Structural and photoluminescence properties of Dy³⁺ -activated NaCaPO₄ phosphor derived from solution combustion

In the current investigation, a series of NaCa_1-x PO₄ :xDy³⁺ (x = 0.1, 0.3, 0.5, 0.7, 1.0, 1.5 and 2 mol%) phosphors were synthesized using a solution combustion method and citric acid as fuel. The investigated results from the X-ray diffraction (XRD) pattern showed phase purity of the synthesized material and orthorhombic crystal structure with space group Pna21. Photoluminescence properties of the synthesized phosphors were investigated. The synthesized Dy³⁺ -activated phosphor displayed blue (482 nm) and yellow (576 nm) emission under near-ultraviolet or blue excitations. These emission bands were ascribed due to the ⁴ F_9/2 →⁶ H_15/2 and ⁴ F_9/2 →⁶ H_13/2 transitions of Dy³⁺ ions. Commission International de l'Eclairage chromaticity coordinates showed emission in the near-white region for the proposed phosphors under different excitations. In addition, the current-voltage (I-V) characteristics of the NaCa_1-x PO₄ :xDy³⁺ (x = 1.5 mol%) phosphor-coated silicon solar cell and an uncoated solar cell were investigated under a solar simulator. The I-V characteristics of the proposed phosphor-coated silicon solar cell showed enhancement in solar cell efficiency by ~7.92%. The entire studies and their outcomes showed that synthesized phosphors have potential as white light emitting diodes and for solar applications.