Tuning Spin-Polarized Lifetime in Two-Dimensional Metal-Halide Perovskite through Exciton Binding Energy

Xihan Chen, Haipeng Lu, Kang Wang, Yaxin Zhai, Vladimir Lunin, Peter Sercel, Matthew Beard

Research output: Contribution to journalArticlepeer-review

56 Scopus Citations

Abstract

Metal-halide perovskite semiconductors have attracted attention for opto-spintronic applications where the manipulation of charge and spin degrees of freedom have the potential to lower power consumption and achieve faster switching times for electronic devices. Lower-dimensional perovskites are of particular interest since the lower degree of symmetry of the metal-halide connected octahedra and the large spin-orbit coupling can potentially lift the spin degeneracy. To achieve their full application potential, long spin-polarized lifetimes and an understanding of spin-relaxation in these systems are needed. Here, we report an intriguing spin-selective excitation of excitons in a series of 2D lead iodide perovskite (n = 1) single crystals by using time- and polarization-resolved transient reflection spectroscopy. Exciton spin relaxation times as long as ∼26 ps at low excitation densities and at room temperature were achieved for a system with small binding energy, 2D EOA2PbI4 (EOA = ethanolamine). By tuning the excitation density and the exciton binding energy, we identify the dominant mechanism as the D'yakonov-Perel (DP) mechanism at low exciton densities and the Bir-Aronov-Pikus (BAP) mechanism at high excitation densities. Together, these results provide new design principles to achieve long spin lifetimes in metal-halide perovskite semiconductors.

Original languageAmerican English
Pages (from-to)19438-19445
Number of pages8
JournalJournal of the American Chemical Society
Volume143
Issue number46
DOIs
StatePublished - 24 Nov 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-80653

Keywords

  • exciton binding energy
  • metal-halide perovskite
  • spin coherence lifetimes

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