Weak magnetic field-dependent photoluminescence properties of lead bromide perovskites
Weak magnetic field-dependent photoluminescence properties of lead bromide perovskites
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DOI：
10.1063/5.0085947
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发表时间：
2022-03
影响因子：
3.2
通讯作者：
Rory Butler;Randy Burns;Dallar Babaian;M.J. Anderson;C. Ullrich;Maria V. Morrell;Y. Xing;Jaewon L
中科院分区：
文献类型：
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作者：
Rory Butler;Randy Burns;Dallar Babaian;M.J. Anderson;C. Ullrich;Maria V. Morrell;Y. Xing;Jaewon L
当反转对称性被提升时，卤化铅钙钛矿中的强自旋轨道耦合（SOC）为研究这些系统中的Rashba效应提供了机会。此外，强的轨道矩，这反过来又影响了单重态和三重态电子状态的自旋对，在增强卤化铅钙钛矿中存在外部磁场时的光电性能方面起着重要作用。在这里，我们研究了弱磁场（<1 T）对光致发光（PL）特性的影响[公式：见正文]具有和不具有Ruddlesden-Popper（RP）故障的纳米晶体和[公式：见正文]的单晶。沿着作为外部磁场的函数的PL强度的增强，这在两种溴化铅钙钛矿中都观察到，[式：见正文]纳米晶体中的PL发射红移。[公式：见正文]中电子带边的密度泛函理论计算表明，作为外部磁场的函数，能隙几乎没有变化。因此，实验结果表明，在弱磁场下的三重态和单重态激子的混合的作用。这是进一步推导出在PL寿命的增强作为一个功能的领域[公式：见文字]。在[公式：在弱磁场下观察到PL强度的增加;然而，没有观察到峰值能量或PL寿命的变化。由于SOC的内部磁场的特点是所有三个样品，并发现是最高的[公式：见正文]纳米晶体与RP故障。
The strong spin–orbit coupling (SOC) in lead halide perovskites, when inversion symmetry is lifted, has provided opportunities for investigating the Rashba effect in these systems. Moreover, the strong orbital moment, which, in turn, impacts the spin-pair in singlet and triplet electronic states, plays a significant role in enhancing the optoelectronic properties in the presence of external magnetic fields in lead halide perovskites. Here, we investigate the effect of weak magnetic fields (<1 T) on the photoluminescence (PL) properties of [Formula: see text] nanocrystals with and without Ruddlesden–Popper (RP) faults and single crystals of [Formula: see text]. Along with an enhancement in the PL intensity as a function of an external magnetic field, which is observed in both lead bromide perovskites, the PL emission red-shifts in [Formula: see text] nanocrystals. Density-functional theory calculations of the electronic band-edge in [Formula: see text] show almost no change in the energy gap as a function of the external magnetic field. The experimental results, thus, suggest the role of mixing of the triplet and singlet excitonic states under weak magnetic fields. This is further deduced from an enhancement in PL lifetimes as a function of the field in [Formula: see text]. In [Formula: see text], an increase in PL intensity is observed under weak magnetic fields; however, no changes in the peak energy or PL lifetimes are observed. The internal magnetic fields due to SOC are characterized for all three samples and found to be the highest for [Formula: see text] nanocrystals with RP faults.