Lead-Dominated Hyperfine Interaction Impacting the Carrier Spin Dynamics in Halide Perovskites.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34606138.
- Also identified by DOI 10.1002/adma.202105263 and PMC identifier 11468769.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The outstanding optical quality of lead halide perovskites inspires studies of their potential for the optical control of carrier spins as pursued in other materials. Entering largely uncharted territory, time-resolved pump-probe Kerr rotation is used to explore the coherent spin dynamics of electrons and holes in bulk formamidinium caesium lead iodine bromide (FA<sub>0.9</sub> Cs<sub>0.1</sub> PbI<sub>2.8</sub> Br<sub>0.2</sub> ) and to determine key parameters characterizing interactions of their spins, such as the g-factors and relaxation times. The demonstrated long spin dynamics and narrow g-factor distribution prove the perovskites as promising competitors for conventional semiconductors in spintronics. The dynamic nuclear polarization via spin-oriented holes is realized and the identification of the lead (<sup>207</sup> Pb) isotope in optically detected nuclear magnetic resonance proves that the hole-nuclei interaction is dominated by the lead ions. A detailed theoretical analysis accounting for the specifics of the lead halide perovskite materials allows the evaluation of the underlying hyperfine interaction constants, both for electrons and holes. Recombination and spin dynamics evidence that at low temperatures, photogenerated electrons and holes are localized at different regions of the perovskite crystal, resulting in their long lifetimes up to 44 μs. The findings form the base for the tailored development of spin-optoelectronic applications for the large family of lead halide perovskites and their nanostructures.