :Dy 3+ /Eu 3+ phosphors with a complex perovskite structure are prepared using a high-temperature solid- state reaction technique. These phosphors are doped either singly or in combination with Dy 3+ /Eu 3+ ions, resulting in efficient energy transfer from Dy 3+ to Eu 3+ and thus tunable-color emission. Under 353 nm excitation, the Sr 3 CaNb 2 O 9 :Dy 3+ phosphor emits blue (492 nm), yellow (583 nm), and red (682 nm) light, with the optimal doping concentration of Dy 3+ of 0.04%. When excited by 394 nm ( 7 F 0 → 5 L 6 ), the Sr 3 CaNb 2 O 9 :Eu 3+ phosphor exhibits two most intense emissions centered at 593 nm ( 5 D 0 → 7 F 1 ) and 614 nm ( 5 D 0 → 7 F 2 ). The decrease in luminescence intensity with increasing doping concentration of Dy 3+ and Eu 3+ is due to the cross-relaxation associated with electric dipole–dipole interaction. Photoluminescence emission measurements under excitations of 353 and 365 nm indicate that the Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor shows excellent thermal stability, even at a temperature of 150 °C, where the luminescence intensity preserves 79% of its initial value at room temperature. The electroluminescence performance of the Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor is tested with 365 nm LED chips for potential use in white LEDs. The results confirm that Sr 3 CaNb 2 O 9 :0.04Dy 3+ /0.05Eu 3+ phosphor has great potential for use in high-power white LED applications as a single matrix.