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Elucidating and Mitigating Degradation Processes in Perovskite Light‐Emitting Diodes
Author(s) -
AndajiGarmaroudi Zahra,
AbdiJalebi Mojtaba,
Kosasih Felix U.,
Doherty Tiarnan,
Macpherson Stuart,
Bowman Alan R.,
Man Gabriel J.,
Cappel Ute B.,
Rensmo Håkan,
Ducati Caterina,
Friend Richard H.,
Stranks Samuel D.
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202002676
Subject(s) - passivation , materials science , halide , perovskite (structure) , degradation (telecommunications) , light emitting diode , optoelectronics , diode , quantum efficiency , chemical engineering , nanotechnology , inorganic chemistry , layer (electronics) , chemistry , computer science , telecommunications , engineering
Halide perovskites have attracted substantial interest for their potential as disruptive display and lighting technologies. However, perovskite light‐emitting diodes (PeLEDs) are still hindered by poor operational stability. A fundamental understanding of the degradation processes is lacking but will be key to mitigating these pathways. Here, a combination of in operando and ex situ measurements to monitor the performance degradation of (Cs 0.06 FA 0.79 MA 0.15 )Pb(I 0.85 Br 0.15 ) 3 PeLEDs over time is used. Through device, nanoscale cross‐sectional chemical mapping, and optical spectroscopy measurements, it is revealed that the degraded performance arises from an irreversible accumulation of bromide content at one interface, which leads to barriers to injection of charge carriers and thus increased nonradiative recombination. This ionic segregation is impeded by passivating the perovskite films with potassium halides, which immobilizes the excess halide species. The passivated PeLEDs show enhanced external quantum efficiency (EQE) from 0.5% to 4.5% and, importantly, show significantly enhanced stability, with minimal performance roll‐off even at high current densities (>200 mA cm −2 ). The decay half‐life for the devices under continuous operation at peak EQE increases from <1 to ≈15 h through passivation, and ≈200 h under pulsed operation. The results provide generalized insight into degradation pathways in PeLEDs and highlight routes to overcome these challenges.