Cation Dynamics and Structural Stabilization in Formamidinium Lead Iodide Perovskites

The vibrational dynamics of pure and methylammonium-doped formamidinium lead iodide perovskites (FAPbI3) has been investigated by high-resolution neutron spectroscopy. For the first time, we provide an exhaustive and accurate analysis of the cation vibrations and underlying local structure around the organic moiety in these materials using first-principles electronic-structure calculations validated by the neutron data. Inelastic neutron scattering experiments on FAPbI3 provide direct evidence of the formation of a low-temperature orientational glass, unveiling the physicochemical origin of phase metastability in the tetragonal structure. Further analysis of these data provides a suitable starting point to explore and understand the stabilization of the perovskite framework via doping with small amounts of organic cations. In particular, we find that the hydrogen-bonding interactions around the formamidinium cations are strengthened as a result of cage deformation. This synergistic effect across perovskite cages is accompanied by a concomitant weakening of the methylammonium interactions with the surrounding framework.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:12

Enthalten in:

The journal of physical chemistry letters - 12(2021), 14 vom: 15. Apr., Seite 3503-3508

Sprache:

Englisch

Beteiligte Personen:

Drużbicki, Kacper [VerfasserIn]
Lavén, Rasmus [VerfasserIn]
Armstrong, Jeff [VerfasserIn]
Malavasi, Lorenzo [VerfasserIn]
Fernandez-Alonso, Felix [VerfasserIn]
Karlsson, Maths [VerfasserIn]

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Volltext

Themen:

Journal Article

Anmerkungen:

Date Revised 15.04.2021

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acs.jpclett.1c00616

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM323479707