Case Studies on Structure-Property Relations in Perovskite Light-Emitting Diodes via Interfacial Engineering with Self-Assembled Monolayers

Seo Yeon Kim, Hungu Kang, Kiseok Chang, Hyo Jae Yoon

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Metal halide perovskites promise bright and narrow-band light-emitting diodes (LEDs). To this end, reliable understanding on structure-property relations is necessary, yet singling out one effect from others is difficult because photophysical and electronic functions of perovskite LEDs are interwoven each other. To resolve this problem, we herein employ self-assembled monolayers (SAMs) for interfacial engineering nanomaterials. Four different molecules that have the same anchor (thiol), different backbone (aryl vs alkyl) and different terminal group (amine vs pyridine vs methyl) are used to form SAMs at the interface with the thin film of a green-color perovskite, CH3NH3PbBr3. SAM-engineered perovskite films are characterized with X-ray diffraction (XRD), depth-profile X-ray photoelectron spectroscopy (XPS), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM), time-resolved laser spectroscopy, and UV-vis absorption and emission spectroscopies. This permits access to how the chemical structure of molecule comprising SAM is related to the various chemical and physical features such as quality and grain size, cross-sectional atomic composition (Pb(0) vs Pb(II)), charge carrier lifetime, and charge mobility of perovskite films, leading to inferences of structure-property relations in the perovskite. Finally, we demonstrate that the trends observed in the model system stem from the affinity of SAM over the undercoordinated Pb ions of perovskite, and these are translated into considerably enhanced EQE (from 2.20 to 5.74%) and narrow-band performances (from 21.3 to 15.9 nm), without a noticeable wavelength shift in perovskite LEDs. Our work suggests that SAM-based interfacial engineering holds a promise for deciphering mechanisms of perovskite LEDs.

Original languageEnglish
Pages (from-to)31236-31247
Number of pages12
JournalACS Applied Materials and Interfaces
Volume13
Issue number26
DOIs
Publication statusPublished - 2021 Jul 7

Keywords

  • interface engineering
  • light emitting diodes (LEDs)
  • nanomaterials
  • perovskites
  • self-assembled monolayers (SAMs)

ASJC Scopus subject areas

  • Materials Science(all)

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