Improving Crystallinity and Out-of-Plane Orientation in Quasi-2D Ruddlesden-Popper Perovskite by Fluorinated Organic Salt for Light-Emitting Diodes

Bingchen He, Tanghao Liu, Chenyue Wang, Zhaorui Wen, Bo Sun, Wen Wen, Guichuan Xing, Xingyu Gao*, Shi Chen*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

1 Citation (Scopus)

Abstract

Fluoro-substituted aromatic alkylammonium spacer cations are found effective to improve the performance of quasi-2D perovskite light-emitting diodes (PeLEDs). The fluorine substitution is generally attributed to the defect passivation, quantum well width control, and energy level adjustments. However, the substituted cations can also affect the crystallization process but is not thoroughly studied. Herein, a comparison study is carried out using bare PEA cation and three different fluoro-substituted PEA (x-F-PEA, x = o, ortho; m, meta; p, para) cations to investigate the impacts of different substitution sites on the perovskite crystallization and orientations. By using GIWAXS, p-F-PEA cation is found to induce the strongest preferential out-of-plane orientations with the best crystallinity in quasi-2D perovskite. Using dynamic light scattering (DLS) methods, larger colloidal particles (630 nm) are revealed in p-F-PEA precursor solutions than the PEA cations (350 nm). The larger particles can accelerate the crystallization process and induce out-of-plane orientation from increased dipole–dipole interaction. The transient absorption measurement confirms longer radiative recombination lifetime, proving beneficial effect of p-F-PEA cation. As a result, the fabricated p-F-PEA-based PeLEDs achieved the highest EQE of 15.2%, which is higher than those of PEA- (8.8%), o-F-PEA- (4.3%), and m-F-PEA-based (10.3%) PeLEDs.

Original languageEnglish
Article number2303255
JournalSmall
Volume19
Issue number49
Early online date22 Aug 2023
DOIs
Publication statusPublished - 6 Dec 2023

Scopus Subject Areas

  • Biotechnology
  • Chemistry(all)
  • Biomaterials
  • Materials Science(all)
  • Engineering (miscellaneous)

User-Defined Keywords

  • fluorinated organic salt
  • out-of-plane orientation
  • quasi-2D perovskite light-emitting diodes

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