Deep-red to near-infrared luminescence from Eu<sup>2+</sup>-trapped exciton states in YSiO<sub>2</sub>N
Deep-red to near-infrared luminescence from Eu<sup>2+</sup>-trapped exciton states in YSiO<sub>2</sub>N
复制标题
YSiO<sub>2</sub>N 中 Eu<sup>2 </sup> 俘获激子态的深红至近红外发光
DOI：
10.1039/d1cp05242j
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发表时间：
2022
影响因子：
3.3
通讯作者：
Tanabe Setsuhisa
中科院分区：
文献类型：
--
作者：
Kitagawa Yuuki;Ueda Jumpei;Xu Jian;Nakanishi Takayuki;Takeda Takashi;Hirosaki Naoto;Tanabe Setsuhisa
无机化合物中Eu离子的价态易受合成条件的影响。在这项研究中，X射线吸收光谱显示，几乎一半的Eu离子纳入YSiO 2N主机被还原成二价状态，通过烧结过程中，在1600 °C下，在氮气气氛下，没有任何退火过程。制备的Eu 2 +/3+掺杂YSiO 2N样品在300 K以下的紫光照射下表现出异常的深红色至近红外发光，通过详细的光谱分析对其发光特性进行了讨论。在4 K的光致发光光谱中，观察到550 - 1100 nm的宽发光带，其斯托克斯位移为5677 cm-1，归属于与Eu 2+捕获的激子态相关的复合发光。发光寿命的温度依赖性表明，热猝灭的Eu 2+捕获的激子发光发生通过复杂的过程，除了热电离。基于光谱结果的能量图表明，在YSiO 2N：Eu 2 +/3+样品中观察到了Eu 2+陷阱激子发光，这是因为所有的Eu 2+：5d激发能级都随基质导带简并，并且在导带底下方形成了相对稳定的Eu 2+陷阱激子态。对YSiO 2N基质中的深红色至近红外发光进行全面的讨论，可以对Eu 2+在Y3+位的捕获激子发光机制提供新的见解，这在近红外发光器件中具有潜在的应用前景。
The valence state of Eu ions doped in inorganic compounds is easily influenced by the synthesizing conditions. In this study, X-ray absorption spectroscopy revealed that almost half of Eu ions incorporated in the YSiO2N host were reduced into the divalent state through the sintering process at 1600 °C under a N2 gas atmosphere without any annealing processes. The prepared Eu2+/3+-doped YSiO2N sample showed anomalous deep-red to near-infrared luminescence below 300 K under violet light illumination, whose luminescent properties are discussed through detailed spectroscopic analyses. In the photoluminescence spectra at 4 K, the broad luminescence band ranging from 550 to 1100 nm with a large Stokes shift of 5677 cm−1 was observed, assigned to the recombination emission related to the Eu2+-trapped exciton state. The temperature dependence of luminescence lifetime suggests that the thermal quenching of Eu2+-trapped exciton luminescence takes place through complicated processes in addition to thermal ionization. The energy diagrams based on the spectroscopic results indicate that Eu2+-trapped exciton luminescence in the YSiO2N:Eu2+/3+ sample was observed because all the Eu2+: 5d excited levels are degenerated with the host conduction band, and the relatively stable Eu2+-trapped exciton state in the Y3+ sites is formed just below the conduction band bottom. A comprehensive discussion on the deep-red to near-infrared luminescence in the YSiO2N host could give new insights into the mechanism of Eu2+-trapped exciton luminescence in Y3+ sites, which has potential in near-infrared emitting devices.