Jeong M J, Lee S W, Wi S W, Lee K C, Lee Y S
Department of Physics and Integrative Institute of Basic Sciences, Soongsil University, Seoul, 06978, Republic of Korea.
Heliyon. 2023 Sep 9;9(9):e20006. doi: 10.1016/j.heliyon.2023.e20006. eCollection 2023 Sep.
We investigated the changes in the structural and luminescent properties of Eu-ion-doped ASiO (ASiO:Eu, A = Ba, Sr, and Ca) by annealing in oxidizing and reducing atmospheres. The initially synthesized samples displayed distinct, intense red emissions at approximately 600 and 700 nm, which can be attributed to the presence of Eu ions. The emission intensity of Eu was the strongest in CaSiO:Eu, which exhibited the lowest lattice symmetry among the three samples. Remarkably, following annealing in a reducing atmosphere (H), the previously observed red emission vanished, and instead, a strong green emission at around 500 nm, which is characteristic of Eu ions. Because of the two occupation sites of the Eu ions in ASiO, the emission of Eu strongly depends on the excitation wavelength, which is the most evident in CaSiO:Eu. Conversely, after annealing in an oxidizing atmosphere (O), the emission in the green region was suppressed and the emission in the red region returned. The reversible transition between two oxidation states occurred repeatedly by alternating H and O annealing, resulting in good color tunability in wide visible region with a simple ambient annealing process in a single compound.
我们通过在氧化和还原气氛中退火，研究了Eu离子掺杂的ASiO（ASiO:Eu，A = Ba、Sr和Ca）的结构和发光性质的变化。最初合成的样品在约600和700 nm处显示出明显的强红色发射，这可归因于Eu离子的存在。Eu的发射强度在CaSiO:Eu中最强，该样品在三个样品中表现出最低的晶格对称性。值得注意的是，在还原气氛（H）中退火后，先前观察到的红色发射消失，取而代之的是在约500 nm处的强绿色发射，这是Eu离子的特征。由于Eu离子在ASiO中有两个占据位点，Eu的发射强烈依赖于激发波长，这在CaSiO:Eu中最为明显。相反，在氧化气氛（O）中退火后，绿色区域的发射受到抑制，红色区域的发射恢复。通过交替进行H和O退火，两种氧化态之间的可逆转变反复发生，通过在单一化合物中进行简单的环境退火过程，在宽可见光区域实现了良好的颜色可调性。
