Strain modulated luminescence in (Ca,Sr)TiO3:Pr3+ perovskite thin films
Strain modulated luminescence in (Ca,Sr)TiO3:Pr3+ perovskite thin films
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DOI：
10.1016/j.jlumin.2021.118492
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发表时间：
2022-01
影响因子：
3.6
通讯作者：
Y. Katayama;K. Ueno
中科院分区：
文献类型：
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作者：
Y. Katayama;K. Ueno
报道了面内应变对钙钛矿荧光体薄膜光致发光特性的影响。采用脉冲激光沉积法在LaAlO 3（LAO，a= 3.815 μ m）、（LaAlO 3）0.3-（SrAl0.5Ta0.5O3）0.7（LSAT，3.868 μ m）和SrTiO 3（STO，3.905 μ m）三种不同晶格常数的钙钛矿氧化物衬底上制备了Ca0.6Sr0.4TiO3：Pr 3+荧光粉的钙钛矿外延薄膜。从X射线衍射，在LAO，LSAT和STO衬底上的薄膜的晶格常数分别为（a，c）=（3.815 μ m，3.956 μ m），（3.871 μ m，3.880 μ m）和（3.905 μ m，3.865 μ m）。因此，可以确认，在LAO、LSAT和STO衬底上分别获得了压缩应变（104%）、几乎无应变和拉伸应变（101%）的膜。在高于薄膜带隙能量的337 nm N2激光激发下，STO（tensile-strained）和LSAT（strain-free）衬底上的CSTO薄膜在300 K下均显示出强的红光发射，峰值位于612 nm，这是由于Pr 3+：1D 2 → 3 H4跃迁所致，而没有观察到3 P的光致发光谱线。而LAO（压应变）上的荧光膜在200 K以下出现了Pr 3+：3 P0能级跃迁的蓝光和红光。这些结果表明，在Pr 3+掺杂的钙钛矿荧光体薄膜中，光致发光的初始态可以通过双轴应变而不是通过组分从1D 2能级调谐到3 P0能级。用简化的四能级模型解释了光致发光的温度依赖性，载流子俘获中心可能与Ti中心有关。
We report in-plane strain effect on the photoluminescence property of perovskite phosphor thin films. Epitaxial perovskite thin films of Ca0.6Sr0.4TiO3:Pr3+phosphor were prepared on perovskite oxide substrates with different lattice constanta, LaAlO3(LAO,a= 3.815 Å), (LaAlO3)0.3-(SrAl0.5Ta0.5O3)0.7(LSAT, 3.868 Å), and SrTiO3(STO, 3.905 Å) by a pulsed laser deposition method. From X-ray diffraction, the lattice constants of thin films on LAO, LSAT, and STO substrates were (a, c) = (3.815 Å, 3.956 Å), (3.871 Å, 3.880 Å), and (3.905 Å, 3.865 Å), respectively. Therefore it was confirmed that compressive-strained (∼4%), nearly strain-free, and tensile-strained (∼1%) films were obtained on the LAO, LSAT and STO substrates, respectively. Under N2laser excitation at 337 nm which is above bandgap energy of thin films, the CSTO film on STO (tensile-strained) and on LSAT (strain-free) substrate showed intense red photoluminescence peaking at 612 nm due to Pr3+:1D2→3H4transition and no photoluminescence lines from the3PJrevels were observed at 300 K. On the other hand, the phosphor film on LAO (compressive-strained) showed blue and red luminescence which ascribed to the transitions from the Pr3+:3P0level below 200 K. These results showed that initial state of photoluminescence can be tuned from the1D2level to the3P0level by biaxial strain not by composition in the Pr3+doped perovskite phosphor films. The temperature dependence of photoluminescence was also explained by simplified four-level-model with carrier-trapping-center probably related to Ti center.