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Surface‐2D/Bulk‐3D Heterophased Perovskite Nanograins for Long‐Term‐Stable Light‐Emitting Diodes
Author(s) -
Han TaeHee,
Lee JinWook,
Choi Yung Ji,
Choi Chungseok,
Tan Shaun,
Lee SungJoon,
Zhao Yepin,
Huang Yu,
Kim Dongho,
Yang Yang
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201905674
Subject(s) - materials science , light emitting diode , electroluminescence , optoelectronics , perovskite (structure) , exciton , diode , charge carrier , halide , nanotechnology , chemical engineering , condensed matter physics , layer (electronics) , inorganic chemistry , chemistry , physics , engineering
Although metal halide perovskite (MHP) light‐emitting diodes (LEDs) have demonstrated great potential in terms of electroluminescence efficiency, the operational stability of MHP LEDs currently remains the biggest bottleneck toward their practical usage. Well‐confined excitons/charge carriers in a dielectric/quantum well based on conventional spatial or potential confinement approaches substantially enhance radiative recombination in MHPs, but an increased surface‐to‐volume ratio and multiphase interfaces likely result in a high degree of surface or interface defect states, which brings about a critical environmentally/operationally vulnerable point on LED stability. Here, an effective solution is suggested to mitigate such drawbacks using strategically designed surface‐2D/bulk‐3D heterophased MHP nanograins for long‐term‐stable LEDs. The 2D surface‐functionalized MHP renders significantly reduced trap density, environmental stability, and an ion‐migration‐immune surface in addition to a fast radiative recombination owing to its spatially and potentially confined charge carriers, simultaneously. As a result, heterophased MHP LEDs show substantial improvement in operational lifetime ( T 50 : >200 h) compared to conventional pure 3D or quasi‐2D counterparts ( T 50 : < 0.2 h) as well as electroluminescence efficiency (surface‐2D/bulk‐3D: ≈7.70 ph per el% and pure 3D: ≈0.46 ph per el%).