Studies of high-membered two-dimensional Ruddlesden-Popper Cs7Pb6I19 perovskite nanosheets via kinetically controlled reactions

Yi-Chia Chen; Kuan-Chang Wu; Hsin-An Chen; Wen-Hui Chu; Swathi M Gowdru; Jou-Chun Lin; Bi-Hsuan Lin; Mau-Tsu Tang; Chia-Che Chang; Ying-Huang Lai; Tsung-Rong Kuo; Cheng-Yen Wen; Di-Yan Wang

doi:10.1039/d2mh00539e

Studies of high-membered two-dimensional Ruddlesden-Popper Cs₇Pb₆I₁₉ perovskite nanosheets via kinetically controlled reactions

Mater Horiz. 2022 Aug 30;9(9):2433-2442. doi: 10.1039/d2mh00539e.

Authors

Affiliations

¹ Department of Chemistry, Tunghai University, Taichung 407224, Taiwan. diyanwang@thu.edu.tw.
² Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei, Taiwan.
³ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
⁴ Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan.
⁵ Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan.

PMID: 35848594
DOI: 10.1039/d2mh00539e

Abstract

Two-dimensional (2D) all-inorganic Ruddlesden-Popper (RP) perovskite Cs₇Pb₆I₁₉ nanosheets (NSs) were successfully developed for the first time by employing a structural recrystallization process with additional passivation of small organic sulfide molecules. The structure of Cs₇Pb₆I₁₉ NSs is confirmed by powder X-ray diffraction measurements, atomically-resolved STEM measurements and atomic force microscopy (AFM) studies. Cs₇Pb₆I₁₉ NSs with a specific n value of 6 exhibits unique absorption and emission spectra with intense excitons at 560 nm due to quantum confinement effects in 2D perovskite slabs. The formation mechanisms of 2D Cs₇Pb₆I₁₉ NSs and 3D γ-CsPbI₃ phases were investigated by in situ photoluminescence (PL) spectroscopy and the activation energies of their formation reactions were calculated to be 151 kJ mol^-1 and 95.3 kJ mol^-1, respectively. The phase stability of 2D Cs₇Pb₆I₁₉ NSs can be maintained at temperatures below 14 °C for more than 4 weeks. The overall results indicate that 2D Cs₇Pb₆I₁₉ NSs demonstrate unique optical properties and structural stability compared with other 3D perovskite materials. We have opened a new path to the future discovery of 2D perovskite structures with metastable phases by using this recrystallization method and the assistance of sulfur-derived organic molecules.