Conjugated Polyelectrolytes as Multifunctional Passivating and Hole-Transporting Layers for Efficient Perovskite Light-Emitting Diodes

Seungjin Lee, Chung Hyeon Jang, Thanh Luan Nguyen, Su Hwan Kim, Kyung Min Lee, Kiseok Chang, Su Seok Choi, Sang Kyu Kwak, Han Young Woo, Myoung Hoon Song

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Metal halide perovskites (MHPs) have attracted significant attention as light-emitting materials owing to their high color purities and tunabilities. A key issue in perovskite light-emitting diodes (PeLEDs) is the fabrication of an optimal charge transport layer (CTL), which has desirable energy levels for efficient charge injection while blocking opposite charges and enabling perovskite layer growth with reduced interfacial defects. Herein, two poly(fluorene-phenylene)-based anionic conjugated polyelectrolytes (CPEs) with different counterions (K+ and tetramethylammonium (TMA+)) are presented as multifunctional passivating and hole-transporting layers (HTLs). The crystal growth of MHPs grown on different HTLs is investigated through X-ray photoelectron spectroscopy, X-ray diffraction, and density functional theory calculation. The CPE bearing the TMA+ counterions remarkably improves the growth of perovskites with suppressed interfacial defects, leading to significantly enhanced emission properties and device performance. The luminescent properties are further enhanced via aging and electrical stress application with effective rearrangement of the counterions on the interfacial defects in the perovskites. Finally, efficient formamidinium lead tribromide-based quasi-2D PeLEDs with an external quantum efficiency of 10.2% are fabricated. Using CPEs with varying counterions as a CTL can serve as an effective method for controlling the interfacial defects and improving perovskite-based optoelectronic device properties.

Original languageEnglish
Article number1900067
JournalAdvanced Materials
Volume31
Issue number24
DOIs
Publication statusPublished - 2019 Jun 13

Keywords

  • conjugated polyelectrolytes
  • defects
  • hole-transporting layers
  • passivation
  • perovskite light-emitting diodes

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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