Reassignment of electronic transitions in the laser-activated spectrum of nanocrystalline Y2O3:Er3+
Reassignment of electronic transitions in the laser-activated spectrum of nanocrystalline Y2O3:Er3+
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DOI：
10.1016/j.jlumin.2017.12.053
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发表时间：
2018-04
影响因子：
3.6
通讯作者：
D. Engelsen;G. Fern;T. Ireland;J. Silver
中科院分区：
文献类型：
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作者：
D. Engelsen;G. Fern;T. Ireland;J. Silver
本文描述和分析了在不同温度和两种激发能量下记录的纳米晶Y_2O_3：Er ~（3+）的激光激活光谱。根据最近发表的Er ~（3+）在立方Y_2O_3晶格中的C_2型Stark分裂的修正值，对观测到的光谱中的Er ~（3+）多重态进行了重新归属。根据Arrhenius型分析，我们追踪了4S 3/2Kramers双重态的3个2 H11/2→ 4 I15/2热带的上转换路径。在2 H_（11/2）→ 4 I_（15/2）热带区观察到5个不同温度行为的峰。这些带属于2 P3/2→ 4 I9/2多重态，并且它们的偏离温度行为已根据交叉弛豫机制来解释。从在不同激发能量下记录的激光激活光谱之间的比率，我们得出结论，双光子吸收过程在增加激发能量时变得更有效。我们还对2 H_（11/2）→ 4 I_（15/2）多重峰的荧光谱带从518 nm逐渐展宽到542 nm的现象提出了解释。较高的斯塔克分裂能级是由于主晶格的较强静电场，因此经历较高的电子-声子相互作用，这解释了在较大波长处观察到的FWHM增加。
The laser-activated spectra of nanocrystalline Y2O3:Er3+recorded at various temperatures and two excitation energies are described and analysed herein. Based on recently published modified values of the C2-type Stark splitting of Er3+in the cubic Y2O3lattice, the Er3+multiplets in the observed spectra have been re-assigned. The upconversion routes of three2H11/2→4I15/2hot bands from4S3/2Kramers doublets have been traced, based on an Arrhenius-type analysis of these hot bands. We observed 5 peaks in the2H11/2→4I15/2hot band region with a different temperature behaviour. These bands belong to the2P3/2→4I9/2multiplet and their deviating temperature behaviour has been explained in terms of a cross relaxation mechanism. From the ratio between the laser-activated spectra that were recorded at different excitation energies we concluded that the two-photon absorption process becomes more efficient upon increasing the excitation energy. We have also put forward an explanation for the gradual broadening of the fluorescence bands of the2H11/2→4I15/2multiplet in going from 518 nm to 542 nm. The higher Stark splitting levels are due to a stronger electrostatic field of the host lattice and experience therefore a higher electron-phonon interaction, which explains the observed increase of FWHM at larger wavelengths.