4.8 Article

Strongly Anharmonic Octahedral Tilting in Two-Dimensional Hybrid Halide Perovskites

Journal

ACS NANO
Volume 15, Issue 6, Pages 10153-10162

Publisher

AMER CHEMICAL SOC
DOI: 10.1021/acsnano.1c02022

Keywords

2D perovskites; polarization-orientation; Raman; anharmonicity; phase transition; octahedral tilt; (C4H9NH3)(2)PbI4

Funding

  1. ISF [1861/17]
  2. BSF [2016650]
  3. ERC [850041]
  4. US National Science Foundation [DMR-1719353]
  5. Office of Naval Research [N00014-20-1-2701]
  6. Direct For Computer & Info Scie & Enginr
  7. Division Of Computer and Network Systems [2016650] Funding Source: National Science Foundation
  8. European Research Council (ERC) [850041] Funding Source: European Research Council (ERC)

Ask authors/readers for more resources

Recent studies have shown that the optical and electronic properties of 2D hybrid organic-inorganic halide perovskites are strongly influenced by thermal fluctuations. By comparing the structural dynamics of 3D and 2D crystals, the impact of organic cations on the inorganic scaffold can be revealed, providing insights into the performance of these materials.
Recent investigations of two-dimensional (2D) hybrid organic-inorganic halide perovskites (HHPs) indicate that their optical and electronic properties are dominated by strong coupling to thermal fluctuations. While the optical properties of 2D-HHPs have been extensively studied, a comprehensive understanding of electron-phonon interactions is limited because little is known about their structural dynamics. This is partially because the unit cells of 2D-HHPs contain many atoms. Therefore, the thermal fluctuations are complex and difficult to elucidate in detail. To overcome this challenge, we use polarization-orientation Raman spectroscopy and ab initio calculations to compare the structural dynamics of the prototypical 2D-HHPs [(BA)(2)PbI4 and (PhE)(2)PbI4] to their three-dimensional (3D) counterpart, MAPbI(3). Comparison to the simpler, 3D MAPBI(3) crystal shows clear similarities with the structural dynamics of (BA)(2)PbI4 and (PhE)(2)PbI4 across a wide temperature range. The analogy between the 3D and 2D crystals allows us to isolate the effect of the organic cation on the structural dynamics of the inorganic scaffold of the 2D-HHPs. Furthermore, using this approach, we uncover the mechanism of the order-disorder phase transition of (BA)(2)PbI4 (274 K) and show that it involves relaxation of octahedral tilting coupled to anharmonic thermal fluctuations. These anharmonic fluctuations are important because they induce charge carrier localization and affect the optoelectronic performance of these materials.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.8
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available