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Reduced Efficiency Roll‐Off and Improved Stability of Mixed 2D/3D Perovskite Light Emitting Diodes by Balancing Charge Injection
Author(s) -
Fakharuddin Azhar,
Qiu Weiming,
Croes Guillaume,
Devižis Andrius,
Gegevičius Rokas,
Vakhnin Alexander,
Rolin Cedric,
Genoe Jan,
Gehlhaar Robert,
Kadashchuk Andrey,
Gulbinas Vidmantas,
Heremans Paul
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201904101
Subject(s) - perovskite (structure) , materials science , quantum efficiency , optoelectronics , diode , light emitting diode , electron , exciton , layer (electronics) , nanotechnology , condensed matter physics , physics , chemistry , crystallography , quantum mechanics
Perovskite light emitting diodes (PeLEDs) have reached external quantum efficiencies (EQEs) over 21%. Their EQE, however, drops at increasing current densities ( J ) and their lifetime is still limited to just a few hours. The mechanisms leading to EQE roll‐off and device instability require thorough investigation. Here, improvement in EQE, EQE roll‐off, and lifetime of PeLEDs is demonstrated by tuning the balance of electron/hole transport into a mixed 2D/3D perovskite emissive layer. The mixed 2D/3D perovskite layer induces exciton confinement and beneficially influences the electron/hole distribution inside the perovskite layer. By tuning the electron injection to match the hole injection in such active layer, a nearly flat EQE for J = 0.1–200 mA cm −2 , a reduced EQE roll‐off until J = 250 mA cm −2 , and a half‐lifetime of ≈47 h at J = 10 mA cm −2 is reached. A model is also proposed to explain these improvements that account for the spatial electron/hole distributions.