Structural and fluorescence features of Dy³⁺:Y₄Al₂O₉ phosphors for yellow color emitting displays

In this work, various concentrations (0.5, 1, 2, 3 and 4 at.%) of Dy³⁺-doped Y₄Al₂O₉ (YAM) phosphors have been synthesized using a high-temperature solid-state reaction method. For all phosphors, Dy ions optical absorption peaks intensity increases gradually with an increment in concentration, and a strong peak identified at 447 nm suggests that these phosphors can be efficiently pumped under a blue laser diode (LD) excitation. Upon 349 and 447 nm excitation, all samples show a prominent emission peak at 572 nm, which corresponds to Dy³⁺: ⁴F_9/2 → ⁶H_13/2 transition. Concentration quenching was observed for 1% Dy³⁺-doping under the excitation of 447 nm. All the measured fluorescence decay curves exhibit an exponential nature. The Commission International de L'Eclairagethe (CIE) chromaticity coordinates were calculated and they indicate the yellow color region in CIE diagram. The energy transfer (ET) processes between Dy³⁺ ions were discussed to explain the luminescence concentration quenching phenomena. Especially, 1 at. % Dy³⁺-doped YAM phosphor could be a potential candidate for yellow color emitting displays application.