Kopteva Natalia E, Yakovlev Dmitri R, Kirstein Erik, Zhukov Evgeny A, Kudlacik Dennis, Kalitukha Ina V, Sapega Victor F, Hordiichuk Oleh, Dirin Dmitry N, Kovalenko Maksym V, Baumann Andreas, Höcker Julian, Dyakonov Vladimir, Crooker Scott A, Bayer Manfred
Experimentelle Physik 2, Technische Universität Dortmund, 44227, Dortmund, Germany.
Ioffe Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russia.
Small. 2024 Apr;20(16):e2300935. doi: 10.1002/smll.202300935. Epub 2023 Nov 27.
The optical properties of lead halide perovskite semiconductors in vicinity of the bandgap are controlled by excitons, so that investigation of their fundamental properties is of critical importance. The exciton Landé or g-factor g is the key parameter, determining the exciton Zeeman spin splitting in magnetic fields. The exciton, electron, and hole carrier g-factors provide information on the band structure, including its anisotropy, and the parameters contributing to the electron and hole effective masses. Here, g is measured by reflectivity in magnetic fields up to 60 T for lead halide perovskite crystals. The materials band gap energies at a liquid helium temperature vary widely across the visible spectral range from 1.520 up to 3.213 eV in hybrid organic-inorganic and fully inorganic perovskites with different cations and halogens: FACsPbIBr, MAPbI, FAPbBr, CsPbBr, and MAPb(BrCl). The exciton g-factors are found to be nearly constant, ranging from +2.3 to +2.7. Thus, the strong dependences of the electron and hole g-factors on the bandgap roughly compensate each other when combining to the exciton g-factor. The same is true for the anisotropies of the carrier g-factors, resulting in a nearly isotropic exciton g-factor. The experimental data are compared favorably with model calculation results.
卤化铅钙钛矿半导体在带隙附近的光学性质由激子控制，因此对其基本性质的研究至关重要。激子朗德或g因子g是关键参数，决定了磁场中激子的塞曼自旋分裂。激子、电子和空穴载流子的g因子提供了关于能带结构的信息，包括其各向异性以及对电子和空穴有效质量有贡献的参数。在此，通过对卤化铅钙钛矿晶体在高达60 T的磁场中的反射率来测量g。在液氦温度下，具有不同阳离子和卤素的混合有机-无机和全无机钙钛矿（FACsPbIBr、MAPbI、FAPbBr、CsPbBr和MAPb(BrCl)）的材料带隙能量在1.520至3.213 eV的可见光谱范围内变化很大。发现激子g因子几乎恒定，范围从+2.3到+2.7。因此，电子和空穴g因子对带隙的强烈依赖性在组合成激子g因子时大致相互补偿。载流子g因子的各向异性情况也是如此，导致激子g因子几乎是各向同性的。实验数据与模型计算结果吻合良好。
