Photo-excited charge carrier lifetime enhanced by slow cation molecular dynamics in lead iodide perovskite FAPbI3

Journal Article · 03 August 2023 · Journal of Applied Physics

DOI: https://doi.org/10.1063/5.0159708 · OSTI ID:2420469

Hiraishi, M.  ^[1]; Koda, A.; Okabe, H. ; Kadono, R. ; Dagnall, K. A.; Choi, J. J. ; Lee, S. -H.

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1. OSTI

Using muon spin relaxation measurements on formamidinium lead iodide [FAPbI3, where FA denotes HC(NH2)2], we show that, among the five structurally distinct phases of FAPbI3 exhibited through two different temperature hysteresis, the reorientation motion of FA molecules is quasi-static below ≈50 K over the time scale of 10−6 s in the low-temperature (LT) hexagonal (Hex-LT, <160 K) phase, which has a relatively longer photo-excited charge carrier lifetime (τc∼10−6 s). In contrast, a sharp increase in the FA molecular motion was found above ≈50 K in the Hex-LT phase, LT-tetragonal phase (Tet-LT, <140 K), the high-temperature (HT) hexagonal phase (Hex-HT, 160–380 K), and the HT-tetragonal phase (Tet-HT, 140–280 K), where τc decreases with increasing temperature. More interestingly, the reorientation motion is further promoted in the cubic phase at higher temperatures (>380/280 K), while τc is recovered to comparable or larger than that of the LT phases. These results indicate that there are two factors that determine τc, one related to the local reorientation of cationic molecules that is not unencumbered by phonons and the other to the high symmetry of the bulk crystal structure.

• Research Organization: Univ. of Virginia, Charlottesville, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC0016144
• OSTI ID: 2420469
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 5 Vol. 134; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English