A novel yellowish white Dy³⁺ activated α-Al₂O₃ phosphor: Photoluminescence and optical studies

Trivalent Dy doped α- Al ₂ O ₃ phosphor was synthesized by low temperature solution combustion method using urea as fuel. The phosphor was well characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy and diffused reflectance spectroscopy (DRS). XRD study confirmed the hexagonal structure of Dy ³⁺ doped α- Al ₂ O ₃ as prepared phosphor. Under various ultraviolet (UV) excitations (353 nm, 367 nm and 325 nm), α- Al ₂ O ₃: Dy ³⁺ phosphor exhibits the characteristic emission bands centered at 490 nm, 589 nm and 670 nm, resulting from the ⁴ F _9/2–⁶ H _{J /2} ( J = 15, 13, 11) transitions of Dy ³⁺, respectively. The observed CIE coordinates (x, y) as (0.373, 0.379) corresponds to the shade of yellowish white in color gamut. The bandgap was calculated using diffused reflectance (DR) spectrum and it was estimated around 5.9 eV.