Kalita Manash, Kalita J M
Department of Physics, Cotton University, Guwahati, 781001, India.
J Fluoresc. 2025 May;35(5):3171-3180. doi: 10.1007/s10895-024-03759-w. Epub 2024 May 11.
We studied steady-state and time-resolved photoluminescence of Eu doped BaAlO phosphor. The undoped BaAlO sample shows a dominant blue emission band at ~ 428 nm and two secondary maxima at ~ 405 and 456 nm due to F-centre and aggregate defects such as F -centre. The samples after doping of Eu at 1-5% show additional emission bands at ~ 485 and 518 nm due to Eu centre and a red emission band at ~ 657 nm is attributed to Eu centre. The sample doped with 2% of Eu shows anomalous emission having the dominant peak at ~ 494 nm. The average luminescence lifetime of the emission band at ~ 428 nm in the undoped sample was estimated to be (3.29 ± 0.91) ns. The average luminescence lifetime of this emission band after doping of Eu was found to increase by 10 orders of magnitude. The intensity of the 428 nm blue emission band was found to quench after doping of Eu beyond 3%. The concentration quenching effect was attributed to dipole-quadrupole interaction. Further, a non-radiative fluorescence energy transfer mechanism from an extrinsic Eu centre to an intrinsic F-centre is proposed to describe the luminescence dynamics of the samples.
我们研究了铕掺杂的BaAlO荧光粉的稳态和时间分辨光致发光。未掺杂的BaAlO样品由于F中心和诸如F中心等聚集缺陷，在428nm处显示出一个占主导地位的蓝色发射带，在405和456nm处有两个次要最大值。在1-5%的铕掺杂后，样品由于铕中心在485和518nm处显示出额外的发射带，在657nm处的红色发射带归因于铕中心。掺杂2%铕的样品显示出异常发射，其主峰在494nm处。未掺杂样品中428nm发射带的平均发光寿命估计为(3.29±0.91)ns。铕掺杂后该发射带的平均发光寿命增加了10个数量级。发现铕掺杂超过3%后，428nm蓝色发射带的强度会猝灭。浓度猝灭效应归因于偶极-四极相互作用。此外，提出了一种从外在铕中心到内在F中心的非辐射荧光能量转移机制来描述样品的发光动力学。
