Luminescence and Energy Transfer in Thin Films of SrGa2 S 4 : Ce
Luminescence and Energy Transfer in Thin Films of SrGa2 S 4 : Ce
复制标题
SrGa2 S 4 : Ce 薄膜中的发光和能量转移
DOI：
10.1149/1.1391748
复制
发表时间：
1999
影响因子：
3.9
通讯作者：
H. Kobayashi
中科院分区：
文献类型：
--
作者：
O. Djazovski;T. Mikami;K. Ohmi;Shosaku Tanaka;H. Kobayashi
在10 ~ 300 K温度范围内测量了未掺杂和Ce 3+激活的SrGa 2S 4薄膜的激发光谱和光致发光（PL）谱。未掺杂的膜显示出复杂的发射带，这似乎涉及从不同的缺陷态的发射。每个缺陷中心在不同的温度范围内影响复合动力学和发光光谱。在77 K，重组是由高度相关的缺陷中心产生强烈的红色发射带。在较高的温度下，热化效应降低了竞争缺陷中心的净捕获率，并且在室温下通过缺陷中心的复合产生了宽的发射带，其峰值在蓝色光谱区域。通过对SrGa 2S 4：Ce薄膜中PL发射的上升时间和衰减时间的测量，证明了缺陷中心与Ce 3+激活态之间的相互作用和能量交换.作为热化的结果，在室温下，能量转移到Ce 3+离子的效率增加，但以引入长余辉到活化剂衰变为代价。PL强度的温度依赖性的测量表明，在SrGa 2 S 4：Ce的能量转移的动力学模型相结合的方面的远程共振转移和间接热化从缺陷态与随后的再俘获在激活位点。此外，还讨论了可能的机制，这些机制可以解释所观察到的Ce 3+荧光衰减时间的浓度依赖性。报道了用二元气相低温沉积法制备SrGa 2S 4：Ce，Li荧光粉薄膜电致发光器件的初步结果。
Excitation and photoluminescence (PL) spectra of both nominally undoped and Ce 3+ -activated SrGa 2 S 4 thin films have been measured at various temperatures between 10 and 300 K. The undoped film shows a complex emission band which appears to involve emission from different defect states. Each defect center effects the recombination kinetics and luminescence spectra in a different temperature region. At 77 K, recombination is dominated by the highly associated defect centers producing an intense red emission band. At higher temperatures, thermalization effects reduce the net capture rates at the competitive defect centers, and recombination through the defect centers at room temperature produces a broad emission band with the peak in the blue spectral region. Evidence of the interaction and energy exchange between defect centers and Ce 3+ activator states is inferred from the rise and decay time measurements of PL emission in SrGa 2 S 4 :Ce thin films. As a result of thermalization, the efficiency of energy transfer to Ce 3+ ions increases at room temperature but at the expense of introducing a long afterglow into the activator decay. Measurements of temperature dependence of PL intensity suggest that the kinetic model for energy transfer in SrGa 2 S 4 :Ce combines aspects of long-range resonance transfer and indirect thermalization from defect states with subsequent retrapping at the activator sites. In addition, possible mechanisms are discussed which may explain the observed concentration dependence of the Ce 3+ fluorescence decay time. Preliminary results are reported for a thin-film electroluminescent device with a SrGa 2 S 4 :Ce, Li phosphor layer prepared by the low-temperature deposition from binary vapors process.