Excitonic emissions and above-band-gap luminescence in the single-crystal perovskite semiconductors CsPbBr3 and CsPbCl3
Excitonic emissions and above-band-gap luminescence in the single-crystal perovskite semiconductors CsPbBr3 and CsPbCl3
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DOI：
10.1103/physrevb.92.235210
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发表时间：
2015-12-29
影响因子：
3.7
通讯作者：
Wessels, B. W.
中科院分区：
文献类型：
--
作者：
Sebastian, M.;Peters, J. A.;Wessels, B. W.
三元化合物CsPbX3（X = Br或Cl）具有钙钛矿结构，正被考虑用于光学和电子应用，如激光和伽马射线检测。在这两种CsPbX3化合物中均观察到带隙以上的激子光致发光（PL）带。一个激子发射峰中心在2.98 eV，类似于0.1 eV以上的室温带隙，观察CsPbCl 3。激子发光的热猝灭是很好地描述了一个两步猝灭模型，产生的激活能为0.057和0.0076 eV的高，低温制度，分别。CsPbBr3具有位于2.29和2.33 eV的束缚激子发光峰，其归因于涉及Br空位中心的复合。计算了CsPbBr3的激子发光的热猝灭活化能为0.017和0.0007 eV。温度依赖性PL实验揭示了CsPbX3化合物中所有激子发射峰的意外蓝移。声子辅助的升压过程导致CsPbBr 3发射的蓝移，而CsPbCl 3的带隙加宽也有贡献。在这些化合物中没有显著的深能级缺陷发光使它们成为高分辨率、室温辐射检测的有吸引力的候选者。
The ternary compounds CsPbX3 (X = Br or Cl) have perovskite structures that are being considered for optical and electronic applications such as lasing and gamma-ray detection. An above-band-gap excitonic photoluminescence (PL) band is seen in both CsPbX3 compounds. An excitonic emission peak centered at 2.98 eV, similar to 0.1 eV above the room-temperature band gap, is observed for CsPbCl3. The thermal quenching of the excitonic luminescence is well described by a two-step quenching model, yielding activation energies of 0.057 and 0.0076 eV for high-and low-temperature regimes, respectively. CsPbBr3 exhibits bound excitonic luminescence peaks located at 2.29 and 2.33 eV that are attributed to recombination involving Br vacancy centers. Activation energies for thermal quenching of the excitonic luminescence of 0.017 and 0.0007 eV were calculated for CsPbBr3. Temperature-dependent PL experiments reveal unexpected blueshifts for all excitonic emission peaks in CsPbX3 compounds. A phonon-assisted step-up process leads to the blueshift in CsPbBr3 emission, while there is a contribution from band-gap widening in CsPbCl3. The absence of significant deep level defect luminescence in these compounds makes them attractive candidates for high-resolution, room-temperature radiation detection.