High-Pressure Photoluminescence Properties of Cr<sup>3+</sup>-Doped LaGaO<sub>3</sub> Perovskites Modulated by Pressure-Induced Phase Transition
High-Pressure Photoluminescence Properties of Cr<sup>3+</sup>-Doped LaGaO<sub>3</sub> Perovskites Modulated by Pressure-Induced Phase Transition
复制标题
压力诱导相变调控Cr<sup>3</sup>掺杂LaGaO<sub>3</sub>钙钛矿的高压光致发光性能
DOI：
10.1021/acs.inorgchem.1c03074
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发表时间：
2021
影响因子：
4.6
通讯作者：
Tanabe Setsuhisa
中科院分区：
文献类型：
--
作者：
Hua Hansen;Ueda Jumpei;Xu Jian;Back Michele;Tanabe Setsuhisa
采用高压光谱法研究了Cr 3+掺杂LaGaO 3钙钛矿的光致发光特性。通过拉曼光谱证实了在2 GPa压力下从正交晶系（Pbnm）到菱方晶系（R3 ε c）的压致相变。掺Cr的LaGaO 3晶体在730 nm附近出现了由零声子线（R线）和声子边带组成的深红色发光峰，对应于理想八面体位置的Cr 3+：2 Eg → 4A 2g跃迁和环境条件下的Cr-Cr对发光（N线）。在高压下，R线以−13 cm-1/GPa的速率向较低的能量移动。从光致发光激发谱的压力依赖性出发，提出了R线红移是由Racah参数BandC的减小引起的。此外，随着压力的增加，N线发光相对于R线发光变得更强，N线/R线可以用来监测相变压力。在高压下，GaO 6八面体单元的倾斜角变小。这表明，N线发光增强是由于Cr-O-Cr键角增大到接近180°，Cr ~（3+）离子间的超交换作用增强所致。
The photoluminescence properties of Cr3+-doped LaGaO3perovskites are investigated by high-pressure spectroscopy. The pressure-induced phase transition from orthorhombic (Pbnm) to rhombohedral (R3̅c) at around 2 GPa is confirmed by Raman spectroscopy. Cr3+-doped LaGaO3shows deep-red emission peaks around 730 nm due to the zero-phonon line (R-line) and the phonon sidebands, which correspond to Cr3+:2Eg→4A2g transitions in the ideal octahedral site and the Cr–Cr pair luminescence (N-line) under ambient condition. Under a high pressure, theR-line shifts to a lower energy at a rate of −13 cm–1/GPa. From the pressure dependence of photoluminescence excitation (PLE) spectra, it is suggested that the redshift of theR-line is caused by the decrease of Racah parametersBandC. Moreover, theN-line luminescence becomes stronger relative to theR-line with increasing pressure and theN-line/R-line can be used to monitor the phase transition pressure. Under a high pressure, the tilt angle of the GaO6octahedral unit becomes smaller. It implies that the enhancedN-line luminescence is caused by the stronger superexchange interaction between Cr3+ions due to the increased Cr–O–Cr bond angle closer to 180°.