Novel Necklace-like MAl₂O₄:Eu²⁺, Dy³⁺ (M = Sr, Ba, Ca) Phosphors via a CTAB-Assisted Solution-Phase Synthesis and Postannealing Approach

We herein present a facile but efficient CTAB-assisted solution-phase synthesis and postannealing approach for preparing a series of necklace-like phosphors, including SrAl 2 O 4:Eu 2+, Dy 3+, CaAl 2 O 4:Eu 2+, Dy 3+, and BaAl 2 O 4:Eu 2+, Dy 3+ . The as-prepared samples were characterized by means of XRPD, FESEM, TEM, and PL techniques. The experimental results indicate that CTAB plays the crucial role in the formation of needle-like precursors in solution, which are further converted into the final phosphors in a reducing atmosphere of H 2 /Ar (15% + 85%). To investigate the optical characteristics of the aluminate phosphors, we conducted the excitation, emission, and afterglow decaying measurements at room temperature. It is noteworthy that the aluminate phosphors are so floppy after being calcined at 1300 °C for 5 h, which effectively avoids the traditional crushing of hard phosphor blocks into small particles.