Polaron and Spin Dynamics in Organic–Inorganic Lead Halide Perovskite Nanocrystals. Issue 24 (23rd October 2020)

• Record Type: Journal Article
• Authors: Shrivastava, Megha; Bodnarchuk, Maryna I.; Hazarika, Abhijit; Luther, Joseph M.; Beard, Matthew C.; Kovalenko, Maksym V.; Adarsh, K. V.
• Is Part Of: Advanced optical materials. Volume 8:Issue 24(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-23
• Subjects: organic–inorganic lead halide perovskites -- polarons -- spin dynamics; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202001016
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Long‐lived carrier population and spin‐based behavior in lead halide perovskite nanocrystals (NCs) are extremely interesting for implementing photovoltaic devices with efficiencies exceeding the Shockley–Queisser limit and quantum information processing, respectively. However, a comprehensive understanding of polaron‐mediated charge carrier interactions and an accurate description of the spin‐polarized states for spintronics are still lacking. Herein, the carrier and spin interactions are studied under controlled conditions in FAPbI3 and Cs0.01 FA0.99 Pb(Br0.11 I0.89 )3 NCs through ultrafast transient absorption (TA) spectroscopy. At early timescales, TA spectrum shows an asymmetric derivative feature originating from the hot carrier‐induced spectral redshift in FAPbI3 NCs (55 ± 3 meV) and Cs0.01 FA0.99 Pb(Br0.11 I0.89 )3 NCs (54 ± 2 meV) at the bandedges that stabilizes to 9 ± 1 and 11 ± 2 meV, respectively, at 1 ps due to the polaron formation. The kinetic analysis indicates that the polaron populations in FAPbI3 and Cs0.01 FA0.99 Pb(Br0.11 I0.89 )3 NCs decay with an average lifetime of 657 ± 34 and 532 ± 28 ps, respectively. The circular polarization‐resolved TA reveals that polaron formation can control spin relaxation in NCs, thus providing a powerful tool to explore the development of their prospective applications in spintronics. Abstract : The strong carrier–phonon coupling and soft lattice of organic–inorganic lead halide perovskite (OILHP) nanocrystals enable the polaron formation, which dramatically modifies photophysics and carrier dynamics. Polaron‐mediated carrier protection and spin manipulation in OILHPs are demonstrated via composition tuning to develop next‐generation opto‐spintronics devices.