Weak Dispersion of Exciton Landé Factor with Band Gap Energy in Lead Halide Perovskites: Approximate Compensation of the Electron and Hole Dependences
Abstract
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 Land & eacute; or g-factor g(X) 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(X) 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: FA(0.9)Cs(0.1)PbI(2.8)Br(0.2), MAPbI(3), FAPbBr(3), CsPbBr3, and MAPb(Br0.05Cl0.95)(3). 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. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000649555Publication status
publishedExternal links
Journal / series
SmallVolume
Pages / Article No.
Publisher
Wiley-VCHSubject
electron g-factor; exciton Lande factor; hole g-factor; lead halide perovskites; magneto-reflectivity; pump-probe Kerr ellipticity; spin-flip Raman scatteringOrganisational unit
03934 - Kovalenko, Maksym / Kovalenko, Maksym
Funding
186406 - Spin and recombination dynamics of excitons and carriers in metal halide perovskites (SNF)
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