在单一临床二维混合酸罗夫斯基特中发射暗刺激
Aparna Shinde1, Parikshit Kumar Rajput1, Urmila Makhija1
1Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India.
Nano letters
|July 24, 2023
概括
研究人员观察到强烈的暗激子 (XD) 光辐射没有磁场在特定的单临床杂交矿. 这一发现为探索二维材料中的激子动态开辟了新的途径.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 光物理学的光学物理学
背景情况:
- 明亮刺激子 (XB) 通常在2D层混合矿中发射光.
- 暗刺激子 (XD) 具有旋转禁止的辐射重组,通常需要磁场发射.
- 了解激子的行为对于光电子应用至关重要.
研究的目的:
- 为了研究在没有磁场的情况下获得暗刺激子 (XD) 光辐射的可能性.
- 探索晶体对称性和温度对刺激子发射特性的影响.
主要方法:
- 在低温温度 (∼7K) 的光发光谱学.
- 合成和描述具有不同晶体对称性的混合矿材料 (单临床和正方形).
- 时间分辨率的光发光度测量,以确定刺激子的寿命.
主要成果:
- 异常强烈的XD辐射在单临床 (Rac-MBA)2PbI4, (Rac-4-Br-MBA)2PbI4,和 (R-4-Br-MBA)2PbI4中观察到约7K.
- 在类似的条件下,Orthorhombic (R-MBA) 2PbI4没有表现出显著的XD辐射.
- 在单临床样本中,XD和XB之间的很大的能量差异 (ΔE ∼ 20 meV) 抑制了XD到XB的热激发,低于30K.
- XD辐射呈现出长寿命 (∼205 ns),与XB辐射在更高温度下的短寿命 (<1 ns) 相反.
结论:
- 混合矿中的较低晶体对称性 (单临床) 可以促进强烈的,无场的暗激子发射.
- 暗和亮激子之间的能量分离在控制它们的辐射重组路径方面发挥着至关重要的作用.
- 这些发现为潜在的设备应用提供了在2D材料中操纵激子动态的新策略.
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